SERV1681_TXT technical presentation.pdf

Service Training Meeting Guide 681

SERV1681-01 January 2002

TECHNICAL PRESENTATION BASIC ENGINE BLOCK DIAGRAM

APPLICATION BLOCK DIAGRAM

P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19

DISCONNECT SWITCH

GROUND BOLT

J2

BATTERY

J1

8/12/16 INJECTORS P20/J20

SPEED/TIMING SENSOR

GROUND BOLT J3/P3 MACHINE INTERFACE CONNECTOR

J21/P21

J48/P48

UNFILTERED OIL PRESSURE SENSOR

J32/P32

J22/P22

FILTERED OIL PRESSURE SENSOR

J105/P105

J27/P27

FUEL FILTER DIFFERENTIAL PRESSURE SWITCH

J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

COOLANT TEMPERATURE SENSOR AFTERCOOLER TEMPERATURE SENSOR LOW OIL LEVEL SWITCH

LEFT TURBOCHARGER EXHAUST TEMPERATURE SENSOR RIGHT TURBOCHARGER EXHAUST TEMPERATURE SENSOR

J29/P29

P31/J31

J103/P103 J113/P113

24 V

15 AMP BREAKER

THROTTLE POSITION SENSOR

ATMOSPHERIC PRESSURE SENSOR LEFT TURBOCHARGER INLET PRESSURE SENSOR RIGHT TURBOCHARGER INLET PRESSURE SENSOR

WASTEGATE CONTROL SOLENOID

308-YL

THROTTLE BACK-UP SWITCH

KEY START SWITCH GROUND LEVEL SHUTDOWN SWITCH

+ BATTERY

CYLINDER RELAY

STARTING AID SWITCH

ENGINE ETHER START VALVE USER DEFINED SHUTDOWN

+ BATTERY TO PRELUBRICATION PUMP

TURBOCHARGER OUTLET PRESSURE SENSOR CRANKCASE PRESSURE SENSOR

113-OR J35/P35

P41/J41

ELECTRONIC SERVICE TOOL CONNECTOR TO VIMS, EPTC II OR MONITORING SYSTEM

ENGINE FAN CONTROL SOLENOID

P84/J84

A/C ON SWITCH

OIL RENEWAL CONTROL SOLENOID FAN SPEED SENSOR

3500 ENGINE CONTROLS ELECTRONIC UNIT INJECTION

3500B ENGINE CONTROLS ELECTRONIC UNIT INJECTION (EUI) MEETING GUIDE 681 SLIDES AND SCRIPT AUDIENCE Level II - Service personnel who understand the principles of engine systems operation, diagnostic equipment, and procedures for testing and adjusting.

CONTENT This presentation is designed to prepare a service technician to identify the components, explain their function, and service the 3500B Electronic Unit Injection (EUI) engines in current machine applications.

OBJECTIVES After learning the information in this presentation, the serviceman will be able to: 1. 2. 3. 4.

Locate and identify the major electrical/electronic components in the 3500 EUI system. Explain the functions of the major electrical/electronic components in the 3500 EUI system. Trace the flow of fuel and oil through the fuel system. Trace the flow of current through the engine electrical system.

PREREQUISITES Interactive Video Course "Fundamentals of Electrical Systems" (CD ROM) TEMV9002 Service Technician Workbench Tutorial (CD ROM included with STW software) NEHS0812 Caterpillar Machine Electronics Course (Five Modules) SEGV3001 - SEGV3005 Caterpillar 3500B MEUI Fuel System (CD ROM) RENR1395 Prior training in mechanical systems operation and testing and adjusting procedures for 3500B engines should be completed before participating in this training session. The participants should have PC skills and have completed training in the current Windows® operating system. Additionally, participants should have completed training in the most current Electronic Technician (ET) software.

Estimated Time: 8 Hours Visuals: 101 (2 X 2) Slides Serviceman Handouts: 6 Drawings/Data Sheets Form: SERV1681-01 Date: 1/2002 © 2002 Caterpillar Inc.

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REFERENCES Troubleshooting Guide "3500B Engines--Caterpillar Machines" Specifications "3500B Engines--Caterpillar Machines" Systems Operation, Testing and Adjusting "3500B Engines--Caterpillar Machines"

SENR1128 SENR1122 SENR1123

SUPPLEMENTARY TRAINING MATERIAL Brochure "Service Technician Workbench" Brochure "Caterpillar Electronic Technician"

NELG0028 NEDG6015

Service Technician Workbench Tutorial (Included with STW software) 3500 and 3500B Series of Diesel Engines Introduction to the 3500B Series Engine

NEHS0812 LERV1450 LEPV5149

EUI SERVICE TOOLS Software and Manuals Caterpillar Service Tool Software/Getting Started Guide - Service Technician Workbench NEHS0796 or Caterpillar Service Tool Software/Getting Started - Caterpillar Electronic Technician JEBD3003 Caterpillar Service Tool Software/Users Manual- Communication Adapter II NEHS0758 Mechanical Tools Engine Turning Tool Injector Height Setting Tool Group Base for 9U-5132 (specific to 3500B)

9S-9082 9U-5132 125-2744

Electronic Tools Laptop computer Communication Adapter II (Group) Cable, PC to Communication Adapter Cable, Communication Adapter to Machine Caterpillar Digital Multimeter Three Pin DT Breakout Harness Cable Probes Auxiliary ECM Power Supply Harness Timing Calibration Probe (Magnetic Pickup) Timing Calibration Probe Adapter Sleeve Timing Calibration Probe Cable

171-4400 96-0055 160-0133 146-4080 7X-6370 7X-1710 167-9225 6V-2197 7X-1171 7X-1695

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TABLE OF CONTENTS INTRODUCTION ..................................................................................................................5 Overview...........................................................................................................................6 EUI Fuel System Components..........................................................................................8 External Engine Views and Major Components .............................................................11 Electronic Timing Components ......................................................................................18 Machine Mounted Engine Components..........................................................................32 Other Systems Controlled by the ECM ..........................................................................34 ELECTRONIC CONTROL SYSTEM .................................................................................36 Fuel Injection ..................................................................................................................39 Fuel Injection Control System ........................................................................................41 FUEL SUPPLY SYSTEM ....................................................................................................57 Fuel Supply Circuit .........................................................................................................58 Fuel Supply Components................................................................................................60 SYSTEM POWER SUPPLIES.............................................................................................64 ECM Power Supply ........................................................................................................65 Speed/Timing Sensor Power Supply...............................................................................68 Injector Power Supplies ..................................................................................................69 Analog Sensor Power Supply .........................................................................................70 Digital Sensor Power Supply ..........................................................................................71 Wastegate Control Solenoid Power Supply ....................................................................72 ELECTRONIC SENSORS AND SYSTEMS ......................................................................74 Speed/Timing Sensing Circuit ........................................................................................76 Analog Sensors and Circuits...........................................................................................78 Engine Mounted Switches ..............................................................................................90 Digital Sensors and Circuits............................................................................................92 Engine Shutdown Systems..............................................................................................98 Ether Injection System..................................................................................................100 Demand Fan Controls ...................................................................................................101 CAT Data Link..............................................................................................................102 Pre-lubrication System..................................................................................................104 Logged Events ..............................................................................................................105 APPLICATION SPECIFIC SYSTEMS..............................................................................107 Oil Renewal System......................................................................................................108 Wastegate Control .........................................................................................................110 SLIDE LIST........................................................................................................................112 SERVICEMAN'S HANDOUTS .........................................................................................114

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3500B ENGINE CONTROLS

ELECTRONIC UNIT INJECTION (EUI)

2002 Caterpillar Inc. 1

INTRODUCTION This presentation discusses the 3500B Electronic Unit Injection (EUI) Engine Controls used in machine applications. The topics are sequenced as follows: • Major topics

- Introduction and Major Components - Electronic Control System - Fuel Supply System - System Power Supplies - Electronic Sensors and Systems - Application Specific Systems

INSTRUCTOR NOTE: This presentation requires competence in Electronic Technician (ET) programming and operations for 3500B engines.

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2

Overview The 3500B engines were direct replacements for the original 3500 Series engines. Many additional features and benefits have been incorporated into the 3500B Series which will be described later in the presentation. The 3500B engines equipped with Electronic Unit Injection (EUI) are available in construction equipment and industrial applications. Caterpillar machines currently powered by 3500 EUI engines include: • 3500 EUI applications

Off-highway Trucks

777 - 793

Wheel Loaders

992 - 994

Track-type Tractors

D11

Excavators

5130 - 5230

This list is generic and includes both the original 3500 Series engines and the 3500B engines. • System features

The 3500 EUI engines have many features and benefits not possible with mechanical fuel systems. These features include a very clean exhaust, improved fuel consumption and cold starting, simplified maintenance with fewer moving parts, and reduced operating costs.

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3

• Engine cross sectional view

This cross sectional view of the engine shows the injector installation and the pushrod arrangement in relation to the upper portion of the engine. This sectional view is similar to the original 3500 EUI engine. Major differences are the spring loaded injector push rods and the larger diameter camshaft (described later).

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3516B FUEL SUPPLY CIRCUIT (793C) FUEL PRESSURE REGULATOR CYLINDER HEAD

OIL RENEWAL INJECTOR ENGINE BLOCK

PRIMING PUMP SUPPLY

FUEL TANK

FUEL DIFFERENTIAL PRESSURE SWITCH PRIMARY FUEL FILTER

FUEL HEATER

FUEL TRANSFER PUMP

SECONDARY FUEL FILTERS (2 MICRON)

ECM

4 EUI Fuel System Components This schematic shows the various components in the 3500B EUI fuel delivery system. A detailed explanation of the system and the various components follows later in this presentation. The schematic above shows the 3516B fuel system as installed in the 793C Off-highway Truck. • Electronically similar to HEUI system • Injectors electronically signalled

The electronic components in the 3500B EUI fuel system are very similar to those used in other EUI and, to some extent, the HEUI electronic system. However, in this system, the injectors are actuated by camshafts. The injectors are electronically signalled, as in the original 3500 EUI system.

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BASIC ENGINE BLOCK DIAGRAM


P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19 J2


P20/J20


J48/P48


J32/P32

J22/P22


J105/P105

J27/P27

J106/P106

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

RIGHT TURBOCHARGER EXHAUST TEMPERATURE SENSOR

J28/P28

J29/P29

P31/J31

J103/P103 J113/P113

24 V

15 AMP BREAKER

J21/P21


LEFT TURBOCHARGER EXHAUST TEMPERATURE SENSOR

BATTERY

J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

DISCONNECT SWITCH

GROUND BOLT



113-OR J35/P35

308-YL


+ BATTERY


CYLINDER RELAY

STARTING AID SWITCH

ETHER START VALVE


USER DEFINED SHUTDOWN



ENGINE

P41/J41



P84/J84

A/C ON SWITCH


5 • Electrical block diagram

This electrical schematic shows the various components in the system and the section of the system in which they are located. On the left side of the schematic are the engine mounted components, and on the right side of the schematic are the machine mounted components. The connection between the two circuits is made by the Machine Interface Connector. Some components or circuits are not used by the fuel system, but are controlled by the engine ECM. For example: - Pre-lubrication Circuit - Exhaust Wastegate Control - Demand Fan Control - Ether Injection System

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6

• Six major component types:

This slide shows six major types of electrical/electronic components in the EUI fuel system:

- ECM

- ECM

- Throttle control

- Throttle Control

- Pressure sensor

- Pressure Sensor

- Temperature sensor

- Temperature Sensor

- Speed/timing sensor

- Speed/Timing Sensor

- Injector

- Injector The CAT Data Link (not shown) provides a two-way communication path between the EUI system and the other ECM’s or systems on the machine. The CAT Data Link also allows the ET service tool to communicate with the engine ECM. NOTE: Only one example of each sensor (pressure and temperature) is shown on the slide.

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7

External Engine Views and Major Components • Engine front view

The engine block is similar to the original 3500 block. The main difference is due to the larger camshaft which needs a larger bore in the block to accommodate the camshaft.

• ECM (arrow)

The principal component in the EUI system is the Electronic Control Module (ECM). The ECM (arrow) is mounted at the front of the engine.

