FORD POWER STROKE DIESEL NO-START DIAGNOSIS Don’t Start Something You Can’t Finish BY BOB PATTENGALE
Service opportunities on diesel-power diesel-powered ed vehicles are on the rise. If your shop is looking for additional revenue, taking on the oil-burners could be the ticket. But to be successful, you’ll need the right tools and training.
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ow do you approach a familiar no-start or driveabil biliity probl problem em? Do Do you jum ju mp ri rig ght in in,, relyin ing g on past knowledge knowledge of comcommon problem problems, or do you folllow a set diag fol diagnostic stra strategyto ensure nothing nothi ng is overl rlooked. ooked. What Wh at about when a vehi ehicl cle e manufacturer tur er makes changes to the engine engine man-
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agement system? Do D o you take time time to understand the system fi first rst or do you dive right into the diagnostic process, hoping hopi ng your experi rience ence wins out? What happens if your fi first couple couple of educated guessesdon’t resolve resolve the problem? problem? E ffective and eff effici icien entt repair repair of today’s vehi ehicl cles es requi requirres an under understa standing of how each system operates before for e the diagnos nosti tic c process begins. It’s I t’s
a i d e M k c e i W & k c o t s k n i h T : s e g a m i ; y r r e P . A d l o r a H : n o i t a r t s u l l i o t o h P
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FORD POWER STROKE DIESEL NO-START DIAGNOSIS
High-Pressure Oil Rails
Oil Filter
Oil Reservoir for High-Pressure Pump HighPressure Oil Pump
Oil Cooler
Fuel Injectors
Oil Pump
IPR Sensor ICP Sensor
Drain to Crankcase
. o C r o t o M d r o F y s e t r u o C
Fig. 1 This illustration shows the low-pressure and high-pressure oil systems for the 6.0L diesel engine. The fuel system must have the correct oil pressure to operate, so oil-related problems are common causes of hard-start/no-start issues.
nice to have troubleshooter tips, but there’s no substitute for a firm grasp of how the components relate to one another and what happens when everything is working right. Many assume top driveability technicians quickly diagnose problems because they’re able to complete all the tasks in a fault tree the fastest or because they know all the common issues. The truth is they’re able to look at the symptoms, make a logical decision on where the diagnostic process
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should begin and then follow the best path for resolution. The opportunity to repair diesel vehicles is on the rise, and if your shop is looking for additional revenue, diesel repair can be it. To be successful you need to have the right tools and technicians who understand how diesel systemswork. Ford diesel truck repair is agood opportunity. I t’s also an excellent example of how things can change very quickly. In the past 10 years, Ford has offered
four different platforms—7.3L, 6.0L, 6.4L and now the 6.7L—and although the basic combustion process for each is similar, how the fuel is supplied to the cylinders is very different. This article will focus on a common driveability complaint with the Ford 6.0L diesel engine, then explain how the 6.4L fuel delivery system differs fromthe 6.0L. Hard-start and no-start complaints are a common issue with F ord 6.0L diesel engines, and experienced techni-
cians are able to determine the root cause very quickly. But they can do this only because they understand how the system operates. Technicians with limited experience . c n will most likely begin with the “Hard I , Start/No Start Diagnostic Guide” devel- p u o r oped by Ford. We don’t have the space G g to reproduce it here, but it can be found i n n at http://tinyurl.com/64dvmu5 . This i a r comprehensive guide is designed to pro- T e v vide a logical diagnostic flow and help i t o the technician avoid overlooking poten- m o t tial issues, which from Ford’s perspective A u will ensure that thevehicle is repaired ef- y s e t ficientlyand correctly thefirst time. r u Technicians using this guide will lo- o c cate the root cause, but they may not o t o understand why they’re performing the h P steps listed. One example is step 2: This is what can happen when a customer skips preventive maintenance. Oil “Check Engine Oil Level – Check for sludge builds up and can damage the reservoir filter screen. Once the screen is contaminants (fuel, coolant), Correct compromised, debris can enter the high-pressure pump. Grade/Viscosity, M iles/Hours on oil, correct level.” Engine oil quality and The oil travels from the oil cooler to removed, allowing the oil to drain back level are critical for correct operation of the oil filter, and any pressure greater into the pan; the other is an antidrainthe fuel injectors and a common cause than 20 psi bypasses the oil filter and back valve that uses a one-way check of hard-start/no-start issues. Why is the travels to the high-pressure reservoir. valve to keep oil in the housing with the engine oil so critical? The oil filter housing contains two criti- engine off and the filter installed. This Fig. 1 on page 38 shows a simple oil cal valves: One is an oil change drain ensures that oil is available on initial flow schematic for the 6.0L diesel en- valve that opens when the oil filter is start-ups. gine. In order for the fuel injectors to The oil travels to the high-pressure operate, a minimum of 500 psi oil presreservoir, where approximately 1 quart of sure is required for start-up. The highoil is stored. The high-pressure oil pump pressure oil pump can deliver up to draws oil from the reservoir through a 33600 psi, but only if the low-pressure oil in. screen designed to catch debris. The system delivers the oil to the high-presphoto above shows what can happen sure pump. when preventive maintenance is neglectUnderstanding the low-pressure and ed. Keep in mind that oncethis screen is high-pressure oil systems is critical for damaged, debris will enter the highdiagnosing hard-start/no-start problems, pressure pump and be carried through so let’s take a closer look at these systhehigh-pressuresystem. temsin detail. The high-pressure oil pump is driven The low-pressure oil system begins by the camshaft and produces the highwith the oil pump drawing oil from the pressure oil needed to properly operate oil pan. Oil pressure in excess of 70 psi the fuel injectors. The pump is capable between the pump and oil cooler is of producing more volume and pressure vented back to the oil pan. than is needed for normal operation, The oil travels from the oil pump to and the excess volume is controlled by the oil cooler and any pressure greater the powertrain control module (PCM). than 25 psi is diverted around the oil Next in line is the injection control cooler to the oil filter. The benefit is propressure (I CP) sensor, which measures viding an alternative oil flow path during the oil pressure leaving the pump and high oil flow conditions. reports this to the PCM. The PCM uses
Understanding the low- and high-pressure oil systems is critical for diagnosing hard-start/nostart problems.
