Make Your Own Diagnostic Equipment (MYODE) (Includes circuit explanations, parts list and detailed explanation on how to build) By Mandy Concepcion
Make Your Own Diagnostic Equipment (MYODE) (Includes circuit explanations, parts list and detailed explanation on how to build) By Mandy Concepcion
Copyright © 2013 By Mandy Concepcion
This book is copyrighted under Federal Law to prevent the unauthorized use or copying of its contents. Under copyright law, no part of this work can be reproduced, copied or transmitted in any way or form without the written permission of its author, Mandy Concepcion. The information, schematics diagrams, documentation, and other material in this book are provided “as is”, without warranty of any kind. No warranty can be made to the testing procedures contained in this book for accuracy or completeness. In no event shall the publisher or author be liable for direct, indirect, incidental, or consequential damages in connection with, or arising out of the performance or other use of the information or materials contained in this book. The acceptance of this manual is conditional on the acceptance of this disclaimer.
About ASE Certification
We at Automotive Diagnostics and Publishing promote the ASE Certification program and encourage all beginning and advanced technicians alike to participate and get certified. We are not directly affiliated with ASE. ASE Automotive Technician Certifications are recognized throughout the United States by almost all county and state agencies as meeting the requirements to be considered an automotive technician. Many organizations and repair facilities nationwide have ASE Certification as mandatory for their technicians as part of their business model. It’s one thing to just show up for work; it is quite another to take control of your career, and get recognition for the knowledge and skills you’ve developed over the years. That’s what ASE certification is all about: helping you tell customers, employers, and other people about what you know. After all, being an automotive technician is not just turning wrenches. Your years of hard work show that you’ve gone the extra mile, and put in the time and effort to learn your trade. Your ASE certification patch is proof of it. Get certified now.” We are not directly affiliated with ASE. The Tech-2 is a registered trademark of Vetronix Corp. and GM The DRB III & Starscan are a registered trademark of DaimlerChrysler The NGS is a registered trademark of Ford Motor Co. Any other proprietary name used in this book was done purely for explanatory purposes.
Developed in the U.S.A.
Preface & Acknowledgements
This book, “Make Your Own Diagnostic Equipment” came about from the need of many readers and viewers to be able to make and maintain fairly simple diagnostic gadgets. It is meant to show and guide the professional technician and DIY mechanic on how to make these gadgets. In many cases, due to the nature of the equipment industry, it is very expensive or virtually impossible to get these tools. The reason being is that often times tool makers don’t see a profit in making these simple but effective gadgets. Most, if not all of these tools, are invaluable in diagnosing modern automotive systems. You can estimate that having one of these tools, at the right time when needed, will cut your diagnostic time by at least 50%. Of course, knowing how to use it is also important. However, by definition if you’ve already studied how the gadget works, how to build it an also ended up building it yourself, you’ve already passed the learning curve and chances are you’ll know how to use it. At the very least, reading this book will put you in a much better position to also asses diagnostic issues and on the use of other important tools of automotive diagnostics. It is our hope with this work to enlighten the professional and DIY mechanic on the use, construction and operation of modern automotive diagnostic gadgets. Use this information to the beast of your abilities and be on the diagnostic driver seat.
[email protected] (For further insight on the operation and testing of these components see our complimentary book & DVD-Videos to this series.)
Note Bout Building the Gadgets:
All parts are available at MOUSER.Com and DIGIKEY.com. Parts numbers have been given where applicable or are part and can be determined from the diagram. In some instances the part has been replaced by a newer version, use the compatible newer version instead. The rest of the parts are simple discrete components, such as resistors, diodes and capacitors. All values can be found at the schematic diagram for each gadget. In some cases you may have to slightly change and experiment with resistor and capacitor values, due to tolerance differences, your particular situation and use or for various other reasons impossible for us to predict. Building these gadgets can save you, the professional technician or DIY mechanic thousands of dollars. You’re also encouraged to visit our YouTube channel at “ADPTraining” and post comments and share views. We hope you get inspired and get to build some of these useful circuits. Thanks for reading and trying. Author, Mandy Concepcion… Automotive Diagnostics and Publishing
Make Your Own Diagnostic Equipment, Copyright 2013, All rights reserved.
Table of Contents
Automotive Low Pressure Transducer Building the Low Pressure Transducer Using the Low Pressure Transducer Polarity LED Test Light Using the Polarity LED Test Light Stress Loaded Test Light Using the Stress Loaded Test Light Building the Stress Loaded Test Light Fuel-Pump Relay & the Stress Loaded Test Light Dual Polarity & 5 Volt Reference Test Light Amplified Sensor Tester Injector & Coil Magnetic Detector Fuel Injector Pulser ECM-ECU Memory Saver Tool Loaded Injector Noid Light Using the Loaded Injector Noid Light 5 Volt Reference Simulator Parasitic Draw Amp Meter Using the Parasitic Draw Amp Meter Fuse Voltage Drop Short Identifier How to Use the Fuse Voltage Drop Short Identifier Ignition Primary DIS - COP Probe How to Use the Ignition Primary DIS Probe
Drive-By-Wire Motor Actuator Controller How to Use the Drive-By-Wire Actuator Controller Ignition Key Transponder Detector Using the Ignition Key Transponder Detector Magnetic Sensor Induction Simulator Using the Magnetic Sensor Induction Simulator O2 Sensor Simulator Using the O2 Sensor Simulator ABS Speed Sensor Simulator Using the ABS Speed Sensor Simulator ABS Speed Sensor Simulator, Bleeding the Brakes Optical CAM and CRANK Sensor Simulator Using the Optical CAM and CRANK Sensor Simulator OBD-2 Data Link Connector Breakout Box Using the OBD-2 DLC Breakout Box
Automotive Low Pressure Transducer
Pressure transducers are used in conjunction with a measuring device, such as a multimeter of oscilloscope to detect a changing pressure. Pressure transducers are very useful in detecting all kinds of auto repair issues, such as follows: When connected to the a fuel pressure regulator to detect minor fluctuations in the fuel pressure when injectors open and close, thereby, revealing a clogged injector. Used to detect exhaust gas flow output, revealing issues with the valve train. In case of a burnt valve, an exhaust pressure transducer will flag a busted valve if the signal is properly interpreted. There are dozens of cases when a pressure transducer is useful in auto repair and diagnostics. So here’s how to build your own pressure transducer. First, it’s worth saying that the hart of a pressure transducer is the piezo-electric device that does the actual measurement. If we were to build this tool from scratch, we would need a few auxiliary components to make the circuit work. Remember, this device is not ust a piezo electric gadget by itself. You need a way to process the signal worthy for an oscilloscope or graphing meter.
By far, the easiest and fastest way to make this device is to use an already made component. In our case, we’ve done our homework and researched various components. We’ll use a fuel tank pressure sensor for the hart of our pressure transducer, readily available at your local parts place or salvage yard. All modern cars use a fuel tanks pressure sensor. We made various transducers using Toyota and General Motors fuel tank pressure sensors and they all use 5 volts as a reference. Here in this circuit we can see that the pressure transducer is connected to two outside components, a 5 volt Zener diode and a resistor. The Zener and the resistor in series will give us the reference signal that the fuel tank pressure sensor needs to work. We will also use a 9 volt battery as our power source. It is possible to connect the 9 volt battery straight into the tank pressure sensor, but in our tests, we’ve seen issues with the readings at the higher end of the measuring scale.
This circuit says that current flows from ground, through the series Zener resistor pair and to 9 volt positive. The 5 volt reference is tapped right in the middle. We can then connect the tank pressure sensor reference voltage to this point between the Zener resistor series pair. And we can take our output signal right at the fuel tank pressure sensor output without any further processing. Remember that the tank pressure sensor is a high impedance device, fit for an oscilloscope, multi-meter of graphing meter.
Interpreting the output waveform is another matter, which takes some time to master and worthy of another video series. This circuit mean a saving of at least 100 dollars less, over whatever is in the market right now. With this parts list you can build your own pressure transducer and get reliable waveforms worthy of any modern laboratory. The parts list that follows is all you’ll need to build this device and get many years of service out of it.
Low Pressure Transducer Parts List:
(note: these are some possible fuel tankpressure sensors that can be used. There are hundreds that can be used. Almost any fuel tank pressure sensor can be used. Prices range for a new one $25 to $65 to a used one for $5). * 2005-12 GM original fuel tank pressure sensor 13502903 * 2007 Chevy Silverado 2500 - OEM Dealer part numbers: 16196060, 16238399, 8093776800, 8162384090, 09377680, 9377680, 8162383990, 8162117490, 8162572760, 12219388, 16217059, 16257276, STANDARD MOTOR PRODUCTS #: AS302 * 5.1 volt Zener diode - (Price $0.027 to $0.29) Part # (mouser 78-TZX5V1B, 78TZX5V1B-TAP, 771-NZX5V1B,133) (Digi-Key 1N5232BVSTR-ND, 1N5232BVSCTND) * Resistor - (Price $ ) (Part # Mouser 588-OD510JE, 588-OF510JE) * Black case - Small PVC pipe from hardware store. * Black vacuum hose from local auto-parts
Building the Low Pressure Transducer
You’ve previously seen how the low pressure transducer works. Now, we’ll show you how to build this gadget in the simplest way possible. As you can see, this tool requires only a few parts. The fuel tank pressure sensor, a resistor and Zener diode, a 9 volt battery and clip, and two alligator clips. The upper 50 Ohm resistor is a current limiter, and the 5 volts reference is taken at the junction point, between the resistor and diode. The two upward looking wire is the output to the voltmeter or scope, one at the ground, the other at the fuel tank pressure sensor signal terminal. The other two terminals at the sensor, are the 5 volts reference and the sensor ground. In this build animation, we’ve also used two alligator clips, used for connecting to the vehicle battery. This is not necessary, but we just give you the option of either the 9 volt battery or vehicle power. The Zener diode and resistor combo will always regulate the voltage to 5 volts, which is what the sensor needs. This entire circuit can be folded, and then encased in a PVC or plastic enclosure for protection. It is also possible to use epoxy resin to encase the whole circuit and protect it from moisture. Finally, you can see the pressure or vacuum port at the end, which is where a hose is connected to sample the pressure. This gadget, if encased in epoxy will render many, many years of service.
Using the Low Pressure Transducer
There are many instances where the low pressure transducer is quite useful. The basic use of the low pressure transducer is to detect small variations or vibrations that may lead to the interpretation of a faulty component. The word interpretation is the key here. Following we’ll show you how to interpret the this components waveform in various scenarios. First scenario. How to detect a clogged fuel injector.
Connecting the pressure transducer to the fuel pressure regulator will make it act as if it were a microphone connected to the fuel rail. If dealing with a returnless fuel system, then you can also connect a normal diaphragm fuel pressure regulator to the fuel rail, then connect your self built low pressure transducer to it. The idea is to detect small variations in the fuel pressure regulator diaphragm. Every time an injector open, the diaphragm vibrates in a specific way detected by the transducer, which in turns is connected to the oscilloscope.
In this snap-shot we can see how the injector humps look on a good engine. The injector pressure differential humps look fairly even, testifying to the fact that all injectors are flowing the same amount of fuel whenever it is open. Then, we see a different waveform showing a clogged injector. Here we can see the absence of a hump, pointing to a clogged injector, an electrically open injector or a general low fuel flow condition. This technique will not eliminate the final test we may want to do, once the injector has been removed. But at least this technique serves as a huge guide in condemning a clogged injector.
Second scenario. Detecting possible burnt valves by analyzing the exhaust flow. Whenever a cylinder with faulty valves goes on combustion it leaves a specific trace at the intake manifold and exhaust gas flow. This is a typical good trace for the exhaust backflow. In here, there are no faulty issues with the valve train. Now we can see a different waveform showing the down sloping humps typical of a burnt valves. Keep in mind that sometimes semi burnt valves will keep the cylinder firing or combusting, albeit, with degraded performance, but the tell tail signs are left on the waveform. Identifying this issue is a must when using the low pressure transducer.
Third scenario. Detecting valve timing or issues with the transducer connected to engine vacuum. We say again that in all these scenarios, the more cylinder symmetrical the waveform is the better. Disparity between cylinders is an indicator of an issue. So, even if you don’t know how to read these low pressure transducer waveforms that much, think of the word symmetrical, and use it as a guide.
Valve issues can also be traced with the low pressure transducer, whether timing or burnt valves. Timing issues are not that relevant anymore due to electronic control. But, there are instances when the ECM skews timing due, to say a faulty knock sensor. Let’s see how this works. Engine valve issues will always cause a fluctuation in the waveform that goes above or below the average of the other cylinders. This is where comparative wave analysis between cylinders becomes important. In general the more symmetrical the waveform and distribution above and below the median point reference line, the better the condition of the engine. Most fuel tank pressure sensors, which is the basis of our self made transducer, have a 2.5 volt median point. You can look at 2.5 volts as the zero line. The low pressure transducer can be used in a thousand and one different ways. Almost any engine scenario, lean and rich condition, ignition waveform analysis without dismantling anything, valve issues, clogged converter and much more can be determined using this device. We’ve shown you how to make this gadget in our other article. It is now up to you to learn how to use it and get many years worth of results out of it.
Polarity LED Test Light
There are many instances where you’ll need a way to determine the polarity of a circuit or whether it was connected properly. Many times the need for this type of work comes from obsolete adaptations done to the car, such as installing a new cooling fan motor or power door locks.
With a few inexpensive parts, you can build your own LED bi color test light that determines polarity on a circuit. Some of these LED test lights can go for over 100 dollars. With a mere 5 dollars or less you can build this test light with readily available parts. We’ll use the following components: An LED from Radio Shack part number 276/012 at about a dollar 49. You can also get it from Mouser and Digi Key. We’ll use a couple of pre-made jumper wires with alligator clips, and just cut the wire at the mid point. You could use your own leads and buy the clips separately at Mouser or Digi Key too. The resistor is a 330 Ohm or orange orange brown and is a one eighth Watt. You could use a quarter Watt if that’s all you can get. We also use the casing of an cheap dollar fifty test light available from any auto parts store or hardware.
Using Ohms law of E = I divided by R, we arrive at the 330 Ohm resistor, which serves as a current limiting component that protects the LED.