• Additional components:

The following components are also located on the front of the engine:

- Timing calibration connector - Coolant flow sensor - Turbocharger outlet pressure sensor

- Timing Calibration Connector - Coolant Flow Sensor - Turbocharger Outlet Pressure Sensor

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1

2 3

8

• Engine rear view 1. Aftercooler temperature sensor 2. Machine interface connector 3. Speed/timing sensor

At the rear of the engine is the timing gear housing containing the following components: - Aftercooler Temperature Sensor (1) - Machine Interface Connector (2) - Speed/Timing Sensor (3)

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1

3

2

4 9

• Engine left side view 1. Coolant temperature sensor 2. Speed/timing sensor 3. Fuel filters 4. Oil filters

On the left side of the engine are the following components: - Coolant Temperature Sensor (1) on the thermostat housing - Speed/Timing Sensor (2) - Fuel filters (3) - Oil Filters (4) Additional components mounted on this side of the engine (to be explained later in the presentation) are: - Exhaust Temperature Sensor (one of two) - Filtered Oil Pressure Sender - Unfiltered Oil Pressure Sender

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1

2

5 4 3

10

• Engine right side view

On the right side of the engine are the following components:

1. Crankcase pressure sensor

- Crankcase Pressure Sensor (1)

2. Oil renewal injector

- Oil Renewal Injector (2)

3. Fuel transfer pump

- Fuel Transfer Pump (3)

4. Coolant flow switch

- Coolant Flow Switch (4)

5. Timing calibration connector

- Timing Calibration Connector (5)

Additional components on this side of the engine include: - Right Exhaust Temperature Sensor - Oil Level Switch - Wiring Harness

The wiring harness includes the Deutsch electrical connectors on the cylinder heads. The Deutsch connectors conduct current to the electronic unit injectors through internal wiring in the cylinder heads.

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11

The major component in the EUI system is the Electronic Control Module. • ECM--the "heart" of the system

• Personality module access panel located on rear of ECM

The ECM is the "heart" of the engine. The ECM performs engine governing, timing and fuel limiting. It also reads sensors and communicates to the instrument display system through the CAT Data Link. The Personality Module is located on the rear of the ECM through an access panel. The Personality Module is used to program the ECM with all the rating information for a particular application. The Personality Module can be changed by direct replacement or can be flash programmed (or reprogrammed) using a PC.

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12

• EUI wiring harness

The wiring harness provides two-way communication between the ECM and the engine sensors and connects the ECM to the unit injectors. The harness is routed from the ECM at the left front of the engine to the left side of the engine. The harness then crosses over to the right rear of the engine and is routed to the right side of the engine.

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13

• Coolant temperature sensor (arrow)

• Sensor functions

The engine Coolant Temperature Sensor (arrow) is located at the front of the engine on the thermostat housing. This sensor is used with the ECM to control various functions. The following systems or circuits use the Temperature Sensor output to the ECM: The Vital Information Management System (VIMS) or Caterpillar Monitoring System Coolant Temperature Gauge over the CAT Data Link. The High Coolant Temperature Warning Alert Indicator and Gauge on the VIMS or Caterpillar Monitoring System panel. (The information is transmitted over the CAT Data Link.) The Engine Demand Fan Control, if installed, uses the sensor signal reference to provide the appropriate fan speed. The Cat Electronic Technician (ET) status screen for coolant temperature indication. The Cold Mode engine control (i.e. elevated low idle and timing reference for cold mode operation). The Ether Aid control as a reference for Ether Aid operation.

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14

Electronic Timing Components • Speed/timing sensor (arrow)

This view shows the Speed/Timing Sensor (arrow). The sensor is mounted on the rear gear housing. This sensor is used to calculate engine speed and crankshaft position for timing purposes.

• Self-adjusting sensor

The sensor is self-adjusting, but special precautions are necessary during installation to prevent damage. (The precautions are described later in the presentation.)

NOTE: After installation, the sensor is initially in contact with the timing wheel.

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3

1

4

2

15

• Identify components: 1. Timing wheel 2. Speed/timing sensor 3. Dowel pin 4. 50/50 size slot and tooth

This view shows the Timing Wheel (1) and the Speed/Timing Sensor (2) on the engine. A dowel pin (3) on the camshaft and a corresponding hole on the timing wheel are used to time the wheel relative to the camshaft. The camshaft is then timed with the crankshaft at TDC. Notice the wide 50/50 size slot and equal size tooth (4) cut in the wheel. Three pairs of equal size slots and teeth are on the wheel. The other 21 slots and teeth are 80/20 relative size. These features are used to generate a digital signal necessary for timing. These functions are more fully explained later in the second section of this presentation. This timing wheel is common to all 3500 engines.

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16

• Timing wheel (arrow)

The timing wheel (arrow) is mounted on and driven by the left camshaft (not shown). The camshaft is driven by the rear gear train, as shown in this slide.

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17

• 3500B camshaft

Each cylinder has three corresponding camshaft lobes. The center lobe is is used to actuate the unit injector. The 3500B has a larger diameter camshaft to accommodate the higher injection pressures generated in the unit injector pumps. The cylinder block has a larger camshaft bore to accommodate the larger camshaft. (All 3500 engines are now being manufactured to this standard.)

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18

The injectors are actuated by the camshaft. This view also shows the valve train which is on both sides of the injector mechanism below the valve cover. • injector pushrod spring

Notice the 3500B injector pushrod spring, which maintains contact between the lifter roller and the camshaft lobe. This spring is designed to maintain cam follower and camshaft contact and protect the mechanism during a possible overspeed.

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19

• 3500B EUI injector

• 105 Volt signal determines start of injection

The 3500B EUI injector is actuated by the pushrod and rocker arm. Fuel flow is controlled by the ECM through a solenoid on the side of the injector. The injection cycle is initiated and terminated by the ECM with a 105 Volt signal. The start of injection and, therefore, timing are determined by the start of the signal. The duration of the signal from the ECM (and rpm) determines the quantity of fuel delivered per stroke. This operation is explained in more detail in the Electronic Controls section of the presentation.

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1 2

20

1. Fuel pressure regulator

2. Fuel lines to injectors

The Fuel Pressure Regulator (1) is located on the top right side of the engine. Fuel flows from the fuel filter base, through the steel fuel lines (2), to the EUI fuel injectors. Return fuel from the injectors flows through the fuel pressure regulator before returning to the fuel tank. Fuel pressure is controlled by the fuel pressure regulator.

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21

• Atmospheric pressure sensor (arrow)

The Atmospheric Pressure Sensor (arrow) is installed on the ECM mounting adapter and is vented to the atmosphere. This sensor has various functions which are fully described later in the presentation. Briefly, it performs the following functions: Ambient pressure measurement for automatic altitude compensation and automatic air filter compensation. Absolute pressure measurement for the fuel ratio control, ET, filter restriction, and Caterpillar Monitoring System panel (gauge) pressure calculations.

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1 2

22

The Turbocharger Inlet Pressure Sensor (1) is mounted between the air filter and the turbocharger. 1. Turbocharger inlet pressure sensor

This sensor is used in conjunction with the atmospheric pressure sensor to measure air filter restriction for engine protection purposes. The difference between the two pressure measurements is used as the filter differential pressure. The engine ECM uses this calculation to determine whether derating is necessary to protect the engine against the effects of excessive filter restriction. This function is referred to as Automatic Air Filter Compensation.

2. Ether cylinders

Depending on the application and air intake system configuration, either one or two Turbocharger Inlet Pressure Sensors may be used. If the machine is equipped with an ether start system, the ECM will automatically inject ether from the ether cylinders (2) during cranking. The operator can also inject ether manually with the ether switch in the cab. Ether will only be injected if the engine coolant temperature is below 10°C (50°F) and engine speed is below 1200 rpm.

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23

• Turbocharger outlet pressure sensor (arrow)

Also at the front of the engine in the vee is the Turbocharger Outlet (Boost) Pressure Sensor (arrow). This sensor is used with the ECM to control the air/fuel ratio electronically. This feature allows more accurate smoke control which was not possible with previous mechanically governed engines. The sensor reads boost pressure through a tube connecting the sensor to the manifold. The sensor also allows boost pressure to be read using the electronic service tools.

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24

• Exhaust temperature sensor (arrow)

One Exhaust Temperature Sensor (arrow) is mounted below each turbocharger. These sensors are used to warn of possible damaging conditions in the engine caused by excessive exhaust temperature. On the 793C, the sensors enable the ECM to derate the engine.

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25

• Filtered lubrication oil pressure sensor (arrow)

Mounted on the rear of the Oil Filter Group is the Filtered Lubrication Oil Pressure Sensor (arrow). This sensor is used to signal oil pressure to the ECM. The sensor is also used by the ECM to generate a low oil pressure warning for the operator. Mounted at the front of the Oil Filter Group (not shown) is the Unfiltered Lubrication Oil Pressure Sensor. This sensor is used by the ECM with the Filtered Lubrication Oil Pressure Sensor to calculate oil filter differential pressure. The oil filter differential pressure calculation provides a warning that the oil filters need to be changed. (This system is not designed to be a substitute for regular filter change maintenance requirements.)

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26

• Crankcase pressure sensor (arrow)

A Crankcase Pressure Sensor (arrow) may be mounted on the right side of the engine. This sensor is used to protect the engine by giving advance warning of a failure (i.e. a piston allowing excessive blowby which could soon cause considerable damage).

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• Timing calibration sensor (arrow)

The Timing Calibration Sensor (arrow) is installed when required for speed/timing sensor calibration in the flywheel housing. This sensor (magnetic pickup) is installed in the hole normally reserved for the timing pin. (The pin is used to position the crankshaft with the No. 1 piston at top dead center.)

NOTE: On some applications (i.e. track-type tractors) where accessibility is limited, this sensor is permanently installed.

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3 1

2

28

Machine Mounted Engine Components • Machine mounted components: 1. Brake pedal 2. Throttle pedal

Machine mounted components on off-highway trucks include: - Brake pedal (1) - Throttle pedal (2) - Throttle Position Sensor (3)

3. Throttle position sensor

The Throttle Position Sensor is attached to the throttle pedal. The Throttle Position Sensor provides the throttle position input to the ECM. • Elevated low idle

The ECM provides an elevated engine idle speed of 1300 rpm when the coolant temperature is below 60°C (140°F). Above 60°C (140°F), the elevated idle rpm is gradually reduced until the coolant temperature reaches 71°C (160°F). Above 71°C (160°F), the engine will idle at 700 rpm. Increasing the low idle speed helps prevent incomplete combustion and overcooling. To temporarily reduce the elevated idle speed, the operator can depress the throttle momentarily, and the idle speed will decrease to 700 rpm for 10 minutes.

• Throttle back-up switch

The Off-highway Truck Throttle Back-up Switch allows a "limp home" mode in the event of a throttle circuit failure.

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29

• Fuel filters

• Filter differential pressure switch

• Two micron fuel filter rating

Two fuel filters are installed on the left side of the engine. The priming pump is installed on the filter housing. A fuel filter differential pressure switch is installed on the front of the filter housing to provide a warning when the filters need replacement. It is important that the correct two micron fuel filters are used with this engine.

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OTHER SYSTEMS CONTROLLED BY THE ECM • Oil Renewal • Exhaust Wastegate Control • Engine Oil Prelube • Variable Speed Fan Control • Ether Injection System

30

Other Systems Controlled by the ECM Although not actually part of the fuel system, the following circuits are also controlled by the ECM. - Oil Renewal - Exhaust Wastegate Control - Engine Oil Prelube - Variable Speed Fan Control - Ether Injection System

These circuits are described later in the presentation.

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P26 T/C CONNECTOR

ECM



P20/J20


J48/P48


J32/P32

J22/P22


J105/P105

J27/P27

J106/P106

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23


J28/P28

J29/P29

P31/J31

J103/P103 J113/P113

24 V

15 AMP BREAKER

J21/P21



BATTERY

J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

DISCONNECT SWITCH

GROUND BOLT




308-YL


+ BATTERY


CYLINDER RELAY

STARTING AID SWITCH




113-OR J35/P35

P41/J41



P84/J84

A/C ON SWITCH


31 • Engine component identification

This schematic identifies the external EUI engine components for the 793C Truck. The components shown on the left side of the schematic are mounted on the engine and those on the right are machine mounted. Other machines may differ with the mix of sensors and other components. The appropriate Troubleshooting Guide must be used to verify the specific machine components.

INSTRUCTOR NOTE: At this time, it is recommended that each component be located on the engine and machine. The function of each can be reviewed with the students.

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ELECTRONIC CONTROL SYSTEM

32

ELECTRONIC CONTROL SYSTEM This section of the presentation explains the 3500B Electronic Control System including the following components:

- ECM - Personality Module - Electronic Unit Injector Solenoids - Timing Wheel Also covered are the following subsystems and related procedures:

- Timing control - Fuel quantity control - Speed control (governor) - Cold modes - Timing calibration

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• ECM: - Governor - Fuel system computer - Injection timing controller

The Electronic Control Module (ECM) functions as the governor and fuel system computer. The ECM receives all the signals from the sensors and energizes the injector solenoids to control timing and engine speed. The ECM is sealed except for access to the software which is contained in the Personality Module (next slide). This ECM is the second generation of Advanced Diesel Engine Management Systems and is often referred to as "ADEM II."