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FORD POWER STROKE DIESEL NO-START DIAGNOSIS
Here are two examples of where oil pressure may be lost in the high-pressure system. Injection pressure regulator (IPR) damage (left photo) and O-ring issues (right) are very common causes of hard-start and no-start complaints.
the information from the ICP sensor to regulate the oil pressure using the injection pressure regulator (I PR). This is a duty-cycle-controlled solenoid that opens and closes to achieve the desired oil pressure. The IPR duty cycle for a normal hot idle engine is approximately 30%. In order to maintain the correct oil pressure, excess oil is diverted back to the oil pan. During engine start-up, the PCM needsto see at least 500 psi. I f the pressure is too low, the PCM increases the duty cycle percentage; in other words, it closes the IPR, creating a restriction to increase the oil pressure. I f the PCM command reaches85%, the IPR is fully closed, which indicates a major problem in the oil supply chain. The photo above left shows a damaged IPR where the debris catch screen is almost completely gone. I PRs are common failure items and will normally point to additional problems. F or example, if you find the high-pressure oil reservoir screen is damaged, then the IPR will likely have debris present, and if the I PR screen is damaged or
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clogged, the high-pressure oil reservoir screen is likely damaged as well. After leaving the high-pressure oil pump, the oil travels through a series of branch tubes, standpipes, passages,
During engine start-up, the PCM must see at least 500 psi. If the pressure is too low, the PCM closes the IPR.
high-pressure oil rails and finally the fuel injectors. Keep in mind that these connection points will have O-rings sealing the system. F ig. 1 cannot properly demonstrate all the possibilities, but if you look at where the lines connect to the components described, each point would likely have an O-ring. O-rings should never be reused under any circumstance. We’ll discuss how to check for leaks later in the article. Steps 1 through 6 in the “Ford Hard Start/No Start Diagnostic Guide” deal with visual inspection, engine oil quality, intake/exhaust restrictions, fuel quality and fuel pump pressure and volume. Steps 7through 9cover checking for diagnostic trouble codes (DTCs) and performingKOEO tests. Experienced technicianswill check for DTCs first. If the following DTCs are present—P1378, Fuel I njection Control Module (FI CM ) voltage circuit low; P0611, FICM Internal Failure; P0261, P0264, P0267, P0270, P0273, P0276, P0279 and P0282, All Fuel I njector Circuits are low; and/or U0105, Lost communication with FICM—the most likely
FORD POWER STROKE DIESEL NO-START DIAGNOSIS cause will be a faulty FICM. Powers, grounds and connections between the FICM and PCM should bechecked prior to replacement of theFICM. In caseswhere the FICM connections test okay, it’s always agood idea to check for newer PCM/FICM calibrations. It’s not uncommon to find TSBs where the onlyfixisupdatingthecontroller software.
The two screen captures in Fig. 2 show the parameters that should be monitored while cranking the engine. Keep in mind that if the battery voltage drops below 9.5 volts, the scan tool might reset. If this occurs, correct the battery issue before continuing. In this example, Engine Oil Temperature (EOT) is included but is not aparameter that needs to be monitored while cranking. The initial note on the Diagnostic Guide is checking EOT. I f it’s below 60°F and the vehicle will not start, and the recommendation is to check the Glow Plug System Operation first. A – V PWR. Module Voltage B – FICMLPWR. FICM Logic Power C – FICMVPWR. FICM Vehicle Power. The Guide specifies 8 volts minimum for all three (A, B and C), but above 9.5 is a real-world value. I f the voltage values are below the recommended specification, this should be corrected first. D – RPM. The form states 100 rpm minimum, but a real-world value is above 120rpm. Low rpm can be caused by electrical issues. If the value is 0, check the crankshaft position sensor (CKP). E – I CP. ICP Pressure. A minimumof 500 psi is required for injector operation. As detailed earlier, there are many possible causes for low ICP pressure. The possible causes could be located in the low-pressureor high-pressuresection. F – I CP V. ICP Voltage. Minimum voltage is specified as .80 volt while cranking. Zero volts might indicate wiring or connector issues. G – Fuel PW. Injector pulse width defaults to 0 without a CKP signal. Range 500µS to 2mS. H – F ICMSYNC. No sync from the FI CM could be caused by camshaft position sensor (CMP) or CKP faults. The value should be YES after 120 rpm is reached. The Diagnostic Guide does not referenceIPR % =Inj Press Reg, but thisis a Fig. 2 These screen captures show the critical parameters that should be critical parameter for checking the state of oil system health. As discussed earlier, watched while cranking the engine. The capture on the top is from a knowngood vehicle, while the one above is from a defective vehicle. IPR should be approximately 30% idling
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I f no DTCs are present or if the DTCs do not relate to a no-start condition, continue to step 10, Scan Tool – Data List Monitoring. This is the step where you really get to see what’s happening with the engine management system. It lists eight specific parameters that should be monitored while cranking the engine.