In this circuit current flows from ground, through the LED and 330 Ohm resistor. The LED will glow green, indicating correct polarity. If the test light is connected in reverse, then the LED will glow red. Since this circuit is polarity sensitive, when you’re building or soldering the test light, the flat part of the LED casing is the negative side. It also doesn’t matter to which side you connect the resistor to. All in all, this is a very simple and useful circuit to build. The uses of this circuit are infinite. For example, you can use this test light when trying to identify the heater wires on an Oxygen sensor. Often, a universal O2 sensor is used, which has no connector to it and it gets tough to identify the heater wires. With this gadget you don’t even need to refer to the wiring diagram. Just raise the car, key-on-engine-off and probe. And, since this circuit only draws a mere 30 milli Amps, it is safe to use on low voltage circuits as well. So, it is fine to use it on Hall Effect crank and cam sensors, or any other ECM circuit to identify the power feed wire for these components. However, it is not ok to use this circuit on high current circuits to determine proper current supply, current supply being the key point here. This is a very common mistake when these types of test lights are used, such as the famous probe or any other. The issue is that this test light will light up with very little current. If you’re trying to determine say a 10 Amp circuit that feeds a fan motor, use another equipment, called the loaded test light, seen elsewhere in here. Remember, this light emitting diode or LED test light will only show correct polarity, good for all circuits, including low power ones like crank and cam sensor, but not good to read high loads or high current specifications. These sturdy test lights are short circuit protected due to the resistor and bi polar nature of the LED. With little care it’ll last you for many years to come. Building the Polarity LED Test Light
The Polarity LED Test Light is used, if you need a way to determine the polarity of a circuit, or whether it was connected properly, and in issues such as installing a new cooling fan motor or power door locks. With a few inexpensive parts, you can build your own LED bi color test light that determines polarity on a circuit. Some of these LED test lights can go for over 100 dollars. With a mere 5 dollars or less you can build this test light with readily available parts. It is also worth noting that this gadget can also be enclosed in an epoxy resin enclosure, keeping it from humidity and moisture.
Seen here, only a few parts are needed to build the Polarity LED Test Light, a 330 Ohm resistor, a dual color LED, and two alligator clips. The enclosure can be either epoxy, plastic or a PCV pipe. Here, we can see that the 330 Ohm resistor is connected to the positive side of the circuit. An important fact to notice here, is how we connect the LED light. All LED lights have a longer leg. This is always the positive side of the circuit. So, in this case, we connect the longer positive LED leg to the resistor, which provides the positive side of the circuit. The other side of the LED, is connected to the negative alligator clip. This completes the entire circuit. The 330 Ohm resistor is used for current limiting, to protect the LED from excess current. This LED, by definition is a dual color. So, if you try to connect the Polarity LED Test Light backwards and if the circuit polarity is wrong, the LED will change color to red. It’ll be green if polarity is correct, and red if it’s inverse polarity. Once encased in it’s enclosure, especially if it’s an epoxy protection, the Polarity LED Test Light will render itself useful for years to come.
Using the Polarity LED Test Light
The polarity LED test light is a wonderful and safe tool to use on ECM circuits. It has the same construction as a logic analyzer used on chip sets throughout the electronics industry. The reason why the LED test light is safe, is that it only draws between 20 to 30 milli Amps of current, making it safe for CAM and crank sensors, reference voltages and solenoid circuits.
A word of caution, the LED test light can not be used to test higher current devices. Not because there’s any danger in doing so, but because the results are useless. If for example, when using the LED test light to test an ignition coils or injector ground, it will check out fine and yet the circuit could still have a poor ground. And that’s because the LED will illuminate with only 20 milli Amps. This is a common mistake done in the field, using an LED test light to test high current components. There are few scenarios worthy of the LED test light. First scenario, testing a solenoid power and ground. Since this test light has only two terminals, it is necessary to constantly change the polarity of the test light. So, connect the positive test light leed to 12 volt power, and then probe at the solenoid ground side. You should see a green or yellow light, depending on the LED used. Then change the leeds of the test light to chassis ground and the solenoid pulsed terminal. You should see a blinking red and green light, at about 400 Hertz. This is the typical duty cycle frequency of a solenoid.
Scenario two, testing a hall effect CAM or crank sensor. These sensors tend to draw at least 40 or 50 milli Amps, enough for the LED test light. Place the negative test light leed at ground, then use the positive side to probe at the signal wire. When cranking, you should see a blinking red and green light. Don’t use it on a running engine, as the frequency is too high for meaningful results. The same can be done to test the CAM and crank sensor power and reference voltage. Most Hall-Effect reference voltages are in the 6 to 8 volt range, so the LED test light is a good testing tool. Another word of warning here is that the LED test light may not be practical to test magnetic CAM and crank sensors. These sensors produce very little current, not enough to power the 20 milli Amp LED test light. To test magnetic sensors we’ll need an amplified LED test light, which has an internal circuit that takes the magnetic signal, amplifies it a bit and drives the small LED. This is an even more specialized tool, and will be covered later on.
Stress Loaded Test Light
A very big misconception in the field is that of the meaning of a load. A load is not a voltage or current. A load is not applying voltage or current to a circuit to see what it does. A load applied to a circuit will not destroy the circuit, it will simply blow it’s respective fuse if too high. A load can only mean one thing, a load is a resistance. The amount of Ohms or resistance value will determine how big the load is.
For example, a low ohm resistor, say 5 to 10 Ohm is a very large load. On the other hand, a 100 to 1000 Ohm resistor is a very small load. So, the relationship of load to Ohm value is inversely proportional. The reason why a small Ohm, or small resistive value is a large load, is because the smaller the Ohm value, the higher the current flow of electrons. Remember this, high current equals heat and therefore stress to the circuit. All circuits are protected by a fuse, so, when using the stress loaded test light, do not remove the fuse that feeds the circuit you are testing. Also, the stress leaded test light is protected by a second fuse. In our stress loaded test light, we’ll be using what’s considered a general load or resistance value of 5 Ohms.
In the past, automotive technicians have used a head light to do a loaded circuit test, which also has a nominal 5 to 10 Ohms resistance. The issue with a headlight is that as the filament heats up, the resistance changes or tends to drop and, the worse part is that if it falls it breaks into pieces. With the stress leaded test light all these issues are resolved. The only other piece of equipment that even compares is the loaded battery alternator tester. These come either with a load knob, which increases the load as you turn, or an electronic unit that creates a low resistance value. It is amazing that no other equipment manufacturer has put out a device to stress load the circuit as you’re testing it. Loading a circuit during testing is done so that it’s faulty issues reveal themselves. This can be applied especially to ground and power feed tests, and to higher current components, such as cooling fan motors, lighting circuits, compressor clutches and even injectors. This is how the stress loaded test light works. We’ll start by using two large ceramic resistors, connected in parallel as our load. These resistors are inexpensive, and take up a lot of heat. Remember, a high load means a small Ohm value, and therefore, some heat. It is also a good idea to either use a heat sink on the resistors, or a metal case or pipe for the test light itself. The idea here is to use inexpensive components, lowering the cost to make this super useful gadget.
In this circuit we can see that current flows from ground, through the parallel resistor pack, through the 5 Amp fuse and to 12 volt power. Also, parallel to the dual resistor load is a series single color LED and a 630 Ohm resistor. Here’s how these two guys work. Whenever the circuit that we’re testing, whether ground or power, can provide enough current, about 2.5 Amps will flow through the load resistors. Then, at the same time about 20 milli Amps also flow through the LED, lighting it up. On the other hand, if the circuit can not provide enough power, or at least 2.5 Amps, the load resistors will suck up all the current and the LED will never see enough current for it to light up. We’ve also added an extra screw-on light bulb, to be able to detect current intensity, since LED are great for on and off situations, but are not good at providing levels of intensity.
The end result is a complete circuit loading solution that’ll give you years of operation. Next, we’ll see how to use this tool in the real world.
Using the Stress Loaded Test Light
The stress loaded test light can be used to find almost any issue related to automotive electrical work. These are some scenarios where it can be used to find the following. Short circuits Open Circuits To see there’s proper ground Alternator charge wire To test the power feed capabilities of components, such as cooling fan motors, solenoids, injectors, lock actuators and any other component that draws high current. This gadget can be used as a substitution box in place of the fuse, or a the final load in a circuit, but removing the actual component and see if the circuit still performs. Here are two scenarios that we’ll analyze to see how all this works. Scenario one. Using the stress loaded test light to find an issue with the ground. Remember, ground doesn’t mean that it is electrically inert. It means that it is the common side of the circuit and the supplier of electrons. So, the ground side has to be as good as the power, or voltage side of the circuit. Here, we can see how for example, the ground strap between the battery, chassis and engine block is held only by a few strand of wire. You can also see this as a high resistance point, and, as explained before, a high resistance point is a small load. In this case it is also a bottleneck, preventing current flow.
The issue here is that a volt meter alone can not detect this issue. If you measure with the volt meter at each side of the resistance point, signified here by a few strands of wire, the volt meter will read exactly the same, 12.6 volts or battery voltage, when measuring across the positive of the battery. In this case, disregard the polarity of the volt meter. The problem in all these cases is that the trouble spot in the circuit can provide enough
power to drive the volt meter, since it doesn’t take much, only in the micro Amp range. By connecting the stress loaded test light after the trouble spot, you’ll load the circuit and force it to flow electrons or current through it. In this case, once the gadget is connected after the trouble spot you will see no voltage with a volt meter, and the test light LED and bulb will not be lit. This is a dead giveaway that there’s an issue at hand. The repair in this case is to keep wiggling and searching until the trouble spot is found.
Scenario two. Finding a short circuit. In this case we’ll use the stress loaded test light in the familiar substitution method. This is the same as using the old head light, but now you don’t have to worry about breaking the headlight.
Remove and place the gadget as a substitute for the fuse. Since our stress loaded test light is a 5 Ohm resistance, it acts as a straight through wire, feeding the respective circuit. In this case, by substituting the fuse, the gadget will light up as long as the short circuit exists. It is only a process of systematically disconnecting the different components one by one. As soon as the shorted component is disconnected, the LED and light bulb will go off, since there would be no more current flow. This is a very easy and simple way to use our gadget. Remember, the uses for the stress loaded test light are almost infinite, when it comes to automotive electrical work. With enough time and experience, this unit will provide you with years of service.
Building the Stress Loaded Test Light
A very big misconception in the field is that of the meaning of a load. A load is not a voltage or current. A load is not applying voltage or current to a circuit to see what it does. A load applied to a circuit will not destroy the circuit, it will simply blow it’s respective fuse if too high. A load can only mean one thing, a load is a resistance. The amount of Ohms or resistance value will determine how big the load is. For example, a low ohm resistor, say 5 to 10 Ohm is a very large load. On the other hand, a 100 to 1000 Ohm resistor is a very small load. So, the relationship of load to Ohm value is inversely proportional. The reason why a small Ohm, or small resistive value is a large load, is because the smaller the Ohm value, the higher the current flow of electrons. Remember this, high current equals heat and therefore stress to the circuit. All circuits are protected by a fuse, so, when using the stress loaded test light, do not remove the fuse that feeds the circuit you are testing. Also, the stress leaded test light is protected by a second fuse. In our stress loaded test light, we’ll be using what’s considered a general load or resistance value of 5 Ohms. In the past, automotive technicians have used a head light to do a loaded circuit test, which also has a nominal 5 to 10 Ohms resistance. The issue with a headlight is that as the filament heats up, the resistance changes or tends to drop and, the worse part is that if it falls it breaks into pieces. With the stress leaded test light all these issues are resolved. The only other piece of equipment that even compares is the loaded battery alternator tester. These come either with a load knob, which increases the load as you turn, or an electronic unit that creates a low resistance value. It is amazing that no other equipment manufacturer has put out a device to stress load the circuit as you’re testing it. Loading a circuit during testing is done so that it’s faulty issues reveal themselves.
This can be applied especially to ground and power feed tests, and to higher current components, such as cooling fan motors, lighting circuits, compressor clutches and even injectors. This is how the stress loaded test light works. We’ll start by using two large ceramic resistors, connected in parallel as our load. These resistors are inexpensive, and take up a lot of heat. Remember, a high load means a small Ohm value, and therefore, some heat. It is also a good idea to either use a heat sink on the resistors, or a metal case or pipe for the test light itself. The idea here is to use inexpensive components, lowering the cost to make this super useful gadget. In this circuit we can see that current flows from ground, through the parallel resistor pack, through the 5 Amp fuse and to 12 volt power. Also, parallel to the dual resistor load is a series single color LED and a 630 Ohm resistor. Here’s how these two guys work. Whenever the circuit that we’re testing, whether ground or power, can provide enough current, about 2.5 Amps will flow through the load resistors. Then, at the same time about 20 milli Amps also flow through the LED, lighting it up. On the other hand, if the circuit can not provide enough power, or at least 2.5 Amps, the load resistors will suck up all the current and the LED will never see enough current for it to light up. We’ve also added an extra screw-on light bulb, to be able to detect current intensity, since LED are great for on and off situations, but are not good at providing levels of intensity. The end result is a complete circuit loading solution that’ll give you years of operation. Next, we’ll see how to use this tool in the real world.
Fuel-Pump Relay & the Stress Loaded Test Light
Due to the importance of using the stress loaded test light or any form of loading the circuit to stress the faulty issue, we’ve created the following explanation on the subject. In this example, we’ve taken a faulty fuel pump relay, and stress the circuit to see how this affects it. We’ll start by saying that this is a simple fuel pump relay actuated by the ECM, much like any other similar unit. In our case, the relay contacts have become pitted over time and have developed severe carbonization and therefore, resistance. As in many a similar cases, the excess resistance makes the fuel pump run slower, due to lack of needed electrical current. The end result is engine performance problems and lack of power. Before exposing the procedure we have to know a few caveats. One, at this time, the diagnostic technician has no idea where the faulty issue is at. In other words, he doesn’t know that the pump relay contacts are pitted, carbonized and resistive. Two, since he doesn’t know where the issue is, the use of a voltmeter is irrelevant. All the technician can do with a voltmeter is probe between battery positive and the fuel pump, and just know there’s a voltage drop somewhere, if at all detectable. And three, this issue is not a dead open circuit. It is a semi open or high resistance issue, but, not high enough to cause a severe voltage drop anywhere, especially at the current rating that this fuel pump operates. Most newer fuel pumps operate at about 1.4 Amps. In this case the current draw was even less, due to the high resistance pitted relay contacts. Ladies and gentlemen, this situation is exactly what you would find in 99% of real world cases. Not quite a cut and dry situation, whereby is not a dead open or shorted circuit. And, where you have no idea where to start the diagnostic. Here’s how the stress loaded test light can help.
First, we disconnect the fuel pump connector and substitute it with the gadget. All we
want to do now is find out where in the circuit the issue is at. So, the only way to do this is by stressing the circuit. By putting a big load on the circuit, we are now flowing a higher current value. You won’t see 2.5 Amps at this time, due to the pitted relay contact. But, the circuit will be stressed at it’s maximum, according to whatever the resistance is at the relay contact. At this time, two things will happen. One, the LED and light bulb at the gadget won’t light up or if so, very dimly. It is now up to the technician to start tracing down and hunting the resistance spot. But, at this time we do know for sure, due to the LED and bulb state of illumination, that the circuit does have a high resistance spot. So, there’s no need to replace the fuel pump. Lots of fuel pumps get replaced unnecessarily. The first benefit of this gadget has been realized. We now can continue on to the next phase of the diagnostic, tracing and hunting.