• Same ECM used in all 3500B applications

This ECM is used on all 3500B engines, including machine and industrial applications.

• 3500B EUI ECM not interchangeable with 3400E HEUI ECM

This ECM physically looks the same as the 3400 HEUI ECM. However, it is very different electrically in that the wave form (described later in the presentation) for the injectors has a different shape. Additionally, this ECM has no pump control valve output.

NOTE: The ECM has an excellent record of reliability. Therefore, any problems in the system are most likely to be in the connectors and wiring harness. In other words, the ECM should typically be the last item in troubleshooting.

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• Personality module contains software

The Personality Module (shown here removed from the ECM) contains the software with all the fuel setting information (such as horsepower, torque rise and air/fuel ratio rates) which determines how the engine will perform. The Personality Module is installed on the lower face of the ECM, behind the access panel. At this time, two methods can be used to update the software: 1. Remove and replace the Personality Module. 2. Flash Programming: Electronic reprogramming of the Personality Module.

• ECM is sealed except for personality module

NOTE: The ECM is sealed and needs no routine adjustment or maintenance. The Personality Module is mounted within the ECM. Installation of the Personality Module is the only reason to enter the ECM. This operation would normally be performed during an ECM installation or a software update.

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Fuel Injection • Unit injectors • Electrically signalled, mechanically actuated

The 3500B EUI injector is very similar to the original 3500 EUI injector. The injector is controlled electrically by the ECM. The signal from the ECM controls the opening and closing of the solenoid valve. The solenoid valve controls the flow of high pressure fuel to the cylinder. This system enables the ECM to control fuel volume and timing.

• Injector codes

The 3500B injector now has bar and numerical codes marked on the tappet. The numerical code must be entered into the ECM using ET. The purpose of this code is to ensure that all injectors are matched as perfectly as possible in performance, both in timing and fuel quantity.

• Programming injector codes

If an injector is replaced, moved to another position on the engine, or if two injectors are switched, then the injector codes must be reprogrammed. The injector codes are programmed into the ECM using ET and the Calibrate Sensor Screen. Failure to enter the codes into a new ECM may result in unequal timing and fuel delivery between cylinders. WARNING The injector solenoids operate on 105 Volts direct current. Always remain clear of the injector area when the engine is running or electrical shock may occur.

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EUI INJECTOR TESTING METHODS • INJECTOR SOLENOID TEST • CYLINDER CUT-OUT • AUTOMATIC INJECTOR TEST

36 • Injector testing

These tests can be used to determine which cylinder or injector is malfunctioning: INJECTOR SOLENOID TEST This test is performed while the engine is stopped. The injector solenoids can be tested automatically with ET using the Injector Solenoid Test. This function individually tests each solenoid in sequence and indicates if a short or an open circuit is present. CYLINDER CUT-OUT (Manual test) This test is performed while the engine is running at any speed. The 105 Volt pulses can be individually cut out to aid in troubleshooting misfire problems in the injector and the cylinder. AUTOMATIC CYLINDER CUT-OUT This test is performed with ET while the engine is running at any speed. The test makes a comparative evaluation of all injectors and numerically shows the results. The test enables an on-engine evaluation of the injectors. A satisfactory test of all injector solenoids without any diagnostic messages means that a problem is likely mechanical and in the cylinder. (AUTOMATIC) MULTIPLE CYLINDER CUT-OUT This test is performed with current engines and enables multiple cylinders to be cut-out simultaneously.

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EUI CONTROL LOGIC TIMING CONTROL ENGINE SPEED FUEL QUANTITY COOLANT TEMPERATURE

DEGREES BTDC

TIMING FUEL RPM

SELECT TIMING

DESIRED TIMING BTDC

CONVERT DESIRED TIMING

FUEL INJECTION TIMING WAVE FORM

COLD MODE

37 Fuel Injection Control System • Fuel timing control

This diagram shows the timing control logic within the ECM.

• Inputs to timing control

Engine speed and fuel quantity (which relates to load) inputs are received by the timing control. These combined inputs determine the start of fuel injection.

• Benefits of a "smart" timing control

The timing control provides the optimum timing for all conditions. The benefits of a "smart" timing control are: - Reduced particulates and lower emissions - Improved fuel consumption while still maintaining performance - Extended engine life - Improved cold starting

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3500B ELECTRONIC GOVERNOR

COOLANT TEMPERATURE SENSOR

SHUTDOWNS

ECM 8 7 SIGNALS 6 TO FUEL 5 INJECTORS 4 3 2 1

ELECTRONIC GOVERNOR FUEL INJECTION CONTROL

SPEED/TIMING SIGNAL

ENGINE RPM

FRC MAPS

TORQUE MAPS

ENGINE CONTROL LOGIC

THROTTLE

TDC ENGINE RPM

ENGINE RPM TURBO OUTLET AND ATMOSPHERIC PRESSURE SENSORS

TIMING WHEEL SPEED/TIMING SENSOR

38 • Fuel quantity control • Inputs to fuel quantity control

Three inputs control fuel quantity: 1. Engine speed 2. Throttle position 3. Boost These signals are received by the electronic governor portion of the ECM. The governor then sends the desired fuel signal to the fuel injection control. The electronic governor also receives signals from the fuel ratio control and torque control.

• Start of injection determines timing • Injection duration determines fuel quantity

Two variables determine fuel quantity and timing: - The start of injection determines engine timing. - The injection duration determines the quantity of fuel to be injected.

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BASIC ENGINE BLOCK DIAGRAM ECM P26 T/C CONNECTOR


J2 J1

8/12/16 INJECTORS

GROUND BOLT

P20/J20

J3/P3

J21/P21

J48/P48

J32/P32

J29/P29

J105/P105

J27/P27

J106/P106

J23/P23

SPEED/TIMING SENSOR


AFTERCOOLER TEMPERATURE SENSOR

LOW OIL LEVEL SWITCH FUEL FILTER DIFFERENTIAL PRESSURE SWITCH

MACHINE INTERFACE CONNECTOR UNFILTERED OIL PRESSURE SENSOR

CRANKCASE PRESSURE SENSOR

ATMOSPHERIC PRESSURE SENSOR

TURBOCHARGER OUTLET PRESSURE SENSOR J47/P47

J22/P22

P30/J30

J28/P28

LEFT TURBOCHARGER INLET PRESSURE SENSOR

P31/J31

J25/P25

RIGHT TURBOCHARGER INLET PRESSURE SENSOR

COOLANT FLOW SWITCH




39 • Speed/timing sensor

The Speed/Timing Sensor serves three basic functions in the system: 1. Engine speed measurement

• Three functions of speed/timing sensor

2. Engine timing measurement 3. Cylinder identification and TDC location The Speed/Timing Sensor is mounted on the rear housing below the timing wheel. This sensor is self-adjusting during installation and has zero clearance with the timing wheel.

• Sensor installation

The sensor head is extended prior to installation. The action of screwing in the sensor pushes the sensor head back into the body when the head contacts the timing wheel. This contact is momentary while the engine is starting. After initial start-up, the head runs with zero clearance.

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SPEED/TIMING SENSOR P2 J2

SPEED/TIMING SENSOR

ECM P20 J20 OR BK WH

TIMING CALIBRATION CONNECTOR

996-GN 998-BR 999-WH F723-PK F724-PU

A B C

P26 1 2

32 29 38 18 12

+V TIMING DIGITAL RETURN PRIMARY ENGINE SPEED TIMING CAL + TIMING CAL -

P1 J1

40 • Speed/timing sensor

The Speed/Timing Sensor (left rear of engine) measures engine speed for governing and crankshaft position for timing purposes and cylinder identification.

• Power supply

The ECM supplies 12.5 ± 1 Volts to the Speed/Timing Sensor. Connector pins A and B transmit the common power supply to the sensor. The C connector pin transmits the signals from the sensor to the ECM.

NOTE: The Speed/Timing Sensor has a dedicated power supply. No other circuits should be spliced into this power supply.

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41

• Timing wheel and speed/timing sensor

The Timing Wheel is indexed with a drilled hole which is mated to a dowel on the camshaft. This dowel locates the wheel in the correct position on the camshaft relative to the crankshaft. As previously stated, the Timing Wheel has a total of 24 teeth. 21 teeth are large with small spaces between them (80/20 relative size). The other three teeth and spaces have equal dimensions (50/50 relative size). This configuration is used by the ECM as a reference point for determining the position of the engine for fuel timing. The Speed/Timing Sensor can identify the equal size teeth because they create a different signal pattern than the other teeth.

NOTICE The head of the sensor MUST NOT be positioned in the wide timing wheel slots during installation. Incorrect positioning will cause damage to the sensor head.

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CYL. NO. 3 TDC

REF

REF SPEED/TIMING SENSOR CYL. NO. 4 TDC REF TIMING CALIBRATION RANGE ± 7° 50/50 TOOTH SLOT

CYL. NO. 8 TDC

80/20 TOOTH SLOT

50/50 TOOTH SLOT

50/50 TOOTH SLOT

42 The Speed/Timing Sensor is positioned over the circumference of the teeth. • Sensor generates a PWM signal from timing wheel teeth

The teeth and sensor generate a Pulse Width Modulated (PWM) signal for the purpose of timing and a frequency modulated output for speed measurement.

INSTRUCTOR NOTE: A description of PWM signals is provided later in this presentation.

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TIMING GEAR TOOTH TABLE TABLE PWM DUTY CYLINDER CYCLE ENTRY REFERENCE A B C D E F G H 80/20 %

A

80 % 50 % 80 % 80 % 80 % 50 % 50 % 80 % 50/50%

B

CRANKING

NONE IDENTIFIED

80/20 %

C

80/20 %

80/20 %

E

D

50/50%

F

50/50%

G

H

TIMING WHEEL ROTATION

43 • Cranking • Timing wheel teeth and spacing

The Speed/Timing Sensor uses the timing wheel with the teeth arranged as shown to initially determine: - Top Dead Center No. 1 (When found, the cylinders can be identified.) - Engine speed The sequence of signals shown in the second column (PWM duty cycle) is analyzed by the ECM. At this point, no fuel will be injected until certain conditions have been met.

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TIMING GEAR TOOTH TABLE TABLE PWM DUTY CYCLE ENTRY 80 % A 50 % B 80 % C 80 % D 80 % E 50 % F 50 % G 80 % H

CYLINDER REFERENCE

AFTER PATTERN RECOGNITION

NO CYL. NO. 1 NO NO CYL. NO. 2 NO NO CYL. NO. 7 TIMING WHEEL ROTATION

A

B

C

CYL. NO. 1 REFERENCE EDGE

E

D

CYL NO. 1 TDC

F

CYL. NO. 2 REFERENCE EDGE

G

H

CYL. NO. 2 TDC

44 • After pattern recognition

• Initial firing sequence

During start-up, the sensor initially monitors the pulses created by the passing teeth and identifies the sequence as shown. After a complete rotation, the control can recognize the location of TDC from the pattern in the above illustration. During initial cranking, no fuel is injected until: - The Timing wheel has completed a revolution (the sensor has read the three 50/50 teeth). - TDC for all cylinders is identified by the control. After the sensor has provided the necessary signals, the ECM is ready to start injection. NOTE: The reference points in the illustration are positions on the timing wheel from which the control measures the point of injection and TDC.

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TIMING GEAR TOOTH TABLE TABLE PWM DUTY CYLINDER ENTRY CYCLE REFERENCE 80 % NO A 50 % CYL. NO. 1 B 80 % NO C 80 % NO D 80 % CYL. NO. 2 E 50 % NO F 50 % NO G 80 % CYL. NO. 7 H

NORMAL OPERATION

TIMING WHEEL ROTATION

A

B

C

F

E

D

ASSUMED TDC

DES TIMING

CYL. NO. 1 REFERENCE

H

60° BTDC (EEPROM)

60° BTDC (EEPROM)

DELAY

G

ASSUMED TDC

DES TIMING

NO. 1 INJECTION

NO. 2 INJECTION

CYL. NO. 1 ACTUAL TDC (CALIBRATED)

CYL. NO. 2 REFERENCE

CYL. NO. 2 ACTUAL TDC (CALIBRATED)

45 • Normal operation

• Signal pattern identifies TDC • Conditions for injection

During normal operation, the ECM can determine timing (assumed TDC) from the cylinder reference point for each cylinder. The actual TDC is stored by the ECM after calibration is performed. Injection timing is calibrated by connecting a TDC probe to the service access connector on the engine harness, and by activating the calibration sequence with the Caterpillar ET service tool. The ECM raises the engine speed to 800 rpm (to optimize measurement accuracy), compares the actual No. 1 TDC location to the assumed cylinder No. 1 TDC location, and saves the offset in the EEPROM (Electrically Erasable Programmable Read Only Memory).