FORD POWER STROKE DIESEL NO-START DIAGNOSIS hot. If the value is higher or has reached 85%, there’s an issue with the oil system, and it’s only a matter of time before a hard-start or no-start issue develops. If you service vehicles equipped with this
shows the vehicle running after warm restart with the ICP pressure high. But the pressure will continue to lower to the desired level. The Inj Press Reg percentage will continue to decrease until the ICP desired pressure is reached. The screen capture on the bottom shows that the vehicle will not start. The voltage values are normal, rpm is greater than 120, sync fromtheFICM is normal. The ICP is below 500 psi and the I nj Press Reg has reached 85%, which means there’s an issue in the oil system. F ig. 3 graphically displays two vehicles while cranking. The recording at the top showsa vehicle that will not start. The red vertical lines relate to the values below the graph. I n this case rpm is good but ICP is not capable of reaching 500 psi and the IPR is fully closed. The bottom recording shows a vehicle that’s operating properly. The timeline shows that it takes less than 4 seconds to start and stabilize the injection control pressure. By now you should start to see atrend. After a quick glance at the other parameters, the primary focus should be the ICP and the IPR percentage. If the ICP is unable to reach 500 psi, you need to determine why. Step 1: Check the lowside oil pump pressure. Also, pay close attention to the oil filter and related check valves. Step 2: Using a scan tool with IPR bidirectional conFig. 3 These are graphical examples of how the ICP, IPR and rpm work together. The screen trol, openand close theIPR to see if anypressure change capture on top is from a known-bad vehicle that will not start, which had an oil pressure leak; the screen capture above is from a known-good vehicle. occurs. If nothing hap-
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engine on a regular basis, it’s not a bad idea to check these values. Now let’s take a closer look at the two scan tool examples. In Fig. 2 on page 42, the screen capture on the top
FORD POWER STROKE DIESEL NO-START DIAGNOSIS pens, the IPR will need to be checked. Step 3: The photo below shows an adapter used to check for leaks at the ICP port. The ICP is removed and the adapter/air hose are installed. The shop air pushes the oil out of the high-
pressure system through the I PR into the oil pan. Once you hear the air flowing easily, use a scan tool to command the IPR to 85%, which closes off the high-pressure system. If the airflow doesnot decrease, check the IPR. Now
Here are two test devices for diagnosing a no-start condition on a Ford 6.0L Power Stroke diesel engine you cannot live without. The adapter with hose attached (top photo) is used to check for high-pressure leaks at the ICP. The two block-off tools above check the high-pressure pump’s deadhead pressure.
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use a stethoscope and listen for leaks. Step 4: If no leaks are found, use the high-pressure deadhead isolation tools to determine if the high-pressure pump can produce sufficient pressure. Follow the manufacturer’s recommendations for the proper test sequence. The pump should be able to produce 1500 psi while cranking and IPR over 60%. One quick check to determine if ICP is above 500 psi and the vehicle will not start is to verify that the ICP is accurate. Simply disconnect the IPR; if the vehicle starts, the ICP is out of calibration and should be replaced. I f vehicle does not start, continue with other non-oil-related issues. I f you skipped Steps 4 through 6 on the “Hard Start/No Start Diagnostic Guide,” now would be a good time to review the fuelrelated items. Check fuel quality, electric fuel pump pressure and fuel pump inlet restriction. Keep in mind that one bad injector will not create a no-start, so if the oil-related systems test good, the likely causeis fuel-related. Unfortunately, we cannot cover all possible causes and test sequences in detail here, so it’s important to follow all manufacturer recommendations. As for the 6.4L diesel engine, one critical difference between it and the 6.0 is that the 6.4L engine does not use a high-pressure oil system for fuel injector operation. It usesa high-pressure pump, but it’s pressurizing diesel fuel, not oil. If you decided to connect a scan tool looking for I CP, IPR or FICMSYNC, you won’t find these parameters. You’ll be monitoring parameters like pressure control valve, volume control valve and fuel rail pressure sensor. In order to be accurate and efficient when diagnosing Ford’s 6.0L diesel, you need to understand the systemyou’re diagnosing. The most successful driveability technicians do not rely on troubleshooting tips; they use a logical process based on how the systemfunctions. This article can be found online at www.motormagazine.com .