At this time, the resistance spot is now more visible through the use of a voltmeter. Remember, we still don’t know where the issue is. So, using a wiring diagram, we start probing, or voltage dropping at different sections of the circuit. The issue could be anywhere, so it’s only a matter of tracing. We trace sources of resistance like connectors, wires exposed to the elements under the car, or under the carpet where the driver may have spill some water, and at the relay. As soon as we probe the relay, bingo, we see it. We would have never seen this issue without the help of the stress loaded test light, since the old fuel pump wasn’t drawing that much current to begin with. So, the issue was never that apparent. The higher current through the gadget, stressed the circuit and made the issue traceable with the voltmeter, graphing meter or any other piece of equipment fit for the task. One final word, it is also possible to use the stress loaded test light LED and bulb alone to trace the issue. The process is that of wiggle and shaking. As soon as the resistive spot is found, most of the time you’ll see it at the LED and light bulbs. The LED will detect it first. If the LED is lit, but not the gadget’s light bulb, then keep tracing with the bulb alone. Once the spot is repaired, then both LED and bulb will light up brightly. Giving the final benefit of proving that your diagnostic and repair were performed properly. Like any piece of equipment, it takes some practice and experience to become proficient at using, the stress loaded test light. Happy hunting’s.
Dual Polarity & 5 Volt Reference Test Light
The Dual Polarity & 5 Volt Reference Test Light is a very useful and easy to build gadget. It’s made to be able to quickly detect a circuit or component polarity, or which is positive or negative. It’s easy to test the polarity of a circuit, whether it is positive or negative by using the circuit featured here. This test light also test for proper 5 volt reference coming out of the ECM. The circuit has a high input impedance to avoid loading the circuit being tested. Remember, any time you test a circuit, you need to take into account the input impedance of the test equipment. This is not an issue on high current devices, but it is a problem on low power sensors and ECM input circuits.
Basically, the input impedance is when you short the actual signal, because your measuring or diagnostic equipment has a very low resistive or Ohm value. In out case here, this test light has 1 mega, or one million Ohms of input resistance, meaning it won’t short the low power signal produced by a sensor or ECM circuit. The Dual Polarity & 5 Volt Reference Test Light circuit is a very simple one. It employs two basic circuits within the test light, which you can then encase in a regular clear inexpensive test light body that you can purchase at the local parts place.
Here’s how the Dual Polarity & 5 Volt Reference Test Light works. The circuit is composed of two independently operating circuits. One tests the 5 volt reference, and the other tests the polarity of the circuit. If the gadget’s red LED lights up, then you know that either the polarity is wrong, or the test light has been wrongly connected. If you check for connection and shows a properly connected gadget, still with the red LED On, then polarity is faulty. Someone has crossed a wire somewhere, or, as it normally happens, there’s a shorted ground wire touching somewhere. In the diagram, we see at the 5 volt reference side of the circuit, that current flows from the black alligator terminal, through the yellow 5 volt LED, through the 1.5 Zener Diode, the 50 Ohm resistor, and finally to the tip of the probe, which could be the ECM provided 5 volt reference. The 5 volt reference LED circuit is calibrated for 5 volts. The Zener diode is a 1.5 volt unit, the yellow LED drops the typical 2.5 volts, and the rest of the voltage is dropped by the current limiting 50 Ohm resistor. This circuit side is very sensitive, and it will also light up above 5 volts, or together with the green LED. The nice thing about this circuit, is that if you probe and only the yellow LED lights up, it is an ECM provided 5 volt reference.
In the second part of the circuit, we see current flows through either one of the LED diodes. If the polarity of the component or circuit is correct, then the green LED will light up, otherwise current will flow at the red LED, indicating a wrong polarity issue, as in a crossed or shorted ground wire. Either of these two LED is also protected by the 330 Ohm resistor, as a current limiter, thereby preventing over current and damage to the LED. Finally, we should also draw attention to the regular diode found at the positive terminal, right after the alligator clip. This is a polarizing diode and basically directs the flow of electrons. It is the one which controls how the dual green and red LED lights react to circuit polarity. The Dual Polarity & 5 Volt Reference Test Light seen here is an evolution in the right direction from other LED test lights, since it can also detect 5 volt reference ECM circuits. Other LED test lights can also detect 5 volt reference, but they’re not calibrated for it. This gadget is calibrated for 5 volts at the yellow LED. Used properly, it can provide you with years of service.
Amplified Sensor Tester
How many times have you felt the need for a simple gadget that lets you easily test crank and CAM sensors, wheel speed sensors, and even Oxygen sensors. Well, this is it. This one does take a bit of work to assemble, but by far it is considered an easy project.
The way the Amplified Sensor Tester works is by amplifying the input signal, to be able to drive the LED indicators. Most sensors, even if they produce a high enough voltage, do not carry much current to drive the LED. This can be said of magnetic crank and wheel speed sensors, O2 sensors and various others. A voltmeter can be used to see voltage, but the human brain wasn’t meant to process fast moving digital numbers. In case of our gadget, the LED will quickly identify the incoming signal. At the same time, the variable resistor or potentiometer can be used to control the gain, or amplification factor of the unit. The 25 cents, 741 op amp, is the core of the amplified sensor tester. Its non-inverting input is used to test the signal for polarity. It has a gain of around 150, which enables it to test very low voltage levels, as in a magnetic crank sensor, or an O2 sensor. The test result is displayed through the two LED’s one and two. LED one, lights up by positive polarity, and LED 2, lights up by negative polarity. If testing a wheel speed sensor for example, you would see a blinking green and red LED, depending on the rotational speed of the wheel.
With a simple universal PC board, you’ll be able to build and solder the entire circuit, and get many years of service out of this amplified sensor tester.
Injector & Coil Magnetic Detector
How many times have you encountered a vehicle, with a coil on plug misfiring engine, which is so tight, that you would need at least half an hour to dismantle the surrounding plastic parts, just to get access to the injector or ignition coil.
Well, we now present you here with a very simple gadget that definitely works. This is an Injector & Coil Magnetic Detector, with the ability to detect high current devices, but more aptly made for ignition coils and injectors. The gadget circuit is very simple. It uses an inexpensive component called, a reed switch. This is nothing more than a simple contact, On and Off clear glass device that’s activated by magnetic fields. It is sensitive enough to detect ignition and injector coils. This gadget however, is not meant to be used with an oscilloscope to be able to read coil and injector waveforms, picked up from the air. For that you’ll need an Amplified Injector & Coil Magnetic Detector, which we’ll cover later on. This simple gadget will tell you right away whether a coil or injector is operational, is being triggered by the ECM, or that it’s building up a good magnetic field around it. It won’t tell you if the injector is clogged, or if the plugs are fowled up, but it’s a tremendous starting point for your diagnostics. The circuit is a simple series type, which includes a 9 volt battery, a one K resistor as a current limiter, an LED to signal the presence of a coil or injector actuation, and the actual reed switch. It is important to keep the reed away from the circuit, and encase it in some form of probe, as shown here. We’ve used a simple clear body of a pen, and a small enclosure of either plastic or P C V tubing to protect the gadget. The cost of the Injector & Coil Magnetic Detector is less than 3 dollars, can detect a working cylinder by just probing from as far as 7 inches, and with some practice and a small metal shield can be made to pinpoint higher current electrical shorts, by tracing the wire through the harness. In the past, some techs have used a compass to do similar tasks, but the Injector & Coil
Magnetic Detector is more exact and professional, providing you with years of excellent service.
Amplified Injector & Coil Magnetic Detector
The Amplified Injector Coil Magnetic Detector is a unique gadget. It is capable of detecting the magnetic signature of ignition coils, injectors, as well as many other types of devices that draw current. It can even detect the magnetic field from a magnetic crank or CAM sensor, without any physical connection to it.
How is this possible? Well, simply put, all electrical devices do put out a magnetic signature or field, which is detected by the Amplified Injector Coil Magnetic Detector probe, actually a simple inductor coil, and amplified by the circuit. The Amplified Injector Coil Magnetic Detector is meant to be used with an oscilloscope or graphing multi meter, where it is then plotted into a waveform for measurements. As with our other gadget of the same nature, the Injector Coil Magnetic Detector, you can also encase the Amplified Injector Coil Magnetic Detector in a P C V enclosure and a clear body of a pen for the probe. This simple gadget is built into a universal printed circuit board found at any electronics parts place for a few cents.
Here’s how the circuit operates. The probe tip is composed of an inductor or coil of 1 milli Henrys, encased into the clear body of a pen. The output of the inductor probe tip is fed into the 741 Op Amp, which then acts as a waveform amplifier with about a gain of 20. The 741 Op Amp is an inexpensive chip, that’s mounted on the universal PC board, combined costing less than a dollar. The other resistors and capacitors are standard supporting components for the 741. A 2.2 mega Ohm potentiometer is then used as a gain control to adjust the output taken after the 220 micro Farads and 10 Ohm resistor. A switch is also used to turn the Op Amp on and off, and the entire Amplified Injector Coil Magnetic Detector runs on a 9 volt battery, readily available anywhere. Finally, remember that the output of the Amplified Injector Coil Magnetic Detector is fed into an oscilloscope or graphing meter. There is no other way to detect ignition issues on a faulty injectors or ignition coil faster than with a scope. The use of the Amplified Injector Coil Magnetic Detector and a oscilloscope will allow you, by remote control, to detect if the issue is a bad spark plug, injector driver, clogged injector, faulty coil, ignition wires or any other issue impossible to prove without a scope. The usefulness of this device is that the actual waveform can be captured without making a physical contact with the wires. Companies like Snap-On and Sun have carried devices such as this one in the past, but are nowhere else to be found today. The Amplified Injector Coil Magnetic Detector is easy to make, and with experience can be utilized in ways that’ll satisfy you, and provide years of service.
Fuel Injector Pulser
Injector pulsers are a main staple component in the arsenal of a modern automotive technician, D I Y aficionado or enthusiasts, who needs to perform diagnostics on fuel injectors. The uses for a fuel injector pulses are varied. It is used to pulse and measure the electrical characteristics and general health of an injector, to determine if the injector is clogged, by doing a fuel flow test, and for to fast pulse and clean the injector using special solvents. In essence, this device is what you’ll find inside the ECM, with the exception that the LM 555 timer chip is substituted by the ECM processor.
As with many of our other gadgets, this circuit can be built into an inexpensive universal PC board. The 555 timer is a popular oscillator chip that creates the pulse signal. It is a 25 cent component. This entire circuit can be built for less than 4 dollars. An LM 393, or Dual Differential Comparator chip is also used to create the duty cycle part of the signal. The other components are off the shelf resistors, potentiometers and small capacitors readily available anywhere. This circuit works as follows. This device uses a built in pulse width modulated signal generator circuit for triggering a power MOSFET, which is a high current transistor. This particular transistor, the IRF740 is rated up to 400V and can switch around 10 Amps which makes it quite useful for power switching in inductive loads. The Fuel Injector Pulser circuit will run on a 12V DC supply.
The circuit is great for controlling the power delivered to an injector, and by adjusting the pulse width, you can easily control the fuel flow, flow, which is useful for doing a fuel flow test, where the injector pulse specifications is very important. When doing a fuel flow test, the frequency and duty-cycle of the pulse has to be exact, but more on this later. The 555 timer chip develops the pulse wave needed, but with no power to it. It is then fed into the LM393 for processing. The two potentiometers control the frequency and the duty cycle of the pulse, but also at very little power levels. This is called the pre amp part of the circuit. Finally, the MOSFET, or field effect transistor acts as a current amplifier, and is able to drive the coil of the injector. This is the power stage of the circuit, and it is also protected by a fly-back diode, and 1 micro Farad capacitor, to protect against the collapsing magnetic field high voltage at the injector coil.
The Fuel Injector Pulser is meant to also be used by pulsing the injector for a specific amount of time, collecting the fuel or cleaning fluid, and measuring against a graduated beaker. This is the definitive way to know for sure if the fuel injector is not clogged. The unit can also be encased in a plastic enclosure, fitted with a long lead cable for testing injectors. This is a rugged injector pulser, and with proper care should serve you for many years to come.
ECM-ECU Memory Saver Tool
How many times have you disconnected the battery, and found out that the radio station memory settings are wiped clean, as well as the engine performance is lacking. Well, it all has to do with the KAM memory. KAM stands for Keep Alive Memory and it’s a form of adaptive memory. KAM memory works as follows, whenever you drive your vehicle, the car’s ECM or engine control module learns each sensor imperfection, and records it on a special memory.
This memory has to be connected to power at all times, hence the name, keep alive memory. memory. Anytime the battery is i s disconnected, the KAM memory goes out. In other words, it gets erased. It could take up to a few weeks for the old parameters and imperfections to get recorded again. In the meantime, your vehicle will suffer from drivability issues. It simply won’t work the same until the KAM is recorded again. Other issues with disconnecting the vehicle’s vehicle’s battery is loss of radio, climate control, GPS and other telematics in the car. car.
In order to do away with all these issues you need a memory saver tool. This tool is connected to the vehicles cigarette lighter or OBD 2 connector to keep the memory going after the battery has been disconnected. In other words, the 9 volts put out by the memory saver tool is enough to maintain the memory chips inside the vehicles different computers. We have compiled and made available three separate memory saver tools. They’re basically the same, but use a different battery or connection arrangement. The first tool uses a simple 9 volt battery and is connected to the lighter plug. Connect the center electrode of the lighter plug to the 9 volt positive terminal. The 9 volt negative terminal goes on the outside electrode of the plug. So, all these plugs are tip positive, as it is called in electrical jargon.
The second tool uses more or less the same arrangement, but uses six double A batteries instead. Each double A battery is about 1.5 volts, times six of them makes it 9 volts. Although the vehicle is a 12 volt system, 9 volt is enough to keep the memory going. Finally, we show you the more advanced of the three memory saver tools, the OBD 2 connector based tool. The problem with the cigarette lighter tool is that often times, the respective fuse is blown. If this is the case, connecting the tool will serve no purpose. The
9 volts simply won’t reach the circuit, and you probably won’t know it. The end result is loss of KAM memory. So, the OBD 2 tool was created to apply power to pin number 16 of the connector, which is supposed to be constant power. Then pins number 4 and 5 are connected to the 9 volt battery ground. With the OBD 2 connector memory saver tool, there’s no way the tool won’t be able to do it’s job. It will always be connected, and the KAM memory will never loose it’s touch. This very simple tool is largely overlooked at many repair shops. If you ever go for a battery replacement, ask to use this tool. Even if your battery is discharged, the leftover charge is enough for the KAM memory. The moment your battery is disconnected, that’s when you loose it all. Not a good thing, and with proper care, the memory saver tool will give you the desired results for many years to come.