NOTE: The calibration offset range is limited to ± 7 crankshaft degrees. If the range is exceeded, the offset is set to zero (no calibration) and a calibration diagnostic message is generated.

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TIMING CALIBRATION SENSOR P2 J2 ECM

SPEED/TIMING SENSOR

P20 J20 OR BK WH

TIMING CALIBRATION SENSOR

996-GN 998-BR 999-WH F723-PK F724-PU

A B C

32 29 38 18 12

+V TIMING DIGITAL RETURN PRIMARY ENGINE SPEED TIMING CAL + TIMING CAL -

P1 J1 P26 1 2

TIMING CALIBRATION CONNECTOR

46 • Timing calibration sensor

The Timing Calibration Sensor (magnetic pickup) is installed in the flywheel housing during calibration. The connector is located above the ECM. (On some machines, i.e. D11 Tractor, the sensor is permanently installed.) Using the Caterpillar ET service tool, timing calibration is accomplished automatically for both sensors when selected on the appropriate screen. The desired engine speed is set to 800 rpm. This rpm setting is performed to avoid instability and ensure that no backlash is present in the timing gears during the calibration process. Also, the system has a repeatable point for improved calibration accuracy.

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TIMING CALIBRATION TIMING WHEEL

REFERENCE EDGE TO TDC DISTANCE REFERENCE EDGE

ASSUMED CYL. NO. 1 TDC

-7°

+7° ±7°

TIMING CALIBRATION SENSOR SIGNAL

ACTUAL CYL. NO. 1 TDC

TIMING REFERENCE OFFSET

MAXIMUM TIMING REFERENCE OFFSET ± 7 DEGREES

47 • Timing calibration • Corrects small crankshaft to timing gear tolerances • Calibration offset range ± 7 degrees

As the Speed/Timing Sensor uses the timing wheel for a timing reference, timing calibration improves fuel injection accuracy by correcting for any slight tolerances between the crankshaft, timing gears and timing wheel. During calibration, the offset is saved in the ECM EEPROM (Electrically Erasable Programmable Read Only Memory). The calibration offset range is limited to ± 7 crankshaft degrees. If the timing is out of range, calibration is aborted. The previous value will be retained and a diagnostic message will be logged. The timing must be calibrated after performing the following procedures: 1. ECM replacement 2. Speed/timing sensor replacement 3. Timing wheel replacement 4. Camshaft, crankshaft or gear train replacement

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INJECTION CURRENT WAVEFORM ONE CYCLE

CURRENT FLOW

PULL-IN PEAK CURRENT

HOLD-IN PEAK CURRENT

0

1

2

3

4

5

TIME (MILLISECONDS)

48

• Unit injector current flow

This illustration shows how the current increases initially to pull in the injection coil and close the poppet valve. Then, by rapidly chopping (pulsing) the 105 Volts on and off, current flow is maintained. The end of injection occurs when the current supply is cut off and fuel pressure drops rapidly in the injector.

INSTRUCTOR NOTE: This waveform may be demonstrated with a 9U7330 Digital Multimeter (or equivalent) and a current probe.

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FUEL SYSTEM COLD MODES • • • • •

Speed Control Fuel Limiting Injection Timing Injector Cold Mode Cutout Ether Injection

49

• Cold modes

The EUI fuel system is designed to modify its operational characteristics during cold conditions. This modification is done to protect the environment and to improve the operational characteristics of the engine.

• Cold mode cylinder cutout

A feature which was introduced with the 3500B is the Cold Mode Cutout. This feature activates when the engine is at low speed, load and temperature. As each individual cylinder is cut out, the ECM looks at the fuel rate measurement. If the fuel rate does not increase, the ECM assumes that this cylinder is not firing. To protect the dead cylinder from the effects of fuel washing down the piston and liner, the ECM leaves the cylinder in the cutout condition. The ECM now goes to the No. 2 cylinder and repeats the process. After the last cylinder is checked, the ECM goes to cylinder No. 1 and starts again. The engine may appear to misfire during the process, but this condition is normal. Checking the active faults with the engine running will verify that no electrical faults are present. This function is turned off when the throttle is opened more than 25%, coolant temperature is above 60°C or if the engine speed is above 1300 rpm. INSTRUCTOR NOTE: The various cold modes are tabulated in Serviceman's Handout No. 4.

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FUEL SYSTEM LIMITS • Maximum Horsepower • Maximum Torque • Fuel Ratio • Cold Mode Limit • Cranking Fuel Limit

50

• Fuel system limits

Just as earlier engines had mechanical limits to determine maximum fuel delivery during full load, full torque and acceleration, the EUI system has electronic limits to protect the engine. These limits are: - Maximum Horsepower - Torque Limit (Determines torque rise characteristics) - Fuel Ratio Control (Limits fuel until sufficient boost is available) - Cold Mode Limit (Limits fuel with cold engine to control white smoke) - Cranking Fuel Limit (Limits fuel during cranking) An acceleration delay during start-up holds the engine at low idle for two seconds or until the oil pressure reaches 140 kPa (20 psi).

• Variable horsepower

Off-highway Trucks have a system which increases engine horsepower in direct drive only. This system protects the drive line from excessive torque in the lower gears. The feature can be overridden with ET when dynamometer testing.

• Economy shift mode

Off-highway Trucks also have a service tool programmable feature which is designed to lower shift points and the fuel limit to improve fuel consumption at the customer's request.

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FUEL SYSTEM DERATES • Automatic Altitude Compensation • Automatic Filter Compensation • Engine Warning Derate • High and Low Boost Derate

51

• Fuel system derates

As the system limits fuel for every condition, derates are also built into the system for protection. These derates are individually covered later in the presentation, but are summarized here: - Automatic Altitude Compensation (Altitude derate) - Automatic Filter Compensation (Derates for air filter restriction if installed) - Engine Warning Derate for the following conditions: Low oil pressure High coolant temperature High exhaust temperature High and low boost If a loss of boost sensor output occurs, the ECM assumes zero boost pressure. Although not strictly a derate, power is reduced by approximately 50 to 60%.

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INSTRUCTOR NOTE: This material will be reinforced if the following ET tasks are demonstrated. Review the material with questions following the tasks. The demonstration can be performed on an engine or machine with a laptop computer. The suggested topics are: Basic ET review (if required) Status screens with all appropriate parameters Active diagnostic codes Logged diagnostic codes Events screen and overspeed histogram Configuration screen Timing calibration Injector solenoid test Cylinder cutout test Automatic injector test Program injector codes Air fuel ratio control setting (read and change)

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FUEL SUPPLY SYSTEM

52

FUEL SUPPLY SYSTEM This portion of the presentation describes the operation of the EUI Fuel Supply System as used on the 3500B engines in machine applications.

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3516B FUEL SUPPLY CIRCUIT (793C) FUEL PRESSURE REGULATOR CYLINDER HEAD

OIL RENEWAL INJECTOR ENGINE BLOCK

PRIMING PUMP SUPPLY

FUEL TANK

FUEL DIFFERENTIAL PRESSURE SWITCH PRIMARY FUEL FILTER

FUEL HEATER

FUEL TRANSFER PUMP


ECM

53 • Fuel supply circuit

Fuel Supply Circuit The system illustrated is for a 3516B in the 793C truck. Other systems may vary according to the application. Fuel is drawn from the tank through a fuel heater (if equipped) and through the primary fuel filter to the fuel transfer pump. Fuel from the transfer pump flows through the ECM for cooling purposes. From the ECM, the fuel flows through the secondary fuel filters. Fuel from the fuel filter base flows to the fuel injectors in the cylinder heads. Return fuel from the injectors flows through the fuel pressure regulator and the fuel heater before returning to the fuel tank. The fuel heater utilizes the hot return fuel from the engine to heat the incoming fuel passing through the filters. The heater prevents plugging of the filters in extremely cold conditions.

➥

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The Oil Renewal System is controlled by the engine ECM. A small amount of engine oil flows from the engine block to the oil renewal injector manifold. The oil flows from the oil renewal injector manifold into the return side of the fuel pressure regulator. The engine oil mixes with the fuel in the return line. It then flows to the tank. The combined oil and fuel mixture circulates back to the injectors to be burned with the fuel. It should be noted, however, that the ratio of oil to fuel is quite low. This circuit is more fully described later under Application Specific Systems.

NOTICE • Two micron secondary filters

All current 3500 engines are equipped with two micron secondary filters. This requirement is common with most high pressure fuel systems. Failure to meet the two micron filter requirement will result in less than expected life for the injectors.

INSTRUCTOR NOTE: Refer to Serviceman's Handout No. 6 when discussing the two micron filter requirement.

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1 2

54

• Fuel system components: 1. Transfer pump 2. Bypass valve

Fuel Supply Components The fuel transfer pump (1) is driven by the front gear train. The fuel transfer pump contains a bypass valve (2) to protect the fuel system components from excessive pressure. The bypass valve setting is higher than the setting of the fuel pressure regulator (next slide). Fuel flows from the transfer pump through the ECM and the secondary fuel filters located on the left side of the engine.

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2

1

55

• Fuel system components: 1. Steel tubes 2. Fuel pressure regulator

Fuel flows from the fuel filter base through the steel tubes (1) to the fuel injectors. Return fuel from the injectors flows through the Fuel Pressure Regulator (2) before returning to the fuel tank. Fuel system pressure is controlled by the Fuel Pressure Regulator. This valve is set at 415 to 450 kPa (60 to 65 psi). The valve is positioned downstream of the fluid manifold fuel passages and the injectors. Fuel which passes through the valve is returned to the fuel tank. The fuel lines from both fuel passages in the manifolds are joined at the regulating valve.

• Fuel pressure test point

Fuel pressure can be checked at the Fuel Pressure Regulator Valve by removing a plug and connecting a gauge.

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CYLINDER HEADS MUI AND EUI MUI

EUI

56 • MUI and EUI installation differences

This slide shows the difference between the Mechanical Unit Injection (MUI) and current Electronic Unit Injection (EUI) installation in the cylinder head. Notice the Helper Spring on the injector pushrod. This arrangement is designed to keep the follower in constant contact with the camshaft. The helper spring is required due to the increased injection pressures of 151 MPa (22,000 psi) and the steeper, high lift camshaft lobe profile.

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ELECTRONIC UNIT INJECTOR

SECONDARY FILTER

FUEL PRESSURE REGULATOR

ECM TRANSFER PUMP

FUEL TANK PRIMARY FILTER

FUEL TANK

57 • Unit injector fuel supply

This view shows the injector and its fuel supply circuit. A larger volume of fuel passes through the injector than is required for injection. This extra flow is used to cool the injector, which is also surrounded by coolant. INSTRUCTOR NOTE: To reinforce this presentation, the following tasks may be demonstrated on an engine using the Service Manual procedures: Remove and install a unit injector. Perform the necessary timing adjustments. Prime the fuel system. Using the ET, perform an Injector Solenoid Test and Cylinder Cutout Test. Check for active and logged faults.

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3500B SYSTEM POWER SUPPLIES • ECM: 24 VOLTS • SPEED/TIMING SENSORS: 12.5 VOLTS • INJECTORS: 105 VOLTS • ANALOG SENSORS: 5 VOLTS • DIGITAL SENSORS: 8 VOLTS • WASTEGATE CONTROL SOLENOID: 0 - 24 VOLTS

58

SYSTEM POWER SUPPLIES • Six system power supplies

The 3500B EUI system has one external and five internal power supplies with various voltages as shown. EXTERNAL POWER SUPPLIES ECM power supply

24 Volts

INTERNAL POWER SUPPLIES Speed/Timing Sensor power supply

12.5 Volts

Injector power supply

105 Volts

Analog Sensor power supply

5 Volts

Digital Sensor power supply

8 Volts

Wastegate Control Solenoid power supply 0 - 24 Volts

The power supplies are described in detail in the following section.