Loaded Injector Noid Light
NOID lights are a main stay in automotive diagnostics, and injector repair. A Noid light is connected across the injector circuit, by disconnecting the injector circuit, and connecting it in place of the injector. The issue with a noid light is that it barely loads the circuit. In other words, a noid light is a regular filament light, which draws very little current, and not stressing the circuit. In other words, you could still have a faulty injector driver transistor and the noid light would blink like nothing was wrong. This is the danger of being misled by the noid light.
The Loaded Injector Noid Light is the next step in evolution for a noid light. It is a simple gadget. It also proves how little attention is paid by equipment makers to what’s really needed out in the field. The Loaded Injector Noid Light is a simple filament bulb, which is needed for injector testing, and a 20 Ohm resistor in parallel with it. An LED is not a good option to test injectors. It simply draws too little current for the measurement to be definitive. The Loaded Injector Noid Light will pinpoint issues with the injector driver transistor, the 12 volt power feed to the injector, the ground at the ECM or the injector itself. Here’s how this simple, but updated gadget works. Current flows from the ECM ground, through it’s driver transistor, and through the injector coil to 12 volt power.
Remember, at idle is not 12.6 volts anymore, and more like 14.7 volts. At that voltage level, any injector will draw a nominal 950 milli Amps. With the injector disconnected, the 20 Ohm resistor across the noid light and the filament light bulb draw about 1.1 Amps or so. This is within the range of current for an injector driver, and it’s sure to stress the circuit to its maximum. For the most part, injector drivers can handle a lot more than 2 or 3 Amps, so the Loaded Injector Noid Light is not that stressful to the circuit, but does the ob nicely. When using the light, there are various techniques you can do to identify which part of the system is causing problems, such as injector driver transistor, voltage power feed to the injector, power relay, the ground at the ECM, ground wire or the injector itself. We’ll discuss these techniques later. With proper care, the Loaded Injector Noid Light is bound to give many years of satisfaction guaranteed.
Using the Loaded Injector Noid Light
As we saw before, the Loaded Injector Noid Light is used to stress the ECM provided injector pulse circuitry. Here are a few techniques used on the process.
When we use the Loaded Injector Noid Light, there are two possible scenarios. One, is that the Loaded Injector Noid Light pulses fine, in which case the issue is in the injector itself, either clogged or it has an open circuit coil. Two, is that the Loaded Injector Noid Light does not pulse or blink when the engine is cranked. Remember, you disconnect the injector and substitute or connect the Loaded Injector Noid Light in place of the injector. So, if no pulse is seen, then here are ways to identify the source of the trouble. Scenario one. Determine power feed current flow supply. You could have an issue with the 12 volt feed, and still a normal noid or volt-meter would still show a lit or 12 volt reading, as if nothing’s wrong. Therefore, connect one side of the Loaded Injector Noid Light to the injector power feed wire, and the other side to a good ground. The Loaded Injector Noid Light will load the circuit. If you see it lit, there are at least 1.2 Amps flowing, in which case power feed is fine. Scenario two. Determine if the ECM is providing a good ground pulse to the injector. The ECM pulses and grounds the injector to supply fuel during engine operation. If the ground provided by the ECM is faulty or weak, a regular test light, noid light or volt-meter will show no issues. But, the Loaded Injector Noid Light will definitely fail to light up if there’s a circuit issue. So, connect the pulsed wire of the injector to the Loaded Injector
Noid Light, and the other side to battery positive. Crank the engine, and you should see a strong pulsing Loaded Injector Noid Light. If not, then let’s continued tracing the issue. Scenario three. Determine if the issue is at the ECM ground or the ECM driver transistor itself. Leave the Loaded Injector Noid Light connected as it were, then remove the ECM connector, and jump the injector wire to the different ECM ground pins. It is impossible to know which of these grounds is used for the injector. So, the quickest and most complete test is to test all grounds. If no joy on the Loaded Injector Noid Light, then trace and repair the ECM grounds. If the Loaded Injector Noid Light lights up, then issue is with the ECM itself. Make sure that the ECM is not in injector cut-off, due to overheating or some other issue. If that’s not the case, then the ECM injector driver transistor or circuit is gone. Replace it or replace the ECM. The Loaded Injector Noid Light, used properly will prove and detect all sorts of injector issues, and provide you with years of satisfaction.
5 Volt Reference Simulator
Almost all sensor circuits on a modern automobile operate on 5 volts reference. A few other crank and CAM sensors do work on 7 and 8 volts, but these are the very few. The 5 volt reference feeds the throttle position, MAP, CAM and crank, wheel speed and vehicle speed sensors, just to name a few. Often times the ECM 5 volt reference circuit either shorts out or simply gets damaged. When this happens, all the sensors are rendered inoperative. The result is that the ECM issues a multitude of codes related to all the sensors, when in fact it’s the 5 volt reference that one with the real issue.
The 5 volt reference simulator gadget seen here, is a small device, and fit for any automotive diagnostic thrown at it. You use it in place of the 5 volt reference. The 5 volt reference can be down due to an ECM circuit faulty, or because a sensor is shorted, also taking down the 5 volt reference. Here’s how this gadget works. Disconnect the faulty 5 volt reference wire coming from the ECM, right at the ECM connector. This wire should not be reading 5 volts, due to the present issue. Use a wiring diagram to identify the ECM 5 volt reference wire. The 5 Volt Reference Simulator gets connected to the battery voltage, therefore, it also shares the same ground as the ECM.
The circuit is very simple, it uses a MC7805CT regulator chip. This chip can do over 1 Amp of current, which is enough for any sensor job. There are two small 0.33 and 0.1 micro Farad capacitors, at the input and output respectively. The out also employs two resistors in series, a 50 Ohm and a 1 Mega Ohm. The 1 Mega is in parallel to the output load to create the 5 volts needed. The 50 Ohm resistor, acts as a current limiter, in case the load, as in a particular sensor, is shorted to ground. In this case, the maximum output current would be more like 252 milli Amps, or way below the maximum supported by the MC78 05 regulator chip.
Finally, it’s worth mentioning that the 5 Volt Reference Simulator has a biasing diode, which is there in case you flip or cross connect the gadget at the battery. The other two remaining components are, the 1 K resistor and LED in series. They’re only there as a turn On signal, so that you know the unit is connected.
There are a few ways to use this handy gadget, but more on this later. This gadget can make the difference between falsely replacing an ECM, or pinpointing the exact problem.
Using the 5 Volt Reference Simulator
The techniques for using the 5 Volt Reference Simulator are varied. In essence, you simply disconnect the 5 volt reference close to the ECM connector, or as close as possible. You may have to cut the wire, then splice it back together again. The idea is to substitute the faulty 5 volt reference from the ECM, with the 5 Volt Reference Simulator output. As you saw before, the 5 Volt Reference Simulator gadget has an internal 1 Mega Ohm resistor. This allows any sensor to make use of the 5 Volt Reference Simulator as if it were the ECM itself. Here the different scenarios for connecting the 5 Volt Reference Simulator. Scenario one: Attach the 5 Volt Reference Simulator to the vehicles electrical system. Disconnect the ECM provided 5 volt reference, and connect the 5 Volt Reference Simulator. This will provide a 5 volt feed throughout the vehicle’s circuit, and to the sensors. Since the 5 Volt Reference Simulator is also connected to the battery ground, you can even start the engine, erase the codes, and review the scanner parameter if so desired. Whenever the ECM 5 volt reference fails, all kinds of codes are set in memory. After the 5 Volt Reference Simulator is in place, codes are erased, and should stay off memory, if there are no other issues. This alone, even of the engine is not started, is one way to prove that there are no issues with the sensors.
Scenario two. Use the 5 Volt Reference Simulator on one specific sensor to prove it’s functionality. Say you want to test the T P S or throttle position sensor. Simply remove the ECM provided 5 volt reference wire pin from the connector, and then substitute it with the 5 Volt Reference Simulator output. Right away, you should see the T P S coming back to life. And, you can prove this by using the scan tool and peeking at what the ECM is seeing, which is a varying voltage output.
Scenario three. Use the 5 Volt Reference Simulator to create the crank or CAM sensor signal to be able to start the vehicle. This will only work if it is a Hall Effect or 3 wire
sensor. These 3 wire sensors have a power feed terminal, a ground, and a signal wire. This is where the 5 Volt Reference Simulator is king. It is designed to be able to act like a signal feeder. So, leave the Hall Effect sensor connected, then connect the 5 Volt Reference Simulator to the signal wire. The signal wire also is a 5 volt reference, which the Hall Effect sensor toggles to ground. Because of the 1 Mega and 50 Ohm resistors, the 5 Volt Reference Simulator voltage is also toggled to ground by the sensor. In other words, it is alright to short the 5 Volt Reference Simulator voltage to ground. This is a unique feature, not fould on many 5 volt simulators meant for electronic purposes. This circuit was developed from the ground up for automotive purposes. If you’ve already replace the crank or CAM sensor, and your issue is in the ECM provided signal bias 5 volt reference, then the engine should be able to start now. This will prove that the issue is at the ECM or wiring, not the crank sensor itself. There are many other ways to use this gadget. With good care, the 5 Volt Reference Simulator should prove useful for many years to come.
Parasitic Draw Amp Meter
How many times have you seen the battery of your car discharge overnight, and found out how hard is was to pinpoint the exact cause of the current draw. Well, don’t despair, the Parasitic Draw Amp Meter is here. This is a very sensitive gadget. So, be advised that the Parasitic Draw Amp Meter will fluctuate it’s needle from the slightest current flow. The techniques on how to use this gadget will be shown later. But first, a word on parasitic draws. A parasitic draw is when the car is shot off, and yet there is still an excessive current flow from the battery. Modern automobiles, since loaded with many onboard computers, tend to draw some power even when the engine is off. As a rule of thumb, an 20 milli Amp or higher current draw will drain the battery overnight. Other publications may state a higher current draw, but we’ve seen over years of testing that 18 to 20 milli Amps is the threshold for battery drain. This does not apply to the Toyota Prius, which has a very high current drain. In fact, it is recommended that you disconnect it’s small 12 volt battery if your Prius is left to stand more than a week to keep the charge.
Automotive parasitic current draw is always the result of a component that’s left turned on, or a short to one of the circuits, as in a shorted module or computer that won’t shut off. Don’t ever remove fuses to be able to find a parasitic draw, or you’ll be a very confused person. Modern vehicles computers take up a while to reset or boot up themselves. On some models as much as 45 minutes. You don’t want to wait that long every time you unplug a fuse. So, do not unplug or remove fuses when tracing a parasitic current draw. The process to trace or find the source of a parasitic draw is straightforward. You need three things, a wiring diagram, the Parasitic Draw Amp Meter here, and common sense. First, zero out the Parasitic Draw Amp Meter using it’s zero potentiometer. Start by removing the negative battery cable from the battery post, then connect the Parasitic Draw Amp Meter in series with the removed battery cable. The idea is for all the current feeding the different computers or modules to have to go through the Parasitic Draw Amp Meter. Remember, turn all loads and the ignition switch off before starting this procedure. After connecting the Parasitic Draw Amp Meter, wait until the current draw stabilizes itself. As we’ve said, it may take as much as 45 minutes. When this happens, you’ll see the needle stops fluctuating and stay at rest. Whatever you see at the needle, multiply times 10. The Parasitic Draw Amp Meter is a 10 to one circuit. In other words, it amplifies the input 10 times. The Parasitic Draw Amp Meter works as follows.
The circuit uses a 741 Op Amp to do the amplifying. The 741 Op Amp is a very common I C chip readily found anywhere. Use a universal PC Board to solder the 741 Op Amp to it, also found at any electronics parts store. A 10 Kilo Ohm potentiometer is also used to zero out the gadget when disconnected, and no current flows through it. A few diodes, D3, D4, D1 and D2 are used to guide the current and protect the Op Amp and Amp Meter. A 1 milli Amp meter is also used to serve as the signaling device. The meter is a 3 dollar component, also found at any electronics parts store. This entire gadget can be built for under 14 dollars. There are some laboratory level, low current Amp Meters, but these cost a lot of money. The Parasitic Draw Amp Meter is at this time your only option.
The Parasitic Draw Amp Meter is powered by two 9 volt batteries. The reason is that it also checks negative current draw. But why? Why would you want that on a 12.6 volt DC automotive system? The answer, is loss of ground. In the event of a loss of ground, things will get dicey, and you may see negative current flow, which will never register on a normal digital DC Amp meter. 99% of all digital Amp meters are unreliable when reading low current or parasitic draw. A clamp-on Amp probe may also be used, but only as a preliminary measurement, due to unreliable readings. So, the Parasitic Draw Amp Meter is a very sensitive low current Amp Meter, and also a ground issue detector.
Last, it’s the R5 resistor. This is a 1 Ohm, very important resistor. In essence the Parasitic Draw Amp Meter is a voltmeter, made to measure Amps depending on the voltage drop across R5. We recommend a military specification resistor, since they’re more accurate. R5 color code is also odd, at Brown, Black, Gold and Gold. The last color can be White, which makes a tolerance of 2%, gold is 5%. Regardless, concentrate on the first three colors.
The Parasitic Draw Amp Meter has a maximum needle fluctuation of 100 Milli Amps. So, subdivide the meter scale accordingly. Half the needle scale is 50 Milli Amps, one quarter is 25 Milli Amps, and so on.
Basically, input current flows from negative, through the 1 Ohm R5 resistor, and it’s output is fed into the 741 Op Amp chip. The reading input at pin 3 is amplified, and the 741 Op Amp output is fed to the Amp Meter needle. At this time, you must have zeroed out the Parasitic Draw Amp Meter, and if you’re getting a higher than 20 Milli Amps reading, you’ve got a parasitic draw. If your needle moves backwards, you’ve got a ground issue. Fix that first, then proceed. The Parasitic Draw Amp Meter is protected by diodes and an electronic circuit breaker. This is probably the hardest part to get, but here, we’ve done the work for you so far as part number is concerned. You also get an On and Off switch, and an LED On indicator. Finally, there’s an ingenuous PC Board mounted buzzer, and relay section made to sound off a major short. The buzzer and relay are inside the enclosure. If your Parasitic Draw Amp Meter breaker trips right away, then your issue is a major short, not a parasitic draw. In this case, the buzzer will also start sounding, indicating that the circuit breaker has tripped and there’s a major short. Do not use the very sensitive Parasitic Draw Amp Meter to trace major shorts. Use a normal digital Amp Meter instead. With good care, the Parasitic Draw Amp Meter will last you for many years to come. Using the Parasitic Draw Amp Meter
Previously, we explained the construction of the Parasitic Draw Amp-Meter. We will now explain how this tool can be used to it’s maximum ability and different uses. For the record, you will need three things, a wiring diagram, the Parasitic Draw Amp-Meter, and common sense. To use the Parasitic Draw Amp-Meter, you must remove the positive or negative battery terminal, and connect the unit in series with the rest of the electrical system. We’ll use the positive side in our diagram, but ether one is fine. In this way, any and all flowing electrons will have to go through the Parasitic Draw Amp-Meter. As soon as this happens, current flowing through the 1 Ohm resistor will register at the meter needle. Once connected, the Parasitic Draw Amp-Meter’s needle will start fluctuating a bit. This is the result of the different modules powering On, Off and then going to Standby. Do not disconnect and re-connect fuses randomly. This will only reset the modules or computers. Some of these may take a long time to go into standby.