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ECM POWER SUPPLY BLOCK DIAGRAM


BASIC ENGINE BLOCK DIAGRAM P26 T/C CONNECTOR

ECM


GROUND BOLT (FRAME)

DISCONNECT SWITCH

BATTERY

J1 GROUND BOLT (ENGINE)

8/12/16 INJECTORS

15 AMP BREAKER

J3/P3 MACHINE INTERFACE CONNECTOR

24 V

113-OR KEY START SWITCH

59 ECM Power Supply • 24 Volt power supply

• Power supply components

The power supply to the ECM and the system is drawn from the 24-Volt machine battery. The principle components in this circuit are: - Battery - Key Start Switch - Main Power Relay - 15 Amp Breaker - Ground Bolt - ECM Connector (P1/JI) - Machine Interface Connector (J3/P3) If the supply voltage exceeds 32.5 Volts or is less than 9.0 Volts, a diagnostic code is logged. (See the Troubleshooting Guide for complete details on voltage event logging.) NOTE: The Ground Bolt and the Machine Interface Connector are the only power supply components mounted on the engine.

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ECM POWER SUPPLY CIRCUIT ENGINE BATTERY AND CHARGING SYSTEM

ENGINE BLOCK GROUND BOLT

(-) 24 VOLTS DC (+)

BREAKER 15 A

10 AMP

MACHINE INTERFACE P1 J1 CONNECTOR 05 229-BK-14 11 229-BK-14 04 150-RD-14 1 150-RD-14 06 2 113-OR 23 26 113-OR P3 J3

ECM

(-) BATTERY (+) BATTERY KEY SWITCH ON

112-PU 308-YL 117-RD

200-BK

105-RD

R C OFF S B ST KEY START SWITCH

60 • ECM power supply circuit

This schematic shows the principle components for a typical 3500B ECM power supply circuit. Battery voltage is normally connected to the ECM. However, an input from the key start switch turns on the ECM. Battery voltage may be checked using the service tool status screen. The machine wiring harness can be bypassed for troubleshooting purposes. These steps are described in the Troubleshooting Procedure. Notice the P1/JI and P3/J3 connectors in the circuit (described on the next slide.)

INSTRUCTOR NOTE: The power supply cables are paired between the battery and the ECM to reduce resistance. Not all connectors are shown between the machine interface connector and the 15 amp breaker. Refer to the machine electrical schematic for complete details.

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ECM CONNECTORS 40 PINS, WIRE SIDE P2 1

2

3

P1 4

5

6

1

2

3

4

5

6

7

12

7

12

13

18

13

18

19

22

19

22

23

28

23

28

29

34

29

34

35

36

37

38

39

40

35

36

37

38

39

40

61 A common but vital part of all the power supplies (and sensor circuits) described to this point is the 40 pin connector. • J1/J2 40 pin connectors

This slide shows the two ECM 40 pin connectors, P1 and P2, looking from the wire side. The pins highlighted in the P1 connector are for the ECM power supply circuit.

• J3/P3 40 pin connector

The system also includes the J3/P3, 40 pin Machine Interface Connector. This 40 pin connector transmits the power supply from the machine wiring to the engine wiring harnesses. The Troubleshooting Guide identifies the relevant pins for each circuit in this manner. The J3/P3 connector is identified identically and is also a part of the system power supply.

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SPEED/TIMING SENSOR POWER SUPPLY 12.5 ± 1 VOLTS P2 J2 ECM SPEED/TIMING SENSOR

P20 J20 OR BK WH

996-GN 998-BR 999-WH

A B C

32 29 38 18 12

+V TIMING DIGITAL RETURN ENGINE SPEED TIMING CAL + TIMING CAL -

P1 J1

62 Speed/Timing Sensor Power Supply • 12.5 Volt power supply from ECM

The Speed/Timing Sensor has a dedicated power supply. The ECM supplies 12.5 ± 1 Volts to the Speed/Timing Sensor. Connectors A and B send the common power supply to the sensor. The C wire transmits a separate signal to the ECM. This power supply is not battery voltage, but is generated and regulated within 1.0 Volt by the ECM. This power supply and the Speed/Timing Sensor are vital parts of the EUI system. A failure of the sensor will result in an engine shutdown.

NOTICE Connecting another system or accessory to the Speed/Timing Sensor power supply will cause an engine malfunction or failure.

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3512B INJECTOR WIRING SCHEMATIC INJECTOR SOLENOIDS SOL 1 SOL 3

J52/P52 1 2 3 4

P2 J2

ECM

A701-GY F726-YL A703-BR F726-YL

16 05 32

SOLENOID 1 POWER SOLENOID 1/3 RETURN SOLENOID 3 POWER

A702-PU F727-BU A704-GN F727-BU

40 11 34


A705-BU F728-BR A707-PU F728-BR

32 17 38


A706-GY F729-GN A708-BR F729-GN

28 21 22


A709-OR F730-GY A711-PU F730-GY

37 27 31


A710-GY F731-OR A712-BR F731-OR

18 33 12


J56/P56 SOL 2 SOL 4

1 2 3 4 J53/P53

SOL 5 SOL 7

1 2 3 4 J57/P57

SOL 6 SOL 8

1 2 3 4 J54/P54

SOL 9 SOL 11

1 2 3 4 J58/P58

SOL 10 SOL 12

1 2 3 4

63 Injector Power Supplies • 105 Volt power supply

The injectors are supplied with power from the ECM at 105 Volts. For this reason, precautions must be observed when performing maintenance around the valve covers. On the 3512B and 3516B, two of the internal power supplies are used for the injectors. If a failure occurs, only one bank of injectors could have failed. On the 3508B, only one of the internal power supplies is used. As previously mentioned, the same ECM is used on all three configurations. If an open or a short occurs in the injector circuit, the ECM will disable that injector. The ECM will periodically try to actuate that injector to determine if the fault is still present and will disconnect or reconnect the injector as appropriate.

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ENGINE COOLANT TEMPERATURE SENSOR

+V ANALOG ANALOG RETURN SIGNAL



TURBO OUTLET PRESSURE SENSOR


RIGHT TURBO INLET PRESSURE SENSOR




LEFT TURBO INLET PRESSURE SENSOR




J21 P21

P1 J1

ECM

A B C

36 30

+V ANALOG SUPPLY ANALOG RETURN

P22 J22 A B C P23 J23 A B C

3500B ANALOG SENSOR POWER SUPPLY

P25 J25 A B C

5 ± 0.5 VOLTS

P27 J27 A B C P28 J28 A B C P43 J43 A B C P48 J48



A B C

64 Analog Sensor Power Supply • Provides power to all analog sensors

The Analog Sensor Power Supply provides power to all the analog sensors (pressure and temperature).

• 5 Volt power supply

The ECM supplies 5.0 ± 0.5 Volts DC (Analog Supply) through the J1/P1 connector to each sensor. A power supply failure will cause all analog sensors to appear to fail.

• Power supply protected against short circuits

The power supply is protected against short circuits, which means that a short in a sensor or a wiring harness will not cause damage to the ECM.

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THROTTLE POSITION SENSOR +V DIGITAL DIGITAL RETURN SIGNAL

J35 P35 A B C

FAN SPEED SENSOR +V DIGITAL DIGITAL RETURN SIGNAL

J84 P84 A B C

LEFT EXHAUST TEMPERATURE SENSOR +V DIGITAL DIGITAL RETURN SIGNAL

J30 P30 A B C

RIGHT EXHAUST TEMPERATURE SENSOR +V DIGITAL DIGITAL RETURN SIGNAL

J31 P31 A B C

P1 J1 29 35

ECM + V DIGITAL SUPPLY - V DIGITAL RETURN

DIGITAL SENSOR POWER SUPPLY 8 ± 0.5 VOLTS

65 Digital Sensor Power Supply • 8 Volt power supply

The ECM supplies power at 8 ± 0.5 Volts through the J1/P1 connector to the following circuits: - Throttle Position Sensor - Fan Speed Sensor (if installed) - Exhaust Temperature Sensors

• Power supply protected against short circuits

The power supply is protected against short circuits, which means that a short in a sensor will not cause damage to the ECM.

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WASTEGATE CONTROL SOLENOID POWER SUPPLY 0 TO 1.04 Amps PWM

WASTEGATE CONTROL SOLENOID VALVE SUPPLY RETURN

J41 P41

P2 J2

A B

29 35

ECM WASTEGATE CONTROL PWM DRIVER & SOLENOID RETURN

66 Wastegate Control Solenoid Power Supply The ECM supplies a PWM signal of 0 to 1.04 amps through the J2/P2 connector to the Wastegate Control Solenoid Valve. • Valve operation tested with ET

The solenoid valve and power supply can be tested on the engine using ET and the Wastegate Position Test. Using the test, the pressure can be adjusted manually with the ET service tool from minimum to maximum. Therefore, this function can be used to verify the operation of the ECM, the power supply and the control valve.

• Valve position read with ET

The service tool status screen "Wastegate Position" reading can be used to show the position with 0% indicating the closed position and minimum current used, and 100% indicating fully opened with the maximum current used. This measurement can be used in conjunction with the desired and actual boost pressures to check the system operation.

➥

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INSTRUCTOR NOTE: The following exercise will reinforce the material introduced in the preceding slides and will allow questions to be answered. During this exercise, a demonstration on an engine or a Training Aid should be performed showing: Open circuit in the ECM power supply Opens and shorts in the Speed/Timing sensor power supply Opens and shorts in the Analog and Digital power supplies Status screen pressure and temperature readings with a fault in the sensor power supply

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3500B ELECTRONIC SENSORS AND SYSTEMS

67

ELECTRONIC SENSORS AND SYSTEMS This section of the presentation covers the electronic sensors and related circuits for 3500B EUI fuel systems used in machine applications.

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P26 T/C CONNECTOR

ECM


GROUND BOLT

P20/J20 SPEED/TIMING SENSOR

AFTERCOOLER TEMPERATURE SENSOR LOW OIL LEVEL SWITCH

J21/P21

J48/P48


J32/P32

J22/P22


J105/P105

J27/P27

J106/P106

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23


J28/P28

J29/P29

P31/J31

J103/P103 J113/P113

24 V

15 AMP BREAKER




BATTERY

J1

8/12/16 INJECTORS


DISCONNECT SWITCH

GROUND BOLT





308-YL

+ BATTERY


CYLINDER RELAY

STARTING AID SWITCH




113-OR J35/P35

P41/J41



P84/J84

A/C ON SWITCH


68 • Engine and machine wiring block diagrams

This block diagram shows all the electrical circuits on the engine and the machine (Off-highway Truck). The engine circuits will be described first, followed by the machine circuits. On the diagram, the dashed lines divide the engine mounted circuits and the machine mounted circuits.

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SPEED/TIMING SENSOR P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19 J2 J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20

69 Speed/Timing Sensing Circuit One Speed/Timing Sensor is installed and a serves four basic functions in the system: • Four functions of the speed/timing sensor

- Engine speed detection - Engine timing detection - Cylinder and TDC identification - Reverse rotation protection

• Self-adjusting zero gap sensor

The Speed/Timing Sensor is mounted on the rear housing and is self-adjusting during installation.

➥

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• No air gap

This type of sensor does not have a typical fixed air gap. However, the sensor is not in direct contact with the timing wheel, but does run with zero clearance. A Speed/Timing Sensor failure will cause an engine shutdown.

• Use status screen to check output

The sensor may be functionally checked by cranking the engine and observing the service tool status screen for engine rpm. A sensor failure will be indicated by the active fault screen on the service tool. An intermittent failure will be shown in the logged fault screen.

• Dedicated power supply

The sensor has a dedicated power supply. A power supply failure at the ECM will cause the sensor to fail. The sensor head is extended prior to installation. The action of screwing in the sensor pushes the head back into the body after the head contacts the timing wheel.

• Sensor installation precautions

• Calibration required after these procedures

During installation, it is essential to check that the sensor head is not aligned with a wide slot in the timing wheel. If this condition occurs, the head will be severed when the engine is started, and some disassembly may be necessary to remove the debris. As mentioned earlier, timing calibration is normally performed after the following procedures: 1. ECM replacement 2. Speed/timing sensor replacement 3. Engine timing adjustment 4. Camshaft, crankshaft or gear train replacement

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ANALOG SENSORS •

Coolant temperature sensor

•

Aftercooler temperature sensor

•

Oil pressure sensors

•

Atmospheric pressure sensor

•

Turbocharger inlet pressure sensors

•

Turbocharger outlet (boost) sensor

•

Crankcase pressure sensor

70

Analog Sensors and Circuits The following analog sensors may be used in various applications: - Coolant Temperature Sensor - Aftercooler Temperature Sensor - Oil Pressure Sensors (2) - Atmospheric Pressure Sensor - Turbocharger Inlet Pressure Sensors (1 or 2) - Turbocharger Outlet (Boost) Sensor - Crankcase Pressure Sensor

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COOLANT TEMPERATURE SENSOR P26 T/C CONNECTOR J4/P4 THROUGH J19/P19

ECM

J2 J1

8/12/16 INJECTORS

GROUND BOLT

P20/J20 SPEED/TIMING SENSOR COOLANT TEMPERATURE SENSOR

J21/P21

71 • Coolant temperature sensor • Sensor functions

The Coolant Temperature Sensor supplies the temperature signal for the following functions: - Caterpillar Monitoring System or VIMS instrument display, warning lamps and alarm - Demand Control Fan (if so equipped) - ET coolant temperature display - High coolant temperature event logged above 107°C (225°F) - Engine Warning Derate when 107°C (225°F) is exceeded or low oil pressure occurs (if so equipped) - Reference temperature for Cold Mode operation

NOTE: All analog sensors use the common analog power supply of 5.0 ± 0.2 Volts.