Unless you see the Parasitic Draw Amp-Meter go to 20 milli Amps or less within 2 to 5 minutes, wait about an hour for the modules to go into standby and the needle to stabilize. If after an hour, you still see a current draw higher than 20 milli Amps or so, then you have a battery draining current draw. Then, proceed as follows, using the wiring diagram for Power Distribution, easily accessible, at Alldata or Mitchell-1, start disconnecting each section specific fuse. One fuse normally feeds a few modules or components. We’ve said not to disconnect and reconnect fuses. Here, we’re only disconnecting the fuse, not re-connecting it. If any fuse is reconnected, then the respective modules wake up and start consuming power, skewing your diagnostic. So, for now, disconnect the fuse only. As soon as the culprit area is disconnected, your Parasitic Draw Amp-Meter will drop its needle. This is your clue of the general area for the faulty component. At this time, review the “Power Distribution” wiring diagram. Look at what the fuse is feeding. Then, here’s the catch, reconnect the fuse, wait for things to settle, and proceed to only disconnect those components or modules in the fault fuse circuit. This is why this type of work takes some time to perform. So, to resume the procedure, you only disconnect and reconnect twice. The first time when disconnecting the battery, and the second time when you disconnect the fuse and the needle drops. That fuse is reconnected. Then, proceed to only disconnect the components tied to that fused circuit. As soon as the faulty component is disconnected, you’ll see the needle drop and you would have found your issue and problem solved. This is one way of using the Parasitic Draw Amp-Meter. Another way is to also connect the Parasitic Draw Amp-Meter to one component only. Some components operate on current only, not voltage, such as today’s Air Fuel Ratio sensors, or Wide Band Oxygen Sensors. For the first time, anywhere on the Web or in any book or publication, we’ll show you how to test the Air Fuel Ratio sensor, using the Parasitic Draw Amp-Meter. You start by connecting the unit in series with the Air Fuel Ratio sensor. But, more on that later. Suffice it to say that you always connect the Parasitic Draw Amp-Meter in series, and if you draw excessive current, the breaker will trip, and the buzzer will sound off. With some dedication and training, the Parasitic Draw Amp-Meter will prove useful for many years to come.
Fuse Voltage Drop Short Identifier
The Fuse Voltage Drop Short Identifier is simply a very sensitive volt meter. This unit is used mainly to do a voltage drop across very small electrical loads. They may include the alternator wire, which prevents the battery from being charged, and doing a voltage drop test across individual fuses. If doing a fuse voltage drop test with the Fuse Voltage Drop Short Identifier, then you’ll need our special voltage-to-amperage chart, available here. The Fuse Voltage Drop Short Identifier, works in conjunction with a 10 Ohm resistor. The resistor, right at the gadget’s input, drops the actual voltage. Then, the voltage dropped is fed to the 741 Op Amp input. The Op Amp also has a 10 K Ohm variable resistor for the zero function, and its output is fed right to the needle volt meter. The gadget uses a dual 9 volt battery power feed input. The dual power feed is meant for negative values, in case there’s an issue with the ground. If this is the case, the current flow with often reverse itself depending on the ground potential. This unit can be built for under 12 dollars. The Fuse Voltage Drop Short Identifier has an On switch, and an LED indicator to note the On position. It is protected by diodes D1 through D4 at the inputs. The 10 Ohm input resistor draws a maximum of 1.5 Amps at 14.7 volts, not enough to cause damage even if it is a dead short. The reason why this resistor is so small, is to raise the sensitivity of the volt meter. The 10 Ohm resistor should be a ceramic type resistor, with a heat sink to it.
This unit is meant to measure small parasitic voltages, and with enough care, should last you a very long time.
How to Use the Fuse Voltage Drop Short Identifier
Okay, I would like all of you now to consider one wonderful idea. One idea that may save all of you time and money. An idea, developed over many months, and with one specific goal in mind.
How do we find an automotive short, in the fastest way possible? And, How do we do this, without disconnecting anything at all? Well, this is the very first article of it’s kind. The voltage charts in here, as well as the equipment, was developed over many months, and doing the required research and development. So, here we go.
The Voltage Drop Short Identifier is both, a gadget and a research chart to be able to find short circuits in a modern automobile. In today’s automotive world, you can not disconnect and reconnect fuses and modules to find electrical short. Every time a module is disconnected, it’ll do a re-boot, which may take a long time to complete. Meanwhile, while re-booting it’ll draw some current skewing your diagnostics. With the Voltage Drop Short Identifier, you can detect faint voltage drops without any disassembly. The Voltage Drop Short Identifier is nothing more than a very sensitive volt meter, made for the exact purpose of doing voltage drops across fuses. A normal voltmeter is fine, but only if the short is large enough. Most digital voltmeters are not accurate in the low milli volt range. The inexpensive Voltage Drop Short Identifier can do it all. It can find parasitic current draws, tiny shorted components in the 2 to 10 milli Amp range, faulty modules that stay awake all the time, draining the battery. The Voltage Drop Short Identifier is used with our provided voltage drop chart. You need to understand that the chart, provides a way to convert voltage drop across a fuse, into a current value. In other words, each fuse is like a straight wire. However, all conductors do
have tiny resistances to them, in the milli Ohm range. These small resistances are impossible to measure using normal Ohm meters. So, the only way to see if a fuse is On, or conducting electrical current, is doing a voltage drop test, with a very sensitive volt meter, which is why the Voltage Drop Short Identifier is needed. You may use a laboratory grade volt meter, but be prepared to shell out lots of money. A normal digital Ohm Meter is not sensitive enough. There are older analog volt meters, like the Simpson 260 voltmeter that may also do the job, but they’re not cheap. So, to use the Voltage Drop Short Identifier, measure across the fuse. Remember, each type of fuse has a specific characteristics. So, a 10 Amp mini fuse, at 10 milli volts, will mean a different current flow than a 10 Amp Maxi fuse, also at 10 milli volts. In other words, the value of this technique and the Voltage Drop Short Identifier is in also using the chart provided here, to determine current flow. Once you’ve determined the voltage drop across the fuse, compared it to the chart, then determine if it’s higher than 10 milli Amps or so. The entire car can not have a combined current draw higher than 20 milli Amps or so. Most fuses will have zero, or no higher than 3 milli Amps of current flowing through them. Most small, battery draining shorts, will raise current consumption higher than 35 milli Amps. As soon as you see 18 milli Amps or higher in one single fuse alone, you’ve found your troubled circuit. Then, follow a power distribution wiring diagram, and start disconnecting every component that’s connected to that fuse. Disconnect and leave disconnected. Do not reconnect again. As soon as the culprit component is disconnected, your Voltage Drop Short Identifier reading will drop and issue solved. This technique was brought to you only in here, and seen nowhere else with our fully researched fuse voltage drop chart. Our chart was developed by first using a high resistance rheostat as a load, and measuring voltage drops across all the different types of fuses, together with the fuse box and wiring harnesses. We acquired various wiring harnesses from local salvage yards, and finally double checked the numbers using various vehicles over many months. Our chart is solid and very reliable. As a final note, it is worth mentioning that even after you’ve found your shorted component, it is advisable to also connect an Amp Meter in series, and double check the issue. This is simply an insurance against replacing any good component. And, with proper care, the Voltage Drop Short Identifier should last you many years to come. Found here, is the Volts-to-Amps chart as developed by us over many months of testing. Hopefully, it’ll serve you well.
Ignition Primary DIS - COP Probe
It is hard to believe, why tool and equipment manufacturers, haven’t made an effort to make a viable and useful DIS Distributorless Ignition System, or COP Coil-On-Plug probe, like the Ignition Primary DIS - COP Probe. The reason is probably because it can be built inexpensively, and therefore, their profit margins wouldn’t amount to much. Now, to shed some light on the subject. All forms of distributorless ignition systems, whether coil on plug or waste spark systems, employ separate ignition coil circuits to fire the spark plugs. In most modern engines, DIS has given way to the coil per cylinder system, called, Coil-On-Plug. With the distributor gone, which was a mechanical device, it is now easier to acquire ignition signals.
Or, is it really? Well, maybe not. The problem is that coil on plugs are buried deep in the cylinder head. Access to the secondary is now a major issue in misfire diagnostics. However, the Ignition Primary DIS - COP Probe is here to save the day. But, before we go into it, you need to understand one fact. On ignition coils, the secondary is the high voltage spark carrying circuit, but, the primary, which is actuated by the ignition module, is a mirror image of the secondary. So, again, the primary, is a mirror image, of the secondary. You don’t need to access the secondary at all to get an ignition waveform.
The Ignition Primary DIS - COP Probe works as follows. Input protection diodes D1 through D12 are connected to the coil primary pulsed side. This is the side being pulsed to ground by the module, or as it is done now, by the ECM. Because of the way the diodes are connected, there is no cross connection at all. So one coil primary will not trigger the other. Afterwards, the inputs at the other end of the diodes are tied together, and fed to a resistor voltage divider network. Remember, this is a 10 to 1 reduction gadget. Most ignition primary voltages, can go as high as 80 volts or more. The Ignition Primary DIS - COP Probe will drop this voltage down 10 times. So, when reading the oscilloscope waveform, take that into account.
We’ve made no attempt here to clip the ignition inductive kick. What you’ll get is a clean, unadulterated ignition waveform. And, it’ll give you many years of service. Ignition Primary DIS - COP Probe
How to Use the Ignition Primary DIS Probe
Using the Ignition Primary DIS Probe is a very straight forward operation. As we’ve said before, the primary of the ignition coil is a mirror image of the secondary. So, a misfire will also reflect on the primary, and be able to be picked up by the Ignition Primary DIS Probe.
Connect each of the alligator clips of the Ignition Primary DIS Probe to the pulsed side of each ignition coil. Remember that the coils are not going to be triggered all at the same time. So, when we connect the oscilloscope to the Ignition Primary DIS Probe, each coil pulse will arrive one after the other. Most scopes have 2 input channels. Connect the Ignition Primary DIS Probe to channel 2, and use channel 1 as a cylinder 1 synch. In other words, you’re going to synch the ignition pulses to channel 1 or cylinder number 1. All you need to do then is figure out the firing order for the engine you’re working on, and voila, you now have a complete ignition analyzer at a fraction of the cost. Any modern digital D S O or digital storage oscilloscope, can be turned into a full fledged ignition analyzer. If you want to get fancier, a future specifications, cylinder, and firing order Android App will be available.
So, here’s a little bit more insight on using the Ignition Primary DIS Probe.
First, after connecting the Ignition Primary DIS Probe, you need to find out which is cylinder 1. This is normally identified by determining the cylinder head closer to the front, on a V type engine. On that side, the front most cylinder is number 1. Use channel 1, and connect to cylinder 1 primary. That’ll be your synchronization pulse. To read the ignition pulse, you need to analyze three points on the waveform. One, the firing line also called the spark line. This line happens after the ignition On pulse. It is the result of the magnetic field collapsing on itself. It should reach at least 40 volts, signaling good spark reserve. A good waveform library is a must. The left edge of the firing line is the ignition pulse turn Off point. Make sure it’s clean. If not, it points to a faulty ignition driver transistor. Two, the spark duration line, which proceeds the firing line. This measure says exactly how long the spark endured. It is an indication of the condition of the ignition components, such as plugs, wires or boots, and even the coil itself. This line also says a lot about the air-fuel mixture, whether it’s lean or rich. Finally, the ignition pulse turn Off and oscillations. The turn Off point, gives you the relative condition also of the ignition parts. It should be fairly clean and sudden.
There is an ocean of information that can be extracted from the ignition primary
waveform, enough for a whole book on the subject. The important thing is that you don’t have to spend lots of money to be able to diagnose a misfiring problem. All scopes, with the aid of the Ignition Primary DIS Probe can capture ignition waveforms, which by the way, is by far the only way to properly diagnose an ignition system. With proper training and care, the Ignition Primary DIS Probe will give you lots of satisfaction at jobs well served, and years of service.
Drive-By-Wire Motor Actuator Controller
WARNING, WARNING, WARNING. DO NOT use the Drive-By-Wire Motor Actuator Controller with the engine On. The Drive-By-Wire Motor Actuator Controller is meant to be used with Key-On-Engine-Off. Any other use is at your own risk.
Gone are the days when the throttle was controlled by a cable. The throttle cable has been omitted, in favor of the throttle actuator or drive-by-wire throttle control. The vast majority of throttle actuator control motors are the DC duty cycle control type. In other words, the ECM controls a two terminal DC motor, by way of a duty cycle signal. On duty cycle signals, the frequency and voltage remains constant. What changes, is the positive crest of the waveform. This means that on a square wave, the positive crest changes width. The wider the positive width, the wider the throttle actuator opening. In today’s throttle control diagnostics, it is important to be able to actuate the throttle for various reasons. We’ll go deeper into using this gadget later. But, suffice it to say that, the Drive-By-Wire Motor Actuator Controller is used to diagnose the multiple throttle position sensor inputs, to clean the throttle body, to determine if motor is binding and to diagnose any of dozens of issues with an electronic throttle actuator system.
But first, a word on how the electronic throttle works. The throttle plates are always being forced down by an internal spring. This spring and gear mechanism can start to bind from wear and tear. If that happens, the ECM goes into limp in mode, reduces injection pulse, and turns the engine into a virtual lawn mower. It doesn’t matter if the throttle sticks in the open position. With injection cut off, your car isn’t going anywhere.
The Drive-By-Wire Motor Actuator Controller creates the duty cycle control signal to act against the spring load. So, in slow motion, the pulse pulls open the throttle valve, then it supposedly closes again due to the spring action, then the second pulse pulls it open again, and it closes again. But, in reality this happens so fast, that the throttle valve stays open a specific amount of degrees. The wider the duty cycle pulse, the wider the opening. The Drive-By-Wire Motor Actuator Controller works as follows.