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AFTERCOOLER TEMPERATURE SENSOR P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19 J2 J1 8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20


J21/P21


J32/P32

72 • Aftercooler temperature sensor

The Aftercooler Temperature Sensor is mounted at the rear of the block (Off-highway Truck) and measures coolant temperature in the aftercooler circuit.

• Fan control reference temperature

The ECM uses the sensor signal as a reference for the fan control. When high aftercooler temperatures are reached, the cooling fan speed is increased. Very high aftercooler temperatures will cause a VIMS warning event to be logged.

NOTE: This sensor measures the ability of the aftercooler to cool the air sufficiently for combustion. As a general rule, for every 1 degree that the combustion air is reduced in temperature, the exhaust will be reduced by approximately 3 degrees. High inlet manifold temperatures can significantly shorten the life of exhaust system components (i.e. exhaust manifolds, valves, turbochargers and pistons). High temperatures will cause a loss of power also.

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OIL PRESSURE SENSORS P26 J4/P4 THROUGH J19/P19

ECM T/C CONNECTOR J2 J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR


P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


73 • Oil pressure sensors

Three pressure sensors are used for the measurement of oil pressure: - Two Oil Pressure Sensors (filtered and unfiltered) - Atmospheric Pressure Sensor

• Oil pressure sensors combined to measure filter restriction

The filtered and unfiltered pressure sensors are used together to measure oil filter restriction. The filtered oil pressure sensor is used to measure lubrication oil pressure for the operator on the dash panel and for the technician on ET. The atmospheric pressure sensor is used with this oil pressure sensor to calculate the gauge pressure reading.

➥

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LUBRICATION OIL PRESSURE CALCULATIONS MEASUREMENT

MEASURED BY

Oil pressure

[oil press (A) - atmospheric (A)]

Oil filter restriction

RESULT =

Oil pressure (GP)

[Unfiltered oil press - Filtered oil press] = Differential pressure (∆P)

These measurements are used to determine oil pressure for the ET service tool and for the dash display to alert the operator that an abnormal condition exists. The sensor operating range is 0 to 1000 kPa (0 to 144 psi) (A). Two lubrication oil pressure sensors are installed on this engine. One sensor measures pressure before the oil filter, and the other sensor measures pressure after the filter. These sensors are used together to calculate oil filter restriction (∆P).

NOTE: (A)

= absolute pressure

(GP)

= gauge pressure

(∆P)

= differential pressure

INSTRUCTOR NOTE: Refer to Serviceman's Handout No. 5 for a complete list of ECM calculations.

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49.3

320

46.4

300

43.5

280

40.6

260

37.7

240

34.8

220

31.9

200

29

180

26.1

160

23.2

140

20.3

120

17.4

100

14.5

80

11.6

OIL PRESSURE IN PSI

OIL PRESSURE IN kPa

OIL PRESSURE MAP 340

8.7

60 600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

ENGINE RPM kPa x 0.145 = PSI

74 • Oil pressure map • Determines correct pressure for all rpm

Engine oil pressure varies with engine speed. As long as oil pressure increases above the upper line after the engine has been started and is running at low idle, the ECM reads adequate oil pressure. No faults are indicated and no logged event is generated. A delay (de-bounce time) built into the system prevents false events from being logged after start-up or after a filter change. If the engine oil pressure decreases below the lower line, the following occurs:

• Low oil pressure trips these functions

- An event is generated and logged in the permanent ECM memory. - A Category 3 Warning (alert indicator, action lamp and alarm) is generated on the VIMS and Caterpillar Monitoring System. - The engine is derated (if so equipped) to alert the operator. The width of the pressure band between the two lines is sufficient to prevent multiple alarms and events or a flickering warning lamp. (This pressure separation is referred to as hysteresis.)

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ATMOSPHERIC PRESSURE SENSOR ECM

P26 T/C CONNECTOR


J2 J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


J27/P27


75 • Atmospheric pressure sensor

• Used to calculate gauge pressure • Two methods used to calibrate sensors • Four main functions

All pressure measurements require the atmospheric pressure sensor to calculate gauge pressure. All pressure sensors in the system measure absolute pressure. The sensors are used individually in the case of atmospheric pressure (absolute pressure measurement). They are used in pairs to calculate gauge pressures (oil and boost) and filter restriction. All the pressure sensor outputs are matched to the Atmospheric Pressure Sensor output during calibration. Calibration can be accomplished automatically using the ET service tool or by turning on the key start switch without starting the engine for five seconds. The Atmospheric Pressure Sensor performs four main functions: 1. Automatic Altitude Compensation (Maximum derate 24%) 2. Automatic Filter Compensation (Maximum derate 20%) 3. Part of the pressure calculation for gauge pressure readings 4. Reference sensor for pressure sensor calibration A foam filter is installed below the sensor to prevent the entry of dirt.

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ENGINE POWER DERATING MAP 100%

7,500

98%

8,210

96%

8,920

94%

9,630

92%

10,340

90%

11,050

88%

11,760

86%

12,470

84%

13,180

82%

13,890

80%

14,600

78%

15,310

76%

16,020

74%

16,730

72%

17,440 77 76

75 74 73 72 71 70 69 68 67 66 65 64

ALTITUDE IN FEET

PERCENT OF FULL LOAD POWER

ACCORDING TO ATMOSPHERIC PRESSURE

63 62 61 60 59 58 57 56 55 54 53

ATMOSPHERIC PRESSURE IN kPa

76 • Automatic altitude compensation

Atmospheric pressure measurement by the sensor provides an altitude reference for the purpose of Automatic Altitude Compensation. The graph shown here describes how derating on a typical 3500B starts at 7500 ft. and continues linearly to a maximum of 17000 ft. Other engines may start between 4000 and 12000 ft. depending on the application.

• System continually adjusts to optimum power setting

The advantage of the EUI system is that the engine always operates at the correct derating setting at all altitudes. The system continually adjusts to the optimum setting regardless of altitude, so the engine will not exhibit a lack of power or have smoke problems during climbs or descents to different altitudes. NOTE: The EUI system has an advantage over a mechanical fuel system which is derated in "altitude blocks" (i.e. 7500 ft., 10000 ft., 12500 ft.). EUI derating is continuous and automatic. Therefore, a machine operating in the lower half of the block is not penalized with low power. Conversely, a machine operating in the upper half of the block will not overfuel with the EUI system.

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ECM

P26 J4/P4 THROUGH J19/P19

T/C CONNECTOR J2 J1

8/12/16 INJECTORS

GROUND BOLT

P20/J20 SPEED/TIMING SENSOR COOLANT TEMPERATURE SENSOR AFTERCOOLER TEMPERATURE SENSOR

J21/P21

J48/P48


J32/P32

J22/P22


J27/P27

TURBOCHARGER INLET PRESSURE SENSORS

ATMOSPHERIC PRESSURE SENSOR LEFT TURBOCHARGER INLET PRESSURE SENSOR

J28/P28

J25/P25

RIGHT TURBOCHARGER INLET PRESSURE SENSOR

77 • Turbo inlet pressure sensor

The Turbocharger Inlet Pressure Sensor is used with the Atmospheric Pressure Sensor to measure air filter restriction. This function is known as Automatic Air Filter Compensation.

• Sensors enable automatic air filter compensation

These two sensors are used to enable the Automatic Air Filter Compensation function by measuring the differential pressure across the filter.

• Back-up to the atmospheric pressure sensor for altitude

The Turbocharger Inlet Pressure Sensor is also used as a back-up to the Atmospheric Pressure Sensor for Automatic Altitude Compensation. Depending on the inlet and air filter configuration, some applications may have two inlet pressure sensors (i.e. separate left and right systems with no connecting balance pipe).

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AUTOMATIC AIR FILTER COMPENSATION TURBOCHARGER INLET PRESSURE SENSOR


CAT

Filter differential pressure calculated with formula: Atmospheric sensor pressure - Turbo sensor pressure = ∆P Fuel limited 2% per 4 inches H20 to max 20%

78 • Automatic filter compensation • Derating (typically) starts above 30 in. ∆P

Automatic Filter Compensation means that the engine is protected against the effects of plugged filters. Derating is automatic as follows: - Air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water) - Engine power derating starts at the rate of 2% per 1 kPa of ∆P - Maximum derate 20% - Event is logged when air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water) These ∆P specifications are typical examples. The actual values may vary depending on the application. Derating is retained at the maximum ∆P until the key start switch is cycled off and on. NOTE: If only one filter is plugged, the ET service tool and Caterpillar Monitoring System will display the highest ∆P of the two. Derating is also based on the highest ∆P of the two.

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P26 T/C CONNECTOR

ECM


8/12/16 INJECTORS

SPEED/TIMING SENSOR COOLANT TEMPERATURE SENSOR AFTERCOOLER TEMPERATURE SENSOR

GROUND BOLT

P20/J20

J21/P21

J48/P48


J32/P32

J22/P22


J27/P27

TURBOCHARGER OUTLET PRESSURE SENSOR


J28/P28

J25/P25

J23/P23


79 • Turbocharger outlet pressure sensor

The Turbocharger Outlet Pressure Sensor measures absolute pressure downstream of the aftercooler. Boost (gauge) pressure can be read with the ET service tool. This measurement is a calculation using the Atmospheric Pressure and the Turbocharger Outlet Pressure Sensors. A failure of this sensor will cause the ECM to default to a zero boost condition. This failure can result in a 60% loss in engine power.

• Air/fuel ratio control

The function of the sensor is to enable the Air/Fuel Ratio Control which reduces smoke, emissions and maintains engine response during acceleration. The system utilizes manifold pressure and engine speed to control the air/fuel ratio. Engine fuel delivery is limited according to a map of gauge turbo outlet pressure and engine speed.

• Air/fuel ratio control is adjustable with ET

The Air/Fuel Ratio Control setting is adjustable on 3500B machine applications using the ET service tool.

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P26 T/C CONNECTOR

ECM


8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


J27/P27


J28/P28

J25/P25

J23/P23



J29/P29


80 • Crankcase pressure sensor

The ECM uses gauge pressure measured from the Crankcase Pressure Sensor and the Atmospheric Pressure Sensor to determine whether crankcase pressure is excessive. The ECM will warn the operator of possible damaging conditions and record adverse conditions in the memory. A possible cause of excessive crankcase pressure could be piston damage or a piston ring failure. An early warning means that the engine can be shut down without catastrophic secondary damage. Crankcase pressure (A) is compared with atmospheric pressure (A). The result is crankcase (gauge) pressure (i.e. pressure above ambient).

• Trip points

The trip points are: WARNING EVENT

2 kPa (10 in. of water) 3.5 kPa (17in. of water)

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P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19 J2 8/12/16 INJECTORS

SPEED/TIMING SENSOR

J1

GROUND BOLT

P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

LOW OIL LEVEL SWITCH


ENGINE SWITCHES

LEFT TURBOCHARGER INLET PRESSURE SENSOR RIGHT TURBOCHARGER INLET PRESSURE SENSOR

J25/P25

J23/P23



J29/P29

81 Engine Mounted Switches Three EUI circuit switches are mounted on the engine: • Low oil level switch

The Low Oil Level Switch signals the ECM if the engine oil level decreases below a predetermined level. The ECM then warns the operator of possible damaging conditions and logs an event.

• Filter differential pressure switch

The Filter Differential Pressure Switch signals the ECM if the pressure across engine fuel filter is excessive and the filter needs to be changed.

• Coolant flow switch

The Coolant Flow Switch provides the operator with a warning if a failure in the coolant circuit causing no flow occurs. The switch contacts are normally open with no flow.

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EUI SWITCH CIRCUITS LOW OIL LEVEL SWITCH

J105 P105 SIGNAL DIGITAL RETURN

FUEL FILTER SIGNAL DIFFERENTIAL DIGITAL RETURN PRESSURE SWITCH COOLANT FLOW SWITCH

P1 J1

F719-BR 998-BR

1 2

ECM

24

LOW OIL LEVEL

F725-WH 998-BR

17

FUEL FILTER SW

412-BU 998-BR

26 29

COOLANT FLOW DIGITAL RETURN

J106 P106

1 2

J47 P47 SIGNAL DIGITAL RETURN

1 2

82 • Coolant flow switch

The Coolant Flow Switch, like the Oil Level Switch, is a passive sensor (i.e. no power supply) which means that the ECM cannot determine if the switch or associated circuit has failed. A system problem could be determined if coolant flow is indicated with the engine stopped or if no coolant flow is indicated with the engine running.

• Switch functions checked with status screen

The functions of these switches may be checked using the status screen. The Coolant Flow Switch should indicate if flow is present. This function should be checked both with the engine running and stopped.

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DIGITAL SENSORS AND CIRCUITS • Wastegate control • Exhaust temperature • Throttle position

83

Digital Sensors and Circuits The following digital sensors and circuits are used on the 793C EUI fuel system: - Wastegate Control Solenoid - Exhaust Temperature Sensors - Throttle Position Sensor

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P26 T/C CONNECTOR

ECM


8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47



J25/P25

J23/P23



J29/P29

CRANKCASE PRESSURE SENSOR WASTEGATE CONTROL SOLENOID

84 • Wastegate control

The ECM controls turbocharger boost (on the 793C) with the Wastegate Control Solenoid. The ECM varies the current level to the solenoid to maintain the desired boost pressure. This current, expressed as a percentage (0 to 100%), can be monitored with ET on the status screen. The ET service tool also allows the wastegate to be manually operated for testing purposes.

• Wastegate control solenoid current monitoring

Both desired and actual boost pressures can be monitored. If high boost pressure is detected, a warning is generated and the engine is derated for protection against excessive cylinder pressure. A lower than normal boost pressure will also cause a warning to be generated.

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P26 T/C CONNECTOR

ECM

J4/P4 THROUGH J19/P19 J2 J1 8/12/16 INJECTORS

SPEED/TIMING SENSOR

GROUND BOLT

P20/J20


J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

P31/J31

J29/P29




EXHAUST TEMPERATURE SENSORS



85 Two Exhaust Temperature Sensors are installed on the 793C. The sensors are mounted between the exhaust manifold and the turbocharger. The ECM uses the sensors to warn the operator of possibly damaging conditions and logs an event in the memory. • ECM derates with excessive exhaust temperature

An engine derate occurs on Off-highway Trucks if excessive exhaust temperatures are reached.

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P26 T/C CONNECTOR

ECM


GROUND BOLT

P20/J20

J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

P31/J31

J29/P29


24 V

15 AMP BREAKER




BATTERY

J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

DISCONNECT SWITCH

GROUND BOLT



113-OR J35/P35

308-YL KEY START SWITCH




86 • Throttle position sensor

The Throttle Position Sensor provides engine speed control for the operator. At engine start-up, the engine rpm is set to low idle for two seconds to allow an increase of oil pressure before the engine is accelerated.

• 8 Volt digital sensor power supply

The Throttle Position Sensor receives 8 Volts from the Digital Sensor Power Supply at the ECM. The Throttle Position Sensor is shown on the machine wiring side of the diagram.

NOTE: This system eliminates all mechanical linkages between the operator's engine speed controls and the governor (ECM).

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PULSE WIDTH MODULATED SIGNALS 10% ON DUTY = 10% CYCLE OFF 50% ON DUTY = 50% CYCLE OFF 1 CYCLE

90% ON DUTY = 90% CYCLE OFF

DUTY CYCLE = PERCENT OF TIME ON VS PERCENT OF TIME OFF

87 • Throttle position sensor signal

A Pulse Width Modulated (PWM) output signal is sent from the Throttle Position Sensor to the ECM. A PWM signal eliminates the possibility of an erroneous throttle signal due to a short causing a possible "runaway."

• Control defaults to low idle with invalid signal

If a signal problem occurs, the control defaults to the desired engine speed of low idle. If the ECM detects an out-of-normal range signal, the ECM ignores the Throttle Position Sensor signal and defaults to low idle.

• Pulse width modulated (PWM) signal

The sensor output is a constant frequency Pulse Width Modulated (PWM) signal to the ECM. For example, the Off-highway Truck sensor produces a duty cycle of 10 to 22% at the low idle position and 44 to 52% at the high idle position. The duty cycle can be read with some VOM's. The percent of duty cycle is translated into a throttle position of 0 to 100% by the ECM and can be read on the ET status screen. Other applications differ in PWM values for low and high idle. These values can be found in the Troubleshooting Guide for the appropriate application.

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P26 T/C CONNECTOR

ECM


8/12/16 INJECTORS

GROUND BOLT

P20/J20

J21/P21

J48/P48


J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

P31/J31

J29/P29

SPEED/TIMING SENSOR




BATTERY

24 V

15 AMP BREAKER



DISCONNECT SWITCH

GROUND BOLT

113-OR J35/P35

308-YL

KEY START SWITCH






88 • Throttle back-up switch • Throttle back-up activated with TPS fault

The Throttle Back-up Switch provides a "limp home" mode in the event that the Throttle Position Sensor becomes inoperative. If the ECM detects either an invalid or no signal from the Throttle Position Sensor, the Throttle Back-up Switch is automatically activated. When activated, the operator may operate the switch to raise the engine speed to 1200 rpm for as long as the switch is operated. If the Throttle Position Sensor signal is received again, the switch is deactivated.

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P26 T/C CONNECTOR

ECM


GROUND BOLT

J2 J1

8/12/16 INJECTORS

GROUND BOLT

P20/J20 SPEED/TIMING SENSOR J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23

P31/J31

J29/P29



BATTERY

24 V

15 AMP BREAKER




DISCONNECT SWITCH

113-OR J35/P35

308-YL




GROUND LEVEL SHUTDOWN SWITCH



89 Engine Shutdown Systems • Ground level shutdown switch

The Ground Level Shutdown Switch is connected to the ECM through the machine and engine wiring harnesses. The switch signals the ECM to cut electrical power to the injectors, but maintains power to the ECM. This feature also enables the engine to be cranked without starting for maintenance purposes. No other circuits may be connected to this system. The user defined shutdown feature may be used in conjunction with other circuits.

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USER DEFINED SHUTDOWN

USER SHUTDOWN DEVICE

J3

P2 J2

12

1

ECM USER SHUTDOWN

90 • User defined shutdown input

The User Defined Shutdown feature (if installed) may be used to connect another device to the system to shut down the engine (such as a customer installed fire suppression system). When the shutdown input is grounded for one second, the engine will stop running. The input must be pulled down below 0.5 Volts before the ECM will recognize the shutdown signal. Operation of the User Defined Shutdown is logged as an event and can also be shown on the ET status screen.

• Safety feature

For example, when installed on an Off-highway Truck, this feature is programmed to function only during the following conditions: Parking brake is ENGAGED Transmission is in NEUTRAL Machine ground speed is at ZERO Not all machines will have this feature installed.

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ETHER INJECTION SYSTEM ECM ETHER SWITCH 998-BR

P1 J1 F720-GN 998-BR 710-BR 707-WH

25 29 40 22

ETHER REQUEST DIGITAL RETURN ETHER ON ETHER HOLD

+24V

315-GN

317-YL

317-YL

P37 J37 1 2

ETHER ON RELAY F707-WH 315-GN

START AID RESISTOR

200-BK

ETHER SOLENOID VALVE

K984-GY

ETHER HOLD RELAY

91 Ether Injection System The ECM controls the use of ether for cold starting. The ECM uses inputs from the speed/timing and coolant temperature sensors to determine the need for ether. • Ether injection parameters

The ECM cycles the ether for three seconds on and three seconds off. Actual flow is determined by engine speed and temperature. Ether injection is disabled when the coolant temperature exceeds 10°C (50°F) or engine speed exceeds 1200 rpm. A manual mode allows ether injection when the above parameters permit. In the manual mode, a continuous flow of ether is injected. The ether injection status can be read on the ET status screen.

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P26 T/C CONNECTOR J4/P4 THROUGH J19/P19

J2

GROUND BOLT

P20/J20

J21/P21

J48/P48



J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23


J28/P28



J29/P29

113-OR J35/P35


308-YL

+ BATTERY


CYLINDER STARTING AID SWITCH

ETHER START VALVE USER SHUTDOWN



ENGINE RELAY

P41/J41 P31/J31

24 V

15 AMP BREAKER




BATTERY

J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

DISCONNECT SWITCH

GROUND STUD

ECM


P84/J84


A/C ON SWITCH

DEMAND FAN CONTROL

FAN SPEED SENSOR

92 • Two thermostatic fan types: - Variable speed clutch - Hydraulic motor

Demand Fan Controls Two types of thermostatic fans are used in 3500B machine applications. Some Off-highway Trucks and Track-type Tractors are equipped with a variable speed fan drive clutch. Some Wheel Loaders are equipped with a hydraulic fan drive. Both systems use the ECM and the temperature sensor as the engine coolant temperature reference, and both are controlled by the ECM. If an electrical failure of the system occurs, the fan will go to maximum (100%) speed. The advantages of the systems are:

• System advantages

- Reduced fuel consumption in most conditions - Reduced engine overcooling at low ambient temperatures - Faster engine warm-up - More engine power available at the flywheel - Reduced noise

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CAT DATA LINK SERVICE TOOL CONNECTOR

COMMUNICATION ADAPTER CAT ELECTRONIC TECHNICIAN

VIMS

ADEM II ELECTRONIC CONTROL MODULE (ECM)

MAIN MODULE

LAPTOP COMPUTER

VIMS DISPLAY MODULES

93 • CAT Data Link

CAT Data Link

• Link between various microprocessor based systems

The CAT Data Link is the communication link between the ECM, EPTC II, Caterpillar Monitoring System, ET Service Tool, or PC based software and other onboard/offboard microprocessor based systems. The CAT Data Link is a system which allows the various onboard systems to communicate with each other through a two wire connection. Up to 10 systems can be connected on a machine.

• ET connected through service tool connector

The CAT Data Link is used for programming and troubleshooting the electronic modules used with Caterpillar ET through the Service Tool Connector. This connector is the common access point for all onboard ECM's.

• No start/no communication without a personality module file

It should be noted that, if a Personality Module is not installed in the ECM or is not flash programmed, the ET Service Tool will not be able to communicate with the ECM.

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TYPICAL CAT DATA LINK CIRCUIT POWER TRAIN CONTROL MODULE Cat Data Link + Cat Data Link -

SERVICE TOOL CONNECTOR

VIMS 8 9

J42 D E H J

23 24

P3 J3 7 6 31 32

Cat Data Link + Cat Data Link -

893-GN 892-BR E794-YL E-793-BU

P1 J1 9 3 7 1

ECM Cat Data Link + Cat Data Link ATA Data Link + ATA Data Link -

MACHINE INTERFACE CONNECTOR

94 • Data link cables twisted to reduce RFI

The CAT Data Link is a two wire (twisted pair) electrical connection used for communication between electronic modules that use the CAT Data Link. The cables are twisted to reduce Radio Frequency Interference (RFI). Typical systems connected by the data link are: - ECM - VIMS Modules - Caterpillar ET Service Tool - Transmission Control Module The ECM communicates with the Caterpillar Monitoring System or Vital Information Management System (VIMS) to share engine information such as engine speed, engine oil pressure, coolant temperature, filter restriction, and electronic system faults.

• Two data link systems: - CAT Data Link - ATA Data Link

Two data link systems are currently used. The CAT Data Link circuit is used for normal diagnostic and programming functions, and the ATA Data Link is used for flash programming.

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PRELUBRICATION SYSTEM ECM P1 J1 F709-BU 998-BR

+

140-BU

+24V

337-WH

PRELUBRICATION RELAY

34 29

1 2

PRELUBRICATION DIGITAL RETURN

PRELUBRICATION MOTOR

200-BK MOTOR

PUMP RELAY

95 Prelubrication System • ECM controls prelube system

The ECM controls the prelubrication system (if installed). This system uses the coolant temperature, engine speed and oil pressure as its references to determine the need for prelubrication. The system is activated when the key start switch is turned to the start position. The system prevents starter motor engagement until the oil pressure increases.

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LOGGED EVENTS

96

Logged Events Logged events listed on the appropriate ET screen are conditions which are abnormal to the operation of the engine. For example: • Typical logged events

- High coolant temperature - Low oil pressure - Filter restriction - Excessive engine speed

These events are not normally electronic problems, but might be conditions caused by a plugged radiator, low oil level, maintenance or operator deficiencies. A list of possible events for the 3500B engine is included on the next page.