The whole Drive-By-Wire Motor Actuator Controller is centered around the SG3525 micro circuit. This is a pulse width modulation chip. It is used by many automotive and industrial manufacturers for controlling motors. The SG3525 then controls the base of the transistor, BUK9535-55 MOSFET driver. The transistor controls the throttle motor itself, depending on the aperture control. The Drive-By-Wire Motor Actuator Controller also has minimum and maximum controls. These are set once, and control the lowest and highest duty cycle possible. Most drive-bywire motors don’t work well below 20%, hence this control is set to provide a minimum. You also don’t want to feed 100% duty cycle to the throttle motor all the time, which can
cause it to fail. Finally, there’s a frequency control as well. This control you also set only once. Remember, duty cycle has nothing to do with frequency. On electronic throttle control the frequency stays constant, or at about 200 to 400 Hertz. This control is set only once and
then left alone. All the aperture is done with the aperture control, which varies the output from the minimum and maximum, according to these said controls. We’d like to reiterate the previous warning. DO NOT use the Drive-By-Wire Motor Actuator Controller with the engine On. The Drive-By-Wire Motor Actuator Controller is meant to be used with Key-On-Engine-Off. Any other use is at your own risk. The Drive-By-Wire Motor Actuator Controller is a sturdy and tough unit, which will give you many years of service.
How to Use the Drive-By-Wire Actuator Controller
One of the main issues with a Drive-By-Wire electronic throttle is the dual or triple TPS, throttle position sensor. The TPS potentiometer, by definition develops blind spots in its carbon tracking. The whole issue is exacerbated by the fact that on Drive-By-Wire Actuators, the TPS sensor is a dual or triple unit. The idea for it, is that the ECM is constantly comparing the multi TPS signal. If the unit develops a fault, then the two readings will not correspond, and a faulty code is issued.
Here’s how to use the Drive-By-Wire Actuator Controller to detect TPS issues. Connect a Graphing Voltmeter to the Drive-By-Wire Actuator TPS. This is a multi TPS sensor so, use channels 1 and 2. Set the voltmeter to a maximum of 5 volts. Disconnect the Drive-By-Wire Actuator motor connector, and connect the Drive-By-Wire Actuator Controller.
Slowly work the aperture control potentiometer. Operate the control from full closed, to full open, and do so without a hesitating movement. The idea is to swing the Drive-ByWire Actuator Multiple TPS to detect any blind spots in the read out. As you can see, you’re using the ECM 5 volt reference, and the Drive-By-Wire Actuator Controller to actuate the electronic throttle motor. The output signal should be as follows. Assuming it is a dual TPS, most of them are, you will see two mirror, but inverted TPS signal sweeps. This is the way it should be. What you’re looking for are small signal drops, which are indicative of a blind spot. Blind spots are sometimes not recognized by the ECM. This problem usually develop hesitation during acceleration and bucking. This procedure is also doable with key on engine off, and a second person actuating the throttle. As you can imagine, the human foot will never be as accurate in performing a signal sweep as the Drive-By-Wire Actuator Controller. The Drive-By-Wire Actuator Controller, can also be used in many instances, where there is a need to do a visual inspection of the electronic throttle, and during cleaning of the throttle plates. This tool is at the cutting edge of today’s auto diagnostic equipment world. With proper care, the Drive-By-Wire Actuator Controller will provide you with flawless service.
Ignition Key Transponder Detector
Modern automotive anti-theft systems, use a coded ignition key to authorize the engine turn on. In most cases, another module or computer, such as the ECM, Body Control Module, or the Instrument Cluster Module, serves as the actual anti-theft module. The way the anti-theft systems works is through an ignition key transponder.
The ignition key transponder is embedded inside the back or plastic side of the ignition key. It is a non battery operated circuit. This circuit is powered by an induction coil, that generates a current in the key transponder coil itself, which powers the signal code generation circuit. The code is then received by the anti-theft module, and an OK command is then issued for engine start. Now that we’ve given a brief overview of the circuit, we present here, the Ignition Key Transponder Detector. Well, you might ask, why do we need this Gadget?
The answer is simple, because it allows you do know if the key transponder itself is working, tells you if a new key is not a fake, and will even decode the passkey code, and show you as an oscilloscope waveform.
Here, is how the Ignition Key Transponder Detector works. The Ignition Key Transponder Detector works in the 120 to 135 Kilo Hertz frequency range, and is built around only two micro circuits, a 74 A C 04 and a 74 H C T 74. It also employs a 690 milli Henrys coil, that you can wind yourself using transformer wire. The first part of the circuit is the oscillator that excites the Ignition Key Transponder’s internal coil. This action induces a current to power the Ignition Key Transponder chip. So, power goes from the Ignition Key Transponder Detector coil to the Ignition Key Transponder coil inside the key plastic backing. Once the Ignition Key Transponder is activated, it’ll send the pass code, which is then detected by the Ignition Key Transponder Detector.
So the Ignition Key Transponder Detector coil sends power, and detects at the same time. The second part of the circuit, filters out all the hash from the power generation part and carrier wave, and only leaves the pass code. At this point, you can feed the detected code to an oscilloscope and have a clear waveform view of the actual pass key code. You’d have to freeze the actual waveform to view the fast moving digital code. Then, the pass code is also fed to the 74HCT74 micro chip to drive the green LED. This last part of the circuit simply receives the digital code, senses the positive peaks of the square wave, and drives the LED. For all practical purposes, you don’t need an oscilloscope. Just put the key close to the 690 Milli Henry coil, seen here with red arrow, and watch the LED blink. If it does, then it is a true Ignition Key Transponder key, and not a fake. Many people are being duped by unscrupulous vendors of so called, legitimate ignition transponder keys, which are really empty shells. It is a regrettable fact, but the Ignition Key Transponder Detector will tell you the real story. We’ll later learn how to use this gadget. But, for now, know that the Ignition Key Transponder Detector will serve you well for many years to come.
Using the Ignition Key Transponder Detector
We’ve already explained how to build an Ignition Key Transponder Detector. Now let’s explore the need for this gadget and how to use it. Have your ever wanted to bypass your anti-theft system? Ever lost your car’s ignition key and had to buy, cut, and reprogram your new key? What if your vehicle won’t accept the new key? What if the new key is fine, but your car still won’t start? Well, the issue can be traced to a few problem areas. But, if you can’t determine the operation of your key, you’re done. The only other way is to have a factory scanner, but these are thousands of dollars, and out of reach for most repair shops and Do-ItYourselfers. Here are the possible problem areas, and how to go about repairing them. In order to do a proper anti-theft diagnostic, do the following.
First, determine if the ignition key is working. 90% of consumers replace the ignition key, have it cut, to later find out that the key is not the issue. Use the Ignition Key Transponder Detector to verify the key transponder. If the green LED starts blinking, you’re fine. If not, replace the key. It is common to also purchase an ignition key, to later find out it’s a fake. A key without a transponder will never work.
Another use for the Ignition Key Transponder Detector is that of adapting another key cylinder to the car. Here’s how, let’s assume that you current ignition cylinder coil or key is faulty, and that you manage to purchase a used cylinder and keys, from a local salvage yard. The first use of the Ignition Key Transponder Detector is to determine if the salvage yard keys are operational. If so, then you’ve got a done deal. You don’t have to cut keys and all your components are there. Almost always, these parts are not sold because people don’t know if the system works. The Ignition Key Transponder Detector tells you all you need to know. Yet, another use for the Ignition Key Transponder Detector is to match a key to your car. For example, lots of technicians manage to start a vehicle with a new key taped to the back of the valet or metal only key. This is done just to check the anti-theft computer, and see if it takes a new key program. However, most shops or locksmiths have a few of these blank keys laying around for testing. With the Ignition Key Transponder Detector, you use the scope waveform feature, capture the digital pass code signal, and use it for future reference.
Later on, just compare whichever key you think you matched to the car, and proceed from there. The Ignition Key Transponder Detector, can also be used by locksmiths and salvage yards to detect operational keys to be sold as a complete package, with the ignition key and cylinder.
Finally, the Ignition Key Transponder Detector can also be used to do a bypass of your vehicle’s anti-theft system. It won’t help a thief steal a car, but some car owners don’t really care for this system at all. To do a bypass, record or capture the pass key code using the oscilloscope. Then, use a programmable signal generator, which is a simple chip box, that accepts a recorded digital code. Attach a 690 milli Henrys coil to it, and tape the coil to the inside of the ignition key coil or close to it. Now, every time you insert and turn your ignition key on, it’ll power the code box, transmit the store code to the car ’s anti-theft system, and you vehicle will start. This process is too involved to be useful for a car thief, but works well with the consumer that don’t care for anti-theft systems. Simply put, the Ignition Key Transponder Detector will give you it’s worth for years to come.
Magnetic Sensor Induction Simulator
Have you ever had a case of an engine no start, and realized that the crank sensor was buried under the vehicle, with a hard to access connector? Or did you ever drained the battery cranking the engine, in trying to get a camshaft or crankshaft position sensor signal?
Well, the Magnetic Sensor Induction Simulator is here to the rescue. The Magnetic Sensor Induction Simulator is a very simple, but effective tool. All it does is induce a voltage at the CAM or CRANK sensor, whether it’s a Hall-Effect or magnetic type, meaning 2 or 3 wire type sensor. This principle is exactly how any position sensor operates. On normal operation, position sensors detect the tooth or reluctor wheel rotational speed, and rate of change. In other words, the toothed reluctor wheel induces a magnetic field on the speed sensor, and a voltage is generated at the coil of the sensor. We won’t go deep into the operation of the sensor, as it is covered elsewhere, but this is the basic concept. The Magnetic Sensor Induction Simulator does exactly the same thing. It induces a voltage at the sensor coils, of about 30 Hertz, which corresponds to about 1800 RPM. This is enough the be read at the scan tool or the oscilloscope, by probing at the ECM wires.
So, rather than being constantly cranking the engine to get a signal, the Magnetic Sensor Induction Simulator allows you to connect the appropriate equipment, point, and press the button. Simply extending and positioning the Magnetic Sensor Induction Simulator coil tip, close to the speed position sensor, and pressing the button is enough to induce a signal at the sensor. This is all provided the sensor is working properly. This task has often been done using an electronics soldering gun, but the Magnetic Sensor Induction Simulator is better suited for the task.
Here’s how the Magnetic Sensor Induction Simulator works. The Magnetic Sensor Induction Simulator employs a 10 to 1 power transformer. This is the same transformer type found at any electronics store used to bring down wall outlet power from 120 volts to 12 volts. Any small transformer will do. Then, the 12 volt alternating current is fed into the rectifying diode. This is a half wave rectifier, which cuts down the number of oscillations in half. Otherwise, the RPM signal perceived by the sensor would be too high.
A 1 kilo Ohm resistor and green LED is also in series with the circuit, so, that every time the top button is pressed, you’ll be able to see the LED light blink continuously. The top button is rated for 120 or less volts, as it would only be switching the downgraded 12 volts
from the transformer. The entire Magnetic Sensor Induction Simulator is encased in a P V C tubing, with an extended plastic tube and a hand spun wire coil at the tip. A 700 milli Henry coil will do, as any other large wire coil. BEWARE, DANGER, LOOKOUT. The Magnetic Sensor Induction Simulator is connected to the 120 volt wall outlet. Be mindful of the power cord not to get caught in any of the engine’s parts and cause an electric shock. The Magnetic Sensor Induction Simulator is a very simple and useful tool. It is meant to not have to crank the engine continuously when doing engine testing, and will give you a long service life.
Using the Magnetic Sensor Induction Simulator
We already explained how to build the Magnetic Sensor Induction Simulator. Now, let’s explore how to use this wonderful gadget. The idea behind the Magnetic Sensor Induction Simulator is to induce a signal at the CAM or CRANK sensor, without having to turn or crank the engine. This will solve many issues relating to no start diagnosis, such as having another technician inside the vehicle to work the ignition key, or even the time needed to connect a remote start switch. With the Magnetic Sensor Induction Simulator, just point and click. So, here are a few possible scenarios. Scenario 1. Using the Magnetic Sensor Induction Simulator to induce a CAM or CRANK signal. First, we must understand that there are two basic types of position sensors, the Hall-Effect 3 wire, and the Magnetic 2 wire sensor. The first, produces a square waveform, and the said waveform comes right out of the sensor itself. The magnetic sensor produces a sine wave. This is a waveform with rounded edges.
So, then using the Magnetic Sensor Induction Simulator, the distance between the tip of the unit and the sensor can be as close as possible. However, with the 3 wire Hall-Effect sensor, you need to be careful of not placing the tip of the Magnetic Sensor Induction Simulator too close to the sensor. There will not be any damage, but the magnetic induction from the Magnetic Sensor Induction Simulator, may also cause interference at the sensor wire. So, just don’t get too close with the Magnetic Sensor Induction Simulator tip. A few inches, 2 or 3 inches away will do. Use the Magnetic Sensor Induction Simulator, in conjunction with a scan tool, graphing multi-meter, or oscilloscope, even a regular voltmeter set to alternating current will do. Connect the equipment of choice, then point and shoot. Get as close or as far as needed. You’ll eventually develop a feel for this tool. Scenario 2. Use the Magnetic Sensor Induction Simulator to diagnose ABS wheel speed sensors, and transmission vehicle speed sensor. Yes, the Magnetic Sensor Induction Simulator can also be used to force induce a signal on these sensors. It goes the same way, ust connect the equipment, place the Magnetic Sensor Induction Simulator close to the sensor, and press the button.
Rest assured that, if the sensor in question outputs a signal, the unit is fine. Scenario 3. Using the Magnetic Sensor Induction Simulator to test a sensor while hot. Well, most sensors do fail after the vehicle reaches full hot condition. In this case, you’ll have to use a hair dryer to first heat up the sensor. Think of the engine and how hot it gets. Ok, use the same feel and get the sensor nice and hot. Then, use the Magnetic Sensor Induction Simulator, point and shoot. You didn’t have to start the engine, heat it up, or have to employ the help of a fellow tech to do the job.
Scenario 4. Use the Magnetic Sensor Induction Simulator to diagnose intermittent problems. Yeah, that’s right, the nightmarish intermittent problem. In this case, you’ll have to either build the Magnetic Sensor Induction Simulator with a flip on switch, or use a rubber band to leave the button on. Do the same, connect the equipment and key-onengine-off, tape the tip of the gadget at the sensor, or close to it, and leave it there. Most oscilloscopes have a record feature, yet others like the Scope-1, have a beep-to-function feature that alerts the technician when the signal has dropped.As you can see, this tool can
go a long way in helping you determine what’s wrong with any position sensor, regardless of the system in question. Build it, and it’ll give you many years of service.
O2 Sensor Simulator
The O2 or Oxygen sensor is in charge of providing the ECM a measurement of Oxygen content in the exhaust. The ECM then uses said value to control fuel injection pulse width.
To understand the O2 sensor, we must also know the concept of Closed-Loop operation. Closed-Loop in automotive technology terms, is referred to as the closed relationship of O2 sensor voltage, to ECM injector pulse-width control, and then back to O2 sensor voltage. It is much like closed circuit television, where cameras and TV monitors are part of the system. In this case, the sense and control part of the injector, work together to control the air-fuel mixture. In other words, one senses, the other one changes or modifies, and back to the sensing part. It is a known fact that 60% of all vehicle issues are air-fuel mixture related. So, what do you do when there’s a need to tackle a performance issue with your car? Well, you call upon the help of the O2 Sensor Simulator. The O2 Sensor Simulator, is a simple piece of equipment that mimics the output signal of an O2 sensor. It is calibrated to output a complete swing of voltage every 2.5 to 3 seconds, which is perfect for a simulator.
But, you might ask; what can I possibly do by mimicking the O2 sensor signal? The answer is, quite a bit. First, understand that if you just drive the O2 sensor signal low or high, and leave it there, the ECM will switch to limp in mode and completely ignore the O2 sensor.
So, right off the top, the O2 Sensor Simulator prevents the ECM from taking over and screwing the diagnostics. The wide uses of the O2 Sensor Simulator will be discussed later. Here’s how the O2 Sensor Simulator works. The O2 Sensor Simulator is based on the popular 555 timer integrated circuit chip set.
This is a 50 cent micro chip. All of the circuit can be built for under 8 dollars. The circuit is very simple, it is divided into two sections, the oscillator support part, and the output signal conditioning part. The O2 Sensor Simulator is a classical a-stable 555 timer oscillator. The gadget works by generating the changing or oscillating O2 sensor signal, which is dependent on the value of the 100 K Ohm resistor on the upper left. The entire circuit draws about 12 milli Amps, and it’s powered right from the vehicle’s battery. The RED LED at the top is an always ON indicator, and also serves as a rectifying diode. The Green LED, is ON, only during the high part of the signal, or above 550 milli volts or so. This is a classical high signal state for any O2 sensor. So, with the O2 Sensor Simulator, you’ll be able to simulate a signal, monitor the output, and fully control the ECM to injector pulse width. The O2 Sensor Simulator is meant to also be used with the scan tool and a form of measuring device, like a voltmeter, scope or graphing meter. The O2 Sensor Simulator is able to help you pinpoint exact issues with all kinds of systems, but more on that later. For now, know that this simple to make tool, will probably become your most used gadget, and give you years of usefulness.
Using the O2 Sensor Simulator
The O2 Sensor Simulator is a very valuable tool when trying to determine all sorts of ECM feedback response. Here are a few use scenarios where the O2 Sensor Simulator is of value. Use it to determine fuel injection feedback, closed-loop operation, fuel related misfires, fuel pump delivery and catalytic converter response. So, here are scenarios in detail. Scenario 1. Determine fuel injection feedback. The idea is to cycle the O2 Sensor Simulator, and see how the ECM responds. You do this operation using a voltmeter, with a duty-cycle setting. So, connect the O2 Sensor Simulator in place of the car’s O2 sensor. Also, connect a voltmeter set to duty-cycle to the injector pulsed wire and ground. This is the most detailed and exact way to determine fuel consumption.
A good rule of thumbs is about 3.9% duty cycle at idle. Do this test always at idle, so as not to upset the air fuel mixture with a high RPM. As soon as the engine has reach operating temperature, the ECM will start to follow the O2 Sensor Simulator. You’ll be able to see how the duty-cycle values also follow the O2 Sensor Simulator readings. If not, then the ECM is not able to keep up. This could be due to a clogged filter, bad fuel pump, ignition or valve timing. The point is that it is confirmation that the issue is an air fuel imbalance. Scenario 2. Determine closed-loop operation. Again, disconnect the O2 sensor and connect the O2 Sensor Simulator to the signal wire. For this procedure, you’ll also need to use a generic OBD-2 scan tool. Go into the PIDs and monitor the fuel-status. It’ll be either OPEN or CLOSED loop. Once the engine has reached operating temperature, and the O2 Sensor Simulator has been cycling for a minute or so, the PID should say closed-loop. If so, then that tells you quite a bit. It says that the ECM has received, and interpreted the O2 Sensor Simulator signal, and it’s reacting to it. In the event that there’s another unknown
issue, such as coolant temperature sensor, mass air flow or even an off specs TPS, the ECM will stay in open loop, often without even issuing a code. This technique says a lot. It says that the ECM is able to command the mixture, that the ECM is i s in control.
Scenario 3. Air-Fuel related misfires detection routine. Yes, many engine misfires are also caused by an imbalanced air fuel mixture. Say for example that there’s a vacuum leak, causing the engine to adjust the Fuel-Trims maximum positive, and masking the issue. In this case, record and erase all codes to reset the Fuel-Trims. Then, connect the O2 Sensor Simulator and idle the engine. In this case, the ECM is going to be fooled by the O2 Sensor Simulator. Simulator. It’ll think t hink that the air fuel mixture is fine. Since there’s a vacuum vacuum leak, it won’t compensate and mask the issue. The end result is a steadily misfiring engine, giving you time to assess the situation and do a diagnostic. Scenario 4. Perform a catalytic converter response test. There are two types of converters. There’s the small baby converter, and the normal under body converter. On the larger under body converter, the rear O2 sensor should never follow the O2 Sensor Simulator signal. Since the O2 Sensor Simulator signal is not affected by outside interference, it’ll be fairly easy to diagnose the issue. On the baby small converters, those close to the exhaust manifold, then use an oscilloscope or graphing meter and measure the front O2 Sensor Simulator and rear O2 sensor signal. There should be at least a 200 milli second lag time between the two changing values. In other words, when the front O2 Sensor Simulator signal goes from high to low, on these converters the rear signal should follow, but at a certain lag time. A lag time less than 200 milli seconds points to a defective converter. And, if accompanied by a code, this is sure confirmation of the fault. You will only see this procedure right in this channel. The procedure was developed a few years back, over many months of testing by Mandy Concepcion and his staff. All these techniques are not too hard to learn, And, with a bit of practice, the O2 Sensor Simulator will serve you for many years to come.
ABS Speed Sensor Simulator
Have you ever had a vehicle, where the ABS is prematurely activated in an intermittent way? And, have you asked yourself, is it the wheel speed sensors, the ABS computer, or another electronic issue with the system?
Well, the ABS Speed Sensor Simulator is here to save the day. In today’s vehicles, the vehicle speed sensor is no longer used. Now, one of the wheel speed sensors is used as an input of vehicle speed. This is done in order to reduce redundant components, which do the same thing. So, when using the ABS Speed Sensor Simulator, remember that it can also be used to diagnose the Vehicle Speed Sensor. The ABS Speed Sensor Simulator is a 4 channel output unit. It’s made with 4 diode isolated channels. This allows you to kill each channel independently, without affecting the other channel.
Here’s Here’s how the ABS Speed Sensor Simulator works.
The ABS Speed Sensor Simulator is based on the ubiquitous LM555 oscillator timer chip. The circuit itself is small, but powerful. It is composed of three sections; the LM555 timer microchip part, the output transistor driver part, and the output signal part. The signal section has an impedance matching and isolation transformer. This in effect isolates the ABS Speed Sensor Simulator from any shorted wheel speed sensor short to vehicle power.
The ABS Speed Sensor Simulator also has a frequency variable potentiometer to adjust the output frequency of the signal. Also, the idea behind the four normally ON output switches, is to kill the signal independently to be able to test the ABS response. But, more on how to use the ABS Speed Sensor Simulator later. The ABS Speed Sensor Simulator allows you to test the ABS and traction control response, without ever leaving the repair shop. Yes, that’s right, just lift all 4 tires off the ground, connect and check. The ABS Speed Sensor Simulator LM555 chip can be found anywhere. The entire ABS Speed Sensor Simulator can be built for less than 8 dollars, making for a very useful piece of equipment that’ll last you for many years to come.
Using the ABS Speed Sensor Simulator
The ABS Speed Sensor Simulator is a useful and versatile tool. It can kill each wheel speed signal selectively. The idea here is to prove that the ABS module, hydraulic pump and solenoids are operational before condemning any of these expensive parts. But, before we start, a word of warning. DO NOT use the ABS Speed Sensor Simulator while the vehicle is moving. This is not a road test equipment, and you’re liable to cause an accident.
The ABS Speed Sensor Simulator is meant to allow you to test the ABS system, without having to go for a road test, which is time consuming. To use the ABS Speed Sensor Simulator, do the following. One. Lift the vehicles 4 tires, and set the transmission in neutral. Remember, all you want to do is perform an ABS actuation, by killing the signal with one of the 4 buttons.
Two. Disable the traction control, which is now part of the ABS system, but will skew your results for the ABS test. Three. Remember, you’ll have to step on the brakes for this test to work. Disconnect all the ABS wheel speed sensors. Then, connect each of the ABS Speed Sensor Simulator output channels to each ABS signal wire. Place the ABS Speed Sensor Simulator on the passenger seat, and set the ABS Speed Sensor Simulator frequency knob to it’s lowest setting. Four. With the car raised from the ground, and secure, start the car in NEUTRAL, not in PARK, and don’t step on the brakes. Why? It’s simple, once the ABS Speed Sensor Simulator is connected, it starts sensing a signal to the ABS computer. When it does, if you start in park, the ABS computer will issue a code, and go into limp-in mode. Simply put, there’s no way that a vehicle in park can have a wheel speed sensor signal. It is called a logic fault, and flagged by the ABS module as a code issuing failure. So, start the vehicle in neutral, it is then Ok for the ABS module to see a wheel speed signal, and we can proceed with the test. Then, let the car idle and set it to drive. Do not accelerate, or step on the brakes. Remember that the brake switch is the only indicator for the ABS to go active.
Five. Now you have the ABS Speed Sensor Simulator connected, the car in drive, the foot off the brakes, and you’re ready to do the test. At this time, slowly raise the frequency knob to a higher setting, or even the highest setting.
To test the ABS system, softly step on the brakes, and then quickly press one of the signal kill buttons on the ABS Speed Sensor Simulator. Right away, you’ll see an ABS actuation. You’ll continue to see an ABS actuation even if the wheels are not rolling, since the ABS Speed Sensor Simulator is acting as a wheel speed signal output device. Every time you step on the brakes, and press the ABS Speed Sensor Simulator kill button, the ABS will then go into action. The ABS Speed Sensor Simulator works, because it creates a signal on all 4 wheels. Without the ABS Speed Sensor Simulator, this is impossible to do with just the car up on the lift. You can even bleed the ABS system, by running a remote brake switch, and using the ABS Speed Sensor Simulator, but more on this later. Now, what did you learn by doing the operation we just explained? Well, quite a lot actually.
For one, you know the ABS computer is up to the task. Two, you also know the ABS hydraulic pump is operational. Otherwise, the ABS will sense a low hydraulic brake fluid pressure, go into limp-in mode, and cancel any actuation. So, now you also know that t hat the ABS hydraulic pressure sensor is fine. fi ne. And three, since you heard all the ABS solenoids clicking On and Off, you know they’re also fine. Otherwise, since the solenoids are nice and hot, the ABS module will sense a short or open signal, and set a code. The ABS Speed Sensor Simulator, can also be used to test the wheel speed sensor wiring harness. In this case, you do the previous procedure, but rather then do a brake pedal actuation, just go around the car and wiggle the wires. Any wiring issues, usually under the body panels, or on a vehicle that’s been in an accident, will become apparent and the ABS module will then issue a sensor specific code. The ABS Speed Sensor Simulator can be used to test many ABS related issues. Some ABS hydraulic pumps, also tend to fail after repeated ABS actuation periods. So, just do a few ABS activations, as mentioned before, and rest assured that hydraulic pump will get nice and hot, revealing any issue. And, all this is done without leaving your home or repair shop. The ABS Speed Sensor Simulator is a versatile tool, with the ability to serve you for many years to come.
ABS Speed Sensor Simulator, Simulator, Bleeding the Brakes
The ABS Speed Sensor Simulator can also be used to bleed the brake system valve body and pump. Yes, that’s right, and you can do it all without the use of a dedicated scan tool. In other words, for those who don’t know, the ABS system has to be bled anytime there was a brake fluid leak, or when the ABS hydraulic valve body has been replaced. For this, you need a factory level scan tool, which will set you back a few thousand dollars.
Well, the ABS Speed Sensor Simulator is here to the rescue. Basically, what you do is actuate the ABS valve body hydraulic unit, and on some systems you may need to crack open the bleeder screws. Most of the times, the trapped air will rise to the surface, and end up at the t he brake pump cylinder reservoir. reservoir. So, here’s how you use the ABS Speed Sensor Simulator to bleed the ABS system.
IMPORTANT NOTE: Please, remember that before you do this procedure, you have to gravity bleed the brakes normally, normally, as you would in a normal situation.
First, connect the ABS Speed Sensor Simulator’s four outputs to the signal wire at each wheel speed sensor. Second, raise the car’s four tires, and start the car in neutral. Please refer to our previous section on using the ABS Speed Sensor Simulator. Third, remove the master cylinder reservoir cap, and leave it off. This is done so the trapped air can rise to the top. Otherwise, the air pocket will not allow the brakes to bleed. Four, without touching the brake pedal, shift to drive, do not accelerate, and press one of the signal kill buttons at the ABS Speed Sensor Simulator. This action will activate the ABS systems, and you’ll hear all the ABS solenoids operating. Do this about 4 to 6 times. Finally, go outside into the engine compartment, and if your vehicle calls for you to crack open the ABS bleeders, do so at this time.
Then again, press the kill buttons a few times, and crack open the ABS bleeder screws. Do not crack open the bleeder screws at the brake calipers. This is the lowest hydraulic point that won’t trap air, besides, you should have done a normal brake bleeding procedure before you started. This procedure is meant to bleed the trapped air inside the ABS hydraulic valve body. By using the ABS Speed Sensor Simulator you don’t need an expensive factory scanner, that will set you back thousands of dollars. When it comes to bleeding the ABS system, this is it, this is exactly what the O E M factory scanner does, when doing an ABS bleeding sequence. Rest assured that the ABS Speed Sensor Simulator will make it worth while for you, for many years to come.
Optical CAM and CRANK Sensor Simulator
Have you ever had an issue with a no start condition, and asked yourself; I wish I had a spare CAM or CRANK sensor to try out? I wish I knew if was the ECM or the sensor itself?