STMG 681 1/02 • Engine events

• Event list

- 106 -

Some of the parameters listed in this presentation are used in the ET events list. They are as follows: - High coolant temperature - High exhaust temperature - High aftercooler temperature - Crankcase pressure - Loss of coolant flow - Low (lubrication) oil pressure (according to the oil pressure map) - User defined shutdown - Air filter restriction - Fuel filter restriction - Oil filter restriction - Engine oil level - Engine overspeed histogram - High boost - Low boost All the above parameter values can be read on the ET status screens. Events are not logged if an electronic fault is detected. Passwords are required to clear events. This process would normally be performed during an engine overhaul. At other times, the events should remain as a record of the engine history up to overhaul time. INSTRUCTOR NOTE: To reinforce this presentation, the following tasks can be demonstrated using a training aid or a suitable engine: Opens and shorts in analog and digital sensors Opens and shorts in throttle sensor Status screens: Read pressure and temperature readings Switch positions Override fan speed control Check events log

STMG 681 1/02

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APPLICATION SPECIFIC SYSTEMS

97

APPLICATION SPECIFIC SYSTEMS This portion of the presentation discusses application specific systems in machine applications. The topics are: Oil Renewal System (Off-highway Trucks) Wastegate Control System (793C)

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2

1

98

Oil Renewal System

• Oil renewal components: 1. Oil renewal injector manifold 2. Fuel pressure regulator

This system is controlled by the ECM which, depending on various parameters, injects engine oil into the return fuel line where it mixes with the fuel and is sent to the fuel tank. Located on the right side of the engine are: - Oil renewal injector manifold (1) - Fuel pressure regulator (2) The oil does not have to be changed when using the oil renewal system. When the oil renewal system is used, the engine oil filters, the primary fuel filter and the secondary fuel filters must all be changed at 500 hour intervals.

STMG 681 1/02

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3516B OIL RENEWAL CIRCUIT (793C) FUEL PRESSURE REGULATOR CYLINDER HEAD

OIL RENEWAL INJECTOR ENGINE BLOCK PRIMING PUMP SUPPLY

FUEL TANK SECONDARY FUEL FILTERS (2 MICRON)

PRIMARY FUEL FILTER

FUEL TRANSFER PUMP

ECM

FUEL HEATER

99 • Oil flow from lube system to fuel tank

A small amount of engine oil flows from the engine block to the oil renewal injector manifold. The oil flows from the oil renewal injector manifold into the return side of the fuel pressure regulator. The engine oil returns to the fuel tank with the return fuel.

• Oil mixes with fuel in fuel tank

The engine oil mixes with the fuel in the fuel tank and flows with the fuel from the transfer pump to the EUI injectors to be burned with the fuel. When the oil renewal system is used, the operator must pay close attention to the ADD OIL message that the VIMS provides to the operator when makeup oil must be added. This system, which is an attachment, includes a larger capacity oil pan. If the ECM detects a low oil level, an event is logged.

• Oil Renewal Service Manual

For more detailed information, refer to "Oil Renewal System Service Manual" Form RENR2223.

STMG 681 1/02

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1

2

100

Wastegate Control 1. Exhaust bypass valve

An exhaust bypass (wastegate) valve (1) prevents excessive boost pressure by diverting exhaust gasses away from the turbochargers. The bypass valve is controlled by the ECM.

2. Wastegate solenoid valve - Controlled by ECM

Brake system air pressure is supplied to the wastegate solenoid valve (2). If boost pressure exceeds a predetermined value, the ECM will energize the wastegate solenoid which sends air pressure to open the exhaust bypass valve. When the exhaust bypass valve is open, exhaust gases at the turbine side of the turbochargers are diverted to the muffler. Diverting the turbine exhaust pressure causes the turbochargers to slow down and reduce the boost pressure to the cylinders.

• Engine wastegate solenoid can be controlled by ET

For diagnostic testing, the wastegate solenoid valve can be manually controlled (overridden) from minimum to maximum with the ET service tool. The status screen can be used to read the current flowing through the solenoid. 0% corresponds to a closed wastegate and 100% corresponds to fully open.

• Abnormal conditions generate derate and event

The following conditions will cause the ECM to generate a derate and log an event: 20 kPa (3 psi) above desired pressure for 15 seconds causes 10% derate 30 kPa (4 psi) below desired pressure for 15 seconds causes 10% derate

STMG 681 1/02

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P26 T/C CONNECTOR

ECM


GROUND BOLT

P20/J20

J48/P48


J32/P32

J22/P22


J105/P105

J27/P27


J106/P106

J28/P28

COOLANT FLOW SWITCH

J47/P47

J25/P25

P30/J30

J23/P23



J29/P29

P31/J31

J103/P103 J113/P113

24 V

15 AMP BREAKER


J21/P21


BATTERY

J1

8/12/16 INJECTORS

SPEED/TIMING SENSOR

DISCONNECT SWITCH

GROUND BOLT

J2




308-YL



+ BATTERY

CYLINDER RELAY

STARTING AID SWITCH




113-OR J35/P35

P41/J41



P84/J84

A/C ON SWITCH


101

CONCLUSION The 3500B Electronic Engine Control System is the "state of the art" in engine electronics. It combines the speed and capacity of modern computer systems, but at the same time is easy to service and maintain. Tasks such as re-rating the engine, which traditionally took four to eight hours, can be performed in minutes with this system. The key to success with the 3500B EUI system is understanding the functions of all the components and the diagnostic tooling. This only develops with practice, working with the system, operating with ET and using all the tool functions. INSTRUCTOR NOTE: To reinforce this presentation, the following tasks can be demonstrated with ET: Status screens with Oil Renewal condition status Program Oil Renewal system Read Wastegate current values Compare actual with desired boost values Manually override Wastegate Control Check events list for abnormal Wastegate occurrences

STMG 681 1/02

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SLIDE LIST 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41.

Title slide 3500B engine overview 3500B engine cross section HEUI fuel system components 3500B block diagrams 3500B major components 3500B engine front view 3500B engine rear view 3500B engine left side view 3500B engine right side view Electronic control module EUI wiring harness Coolant temperature sensor Speed/timing sensor Speed/timing sensor and timing wheel Timing wheel 3500B camshaft Injector pushrod spring EUI injector Fuel pressure regulator Atmospheric pressure sensor Turbocharger inlet pressure sensor Turbocharger outlet (boost) pressure sensor Exhaust temperature sensor Lubrication oil pressure sensors Crankcase pressure sensor Timing calibration sensor Throttle sensor Fuel filters ECM controlled systems Engine component identification Electronic control system ECM Personality module Fuel injection Injector testing methods Timing control logic Electronic governor Component diagram Speed/timing sensor Speed/timing sensor and timing wheel

42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77 78. 79. 80. 81. 82.

Timing wheel Cranking After pattern recognition Normal operation Timing calibration sensor Timing calibration Injection current waveform Fuel System Cold Modes Fuel system limits Fuel system derates Fuel supply system Fuel supply circuit Fuel transfer pump Fuel pressure regulator MUI and EUI Cylinder heads Electronic unit injector System power supplies list ECM power supply ECM power supply circuit ECM connectors Speed/timing sensor power supply Injector wiring schematic Analog sensor power supply Digital sensor power supply Wastegate control solenoid power supply Electronic sensors and systems 3500B block diagrams Speed/timing sensor Analog sensor list Coolant temperature sensor Aftercooler temperature sensor Oil pressure sensors Oil pressure map Atmospheric pressure sensor Engine power derating map Turbocharger inlet pressure sensor Automatic filter compensation Turbocharger outlet (boost sensor) Crankcase pressure sensor Engine switches Coolant flow switch

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SLIDE LIST 83. 84. 85. 86. 87. 88. 89. 90. 91. 92.

Digital sensors and circuits list Wastegate control Exhaust temperature sensors Throttle position sensor Pulse Width Modulated (PWM) signal Throttle back-up switch Engine shutdown systems User defined shutdown input Ether injection system Demand fan controls

93. 94. 95. 96. 97. 98. 99. 100. 101.

CAT Data Link diagram CAT Data Link circuit Pre-lubrication system Logged events Application specific systems Continuous oil renewal system Continuous oil renewal circuit Wastegate control 3500B block diagram

J22/P22

J27/P27

J28/P28

J25/P25

J23/P23

J32/P32

J105/P105

J106/P106

J47/P47

P30/J30

J113/P113

J103/P103

J29/P29

J48/P48

J21/P21

P20/J20


GROUND STUD

OIL RENEWAL CONTROL SOLENOID

P84/J84

P41/J41

RELAY

+ BATTERY

A/C ON SWITCH

CYLINDER

GROUND LEVEL SHUTDOWN SWITCH

KEY SWITCH

24 V

BATTERY

TO VIMS EPTC II OR CAT MONITORING SYSTEM

SERVICE TOOL TOOL CONNECTOR

ETHER START VALVE USER DEFINED SHUTDOWN

ENGINE

308-YL

DISCONNECT

15 AMP BREAKER

113-OR


+ BATTERY

J35/P35

GROUND STUD

FAN SPEED SENSOR

TO PRELUBRICATION PUMP

STARTING AID SWITCH

THROTTLE BACKUP SWITCH





LEFT TURBOCHARGER INLET PRESSURE SENSOR RIGHT TURBOCHARGER INLET PRESSURE SENSOR




J2 J1

ECM


- 114 -



COOLANT FLOW SWITCH





SPEED/TIMING SENSOR

8/12/16 INJECTORS


P26 T/C CONNECTOR


STMG 681 1/02 Serviceman's Handout No. 1

- 115 -

MUI

MUI AND EUI

CYLINDER HEADS

EUI

STMG 681 1/02

Serviceman's Handout No. 2

PRIMARY FUEL FILTER

FUEL TRANSFER PUMP

FUEL DIFFERENTIAL PRESSURE SWITCH

PRIMING PUMP SUPPLY

ECM

CYLINDER HEAD


- 116 -

FUEL HEATER

FUEL TANK

ENGINE BLOCK

OIL RENEWAL INJECTOR

FUEL PRESSURE REGULATOR

3516B FUEL SUPPLY CIRCUIT (793C)

STMG 681 1/02 Serviceman's Handout No. 3

STMG 681 1/02

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EUI COLD MODES

COLD MODE TITLE

PURPOSE

TRIP POINTS

SENSOR

Speed Control Elevated low idle

Faster warm-up

< 60°C

Coolant temperature

Improves starting by limiting fuel

< 60°C

Coolant temperature

Fuel Limiting Cranking limit

Prevents over-fuelling during start-up

Cold Mode Cutout

Cuts out dead cylinders during cold, low load, low speed conditions

< 60°C Coolant temperature < 1300 rpm < 25% throttle

Optimum timing for cold running

< 60°C

Coolant temperature

10°C

Coolant temperature

Injection Timing Cold Mode Timing

Reduces white smoke

Ether Injection Ether injection

Starting aid

STMG 681 1/02

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ECM PRESSURE CALCULATIONS

MEASUREMENT

MEASURED BY

RESULT

1. Atmospheric pressure

atmospheric sensor

= ambient press (absolute)

2. Air filter differential

atmospheric - turbo inlet

= filter ∆ pressure

3.

Boost

turbo outlet - atmospheric

= boost (gauge pressure)

4.

Manifold press. (A)

turbo outlet sensor

= boost (absolute pressure)

5.

Oil pressure

oil press - atmospheric

= oil press (gauge pressure)

6. Oil filter differential 7. Crankcase pressure (A)

oil press unfiltered - oil press filtered

= oil filter ∆ pressure

crankcase pressure - atmospheric = crankcase pressure (gauge pressure)

These measurements are used to provide the following: 1. Altitude and Automatic Altitude Compensation 2. Automatic Air Filter Compensation (and Restriction Indication) 3. ET Boost Measurement (gauge pressure) 4. ECM Boost Measurement (absolute pressure) 5. Operator's Dash Panel and ET Oil Pressure Indication (Lubrication) 6. Oil Filter Restriction Warning 7. High Crankcase Pressure Warning

STMG 681 1/02

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How small is a Micron? Human Hair 88 Micron .0035 Inch .0889 mm Magnified 2,000 times 1 Micron .00004 Inch .001 mm

25 Micron .001 Inch .025 mm

2.5 Micron .0001 Inch .0025 mm 5 Micron .0002 Inch .005 mm

25,400 Microns = 1 Inch

SERV1681-01 01/02

Printed in U.S.A.

SERV1681_TXT technical presentation.pdf

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