Well, here’s the Optical CAM and CRANK Sensor Simulator to the rescue. Yes, this is a small, simple, versatile, and very ingenious gadget. The Optical CAM and CRANK Sensor Simulator, is capable of simulating any crankshaft or camshaft signal. The one component, that determines the output sensor signal produced by the sensor, is the optical signature diagram. Ok fine, but what is the optical signature diagram? Where can you buy one of these? The answer to that question is simple, you make it yourself. Understand that, what we’re going to show you here, is cutting edge ingenuity. Not because it’s complicated, but because it’s incredibly simple to make, and full of common sense. So, we’ll first show you how the Optical CAM and CRANK Sensor Simulator circuit works; then we’ll delve into the construction of the optical signature diagram. Later on, we’ll then show you how to use the Optical CAM and CRANK Sensor Simulator.
The Optical CAM and CRANK Sensor Simulator circuit, works as follows. The circuit, like many of the circuits in this series, is based on the venerable LM555 microchip. The LM555 is an oscillator chip. It creates a square waveform from the components attached to it. The entire circuit is divided into three parts; the photo electric sensor, based on the EE SB5 from manufacturer Omron, which by the way, it’s a 4 dollar part. Then there’s also the LM555 microchip section, which takes the output from the EE SB5, and acts as a Schmitt Trigger amplifier. A Schmitt Trigger does nothing, unless there’s a considerable change in the input. The LM555 is used so that the Optical CAM and CRANK Sensor Simulator will not output a signal from just random light noise, especially in a repair shop environment. So, for the Optical CAM and CRANK Sensor Simulator to output a signal, the rotational speed of the engine has to be at least 200 RPM. The final part of the circuit, is a simple transistor, feeding a transformer, that changes the square wave output into a sine wave. This is done, for vehicles that use a magnetic two wire CAM or CRANK sensor. If your vehicle uses a three wire sensor, then use the output signal at the top, which is a square wave output.
The Optical CAM and CRANK Sensor Simulator also has an LED for diagnostic purposes, which is used to test the gadget operation. So, as you can see, this is a 15 dollar circuit, encased into a PVC pipe, and using a low cost camera mount, available at any
consumer electronic store. There’s also a camera positioning arm that can be used with the Optical CAM and CRANK Sensor Simulator. More than likely, this camera arm will cost you more than the Optical CAM and CRANK Sensor Simulator itself. But, that is beyond our control.
Ok, now you know the basic operation of the circuit, and building it is a breeze, considering how few components it has. Now, let’s analyze the before mentioned optical signature diagram. The Optical CAM and CRANK Sensor Simulator outputs a high signal state whenever there’s a white or dark mark in front of the EE SB5 optical sensor. So, assuming we use a wheel for explanation purposes, anytime the Optical CAM and CRANK Sensor Simulator sees a white mark, it goes low, and, anytime it sees a dark mark, it goes high. That, is what creates the changing square waveform output. If the output is taken at the transformer, then you see a sine or rounded waveform.
Ok, so what about this optical signature diagram. Well, the Optical CAM and CRANK Sensor Simulator is in effect a universal CAM or CRANK sensor simulator. But, the output signal has to be synchronized with the engine. So, you create a specific optical signature diagram per engine, to give you the exact CAM or CRANK signal signature output. Yes, by simply printing out a marked wheel, you can generate the exact CAM or CRANK signal as the original sensor. To make and use the optical signature diagram, do the following. Let’s consider a CRANK sensor signal as an example. First, you must get the actual CRANK sensor signal waveform from a previous recording, for that exact engine. This is why we’ve always stressed the importance of a waveform database. There are also various publications dealing with waveforms, or even in the internet.
Also remember, you do this only once per vehicle engine size. Here we’ll use a 1989 BMW 325 crank sensor signal signature.
The first thing you do is divide the crank sensor waveform into 360, which corresponds to the 360 degrees of rotation. Then, do the following. Using a black marker and a ruler, draw concentric lines every time you see a signal change, or a wave crest.
Very easy to do, and for every white and dark mark, the Optical CAM and CRANK Sensor Simulator will also output a signal crest. Once you have the optical signature diagram done, scan it, and save in as an image file on your computer. You can also use a simple drawing software to draw the optical signature diagram.
Now you actually have everything you need, to develop your own crank sensor signal, that actually corresponds to that vehicle engine size. Next, we’ll show you how to apply the optical signature diagram to the actual engine, and make the engine start using the Optical CAM and CRANK Sensor Simulator. The idea here is to develop various optical signature diagrams over time, over many makes and models, and over many engine sizes, and truly make the Optical CAM and CRANK Sensor Simulator, a universal CAM and CRANK sensor signal simulator, that’ll render many, many years of service, even on future engines that haven’t even been developed yet. As said before, the optical signature diagrams, are universal in nature, and render the Optical CAM and CRANK Sensor Simulator the viable tool for years to come.
Using the Optical CAM and CRANK Sensor Simulator
We previous saw how the Optical CAM and CRANK Sensor Simulator circuit works, and how to develop the optical signature diagram. Now, let’s find out how to use the Optical CAM and CRANK Sensor Simulator, and the optical signature diagram in a real world application. But first, let’s learn how to change the optical signature diagram into a usable tool. Well, the answer is very simple.
From a known crank sensor waveform, as said before, we get the series if white and dark marks that determine the crank sensor signal or signature. Now here’s where it gets interesting. What you do is convert the long signal signature diagram, into a circular diagram, using the same signature. Use any photo editing software out there, and then use the polar coordinates effect or filter to make warp the linear image into a rounded warped image seen here.
It is that simple. Then, all you do is print the circular signature diagram, cut it into a round piece of paper, and stick or glue it to the crank sensor pulley. You can even use sticky paper to do the printing, just peal the back, and stick it to the crank pulley.
Ok, now you know how to apply the optical signature diagram to the engine. Now, let’s learn how to synchronize the crankshaft to the newly created optical signature diagram. And that, it’s also very simple.
All you do then, is set the engine at top dead center, mount the Optical CAM and CRANK Sensor Simulator to it’s holding bracket, and point the optical eye of the Optical CAM and CRANK Sensor Simulator to the long synch dark mark, which almost always signifies top dead center. You can stick the optical signature diagram in any position you want.
The important part is to then, set the engine at top dead center on compression, mount and point the simulator to the top dead center long mark. Now, your Optical CAM and CRANK Sensor Simulator is timed properly. You can do this operation in less than a minute. It’ll probably take you longer to set the engine in top dead center, than to time the Optical CAM and CRANK Sensor Simulator. Take either the sine wave or square waveform output, and connect it to the input of the vehicle’s crank sensor connector. At this point, you’re ready to start the engine. For every dark and white mark that the Optical CAM and CRANK Sensor Simulator sees, it’ll create a specific square wave signal, filtered by the LM555 microchip, and then fed into the small transformer for both, a sine and square wave output. The usefulness of the Optical CAM and CRANK Sensor Simulator, is in substitution, to diagnose intermittent problems, to check issues with the wiring, to diagnose the ECM, and many more issues whereby, you don’t know who’s at fault. Is it the ECM, the sensor, the wiring or some other software issue hidden in the maze of technical complexity. The Optical CAM and CRANK Sensor Simulator will be there for you, regardless of vehicle make, model, year or engine type for many years to come.
OBD-2 Data Link Connector Breakout Box
IMPORTANT NOTE. In this video, the Dataq DI-149 will be presented, which is separate from the OBD-2 DLC Breakout Box software.
Did it ever occurred to you that you can diagnose lots of problems through the OBD-2 DLC connector. Things like, chassis or sensor ground issues. And we’re not talking about a simple open ground circuit. We’re talking about ground resistance and intermittent issues. Well, we then present you with the OBD-2 DLC Breakout Box or Mr BOB DLC. This tool allows you to do all kinds of measurements on the DLC or OBD-2 data link connector pins. Yes, it’ll turn your PC, or Laptop into a virtual scope-like, measuring, and analysis machine. This gadget is a cutting edge tool, and it is the worlds best kept secret, when it comes to automotive data acquisition and component control. The OBD-2 DLC Breakout Box, is based on the Dataq DI-149 board. This is a 59 dollar unit, that supports all Microsoft Windows operating systems. By itself, the DI-149 board does nothing. We need to connect a few extra components and, yes, it’s a done deal. Also, we need the software that runs the OBD-2 DLC Breakout Box, which will be provided to you by Mandy Concepcion, the developer of the OBD-2 DLC Breakout Box. Yes, and it’ll be free of charge, so long as you build the gadget yourself.
The OBD-2 DLC Breakout Box with Dataq DI-149 circuit has the following. The OBD-2 DLC Breakout Box DI-149 is a product for general-purpose data acquisition applications, in a long line of low-cost starter kits from DATAQ. Suitable for measuring pre amplified analog signals, the DI-149 together with the included Mr BOB DLC software, allows real time data acquisition, playback, and analysis performance equal to, or better that other products that cost ten times more than its low price. This instrument has been sold to thousands of hobbyists and professionals, for countless data acquisition applications around the world. The DI-149 has noise canceling, differential analog inputs, and are protected to 150 volts, well suited for automotive applications. This is a tough and tolerant board, and used in conjunction with the OBD-2 DLC Breakout Box or Mr BOB DLC software and some extra components, it becomes a very capable tool. Here’s how the OBD-2 DLC Breakout Box circuit works. Later on we’ll show you how to use it, and how to build it.
The OBD-2 DLC Breakout Box is composed of the following. The Dataq DI-149, a few external resistors, diode, and a switch, and Mr BOB DLC software. That’s it, and then you put it together with the software, components and a PC or Laptop. This unit runs on a Microsoft Windows PC or Laptop, which today, almost everyone has. It doesn’t need much memory either. Any PC made within the last 12 years will work. The unit also has a double ended OBD-2 connector, that you can build yourself. So, you connect the OBD-2 DLC Breakout Box to the OBD-2 connector, and then if you want, also connect the scan tool right behind it. It is that simple. Afterwards, install and start the OBD-2 DLC Breakout Box or Mr BOB DLC software on your Laptop. Don’t forget, this is a full USB device. Here are the PC Board to OBD-2 DLC connector links. Pins 7 has two 10K resistor voltage dividers at the end. A switch is also part of the gadget, and one end of the switch also has a two 10K voltage dividers resistors. These are used to drop down the voltage and protect the gadget. Finally, the ground terminals are in series with a bias diode, done for protection in case of a accidental reverse connection to the battery. This gadget uses battery voltage and ground as reference to test all the OBD-2 pins. The software for the OBD-2 DLC Breakout Box works as follows.
The OBD-2 DLC Breakout Box program has 6 sections. The first is the starter alternator tests. Connecting the OBD-2 DLC Breakout Box, and starting the engine is enough for the unit to run various tests on the system. Many voltage drops tests are ran automatically, continuously, and very quickly. This section also turns your computer into a graphing multi-meter. Then, there’s a network test section. You see, the OBD-2 connector is the central point of testing for the entire car. This is a continuous graphing section, meant to detect network issues. Following, you also have the Voltmeter and Scope Graphing section, which turns the OBD-2 DLC Breakout Box into a very capable measurement unit. It’ll give you up to 8 channels of powerful measurements, which is more than what’s available on the market now. This is not a full fledged oscilloscope, but it is what you need to run tests on the OBD-2 connector. Any issues with a dead network will show up here, as well as power and ground issues. This is a fully visual section. On the DLC pinout section you get various images to help you during diagnostics. Then, on the power tests, you can run all kinds of automated power tests, while seeing a power graph at the same time. This is powerful and deterministic of any drivability issues. Finally, a dedicated ground unit testing section. It is estimated that at least 40% of vehicle issues is due to a ground problem. This is understandable, since the ground is connected throughout the car, at high resistance points in the chassis and engine block. With the ground testing section, you will know right away what’s wrong with your grounds, both chassis and sensor ground. The OBD-2 DLC Breakout Box is a very capable gadget, that turns your computer into a virtual OBD-2 breakout box. It doesn’t communicate with the car. It is not a scanner, but a measurement device with automated tests, meant to help you with Power, ground, network, and all other issues that can be detected at the OBD-2 DLC connector. Since the OBD-2 connector is a standard, this unit will certainly provide you with many years of service for the foreseeable future.
Using the OBD-2 DLC Breakout Box
The OBD-2 DLC Breakout Box, is a device or tool, that allows for all kinds of testing on the OBD-2 DLC connector. It is not a scan tool, and it doesn’t communicate with the vehicle ECM. It is only a measurement tool.
There are many scenarios to use the OBD-2 DLC Breakout Box, such as testing the communication signals, or listening to the network traffic, between the different modules in the car. Also, to test chassis and sensor ground issues using voltage drop measurements, which is built into the OBD-2 DLC Breakout Box, power tests that can determine if the alternator, or battery is at fault, starter tests that measure the drain on the battery as the starter engages, and even running compression tests, based on battery draw from the starter motor. Here are the scenarios where the OBD-2 DLC Breakout Box is useful. Scenario One. Looking at the inter-module network signals or between scanner and ECM. The car isn’t starting due to no spark, coil or injector pulse. This is important, because it’ll tell you right away two things. Imagine that the vehicle doesn’t start. There are many possibilities for this to happen. First, you need to know if the ECM is alive. How? Well, by initiating a network call to it using your cheap OBD-2 code reader.
So, first go to the start network connector or main splice and disconnect all the modules, except the ECM. You then connect the OBD-2 DLC Breakout Box and the cheap code reader right behind it. At this time, you can view all the incoming and outgoing signals between the scanner and the ECM. If the ECM is not responding, and it has good power feed and ground, you know the ECM is dead. But, more often than not, what happens is that another module or computer brings down the network. In cases like that, you then start to re-connect each module one at a time, at the star junction, while viewing the OBD-2 DLC Breakout Box. As soon as the shorted module is re-connected, the OBD-2 DLC Breakout Box laptop graphing voltmeter will show a signal drop. The OBD-2 DLC Breakout Box will save you the cost of buying an oscilloscope and pinching the OBD-2 connector wires, or damaging it in the process.
All the other scenarios for using this tool, are fully automated on the software. So, if you need to diagnose the power or grounds, it’s all done automatically. This is a nice tool to have if you want to tackle network, power and ground issues. The OBD-2 DLC Breakout Box usefulness, giving that the OBD-2 connector is standardized, will render many years of service to you.
About the Author
Mandy Concepcion has worked in the automotive field for over 21 years. He holds a Degree in Applied Electronics Engineering as well as an ASE Master & L1 certification. For the past 16 years he has been exclusively involved in the diagnosis of all the different electronic systems found in today’s vehicles. It is here where he draws extensive practical knowledge from his experience and hopes to convey it in his books. Mandy also produces an automotive technology DVD-Video series, writes auto repair books, develops automotive software and designs OBD-2 scanners, scopes and other diagnostic equipment.
