common rail electronic injection systems diesel driveability

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Common Rail Electronic Injection Systems

Diagnosing Diesel Driveability Issues, for guys who ‘Don’t

Do Diesels’.

• Needed:– Scanner

– Current probe/Amp Clamp

– Rag

– Oil checked



How diesel engines differ from gas engines:• Intake Stroke: Gas is Fuel and Air, Diesel is Air only• Compression Stroke: Gas is spark ignition, Diesel is

injected fuel only• Power Stroke: Gas is spark ignited, Diesel is compression

ignited• Exhaust Stroke: Gas and Diesel are the same• Diesel engines compress (which heats) air in the cylinder,

so when diesel fuel is injected it combusts. Where as gas engines need spark to detonate the gasoline.



How diesel engines differ from gas engines (cont’d):• Gas engine fuel systems are lower pressure, Diesel

engine fuel systems are high pressure• Diesel high pressure common rail (HPCR) system has an

extra pump (High Pressure Pump) not found on most gas systems



2003 – 2008 Dodge 5.9 Cummins HPCR• Lift/Supply Pump

– 03-04 has external pump, fuel filter, suction between lift pump and tank, supplies 8-12 PSI fuel to high pressure fuel pump

– 05 the pump was moved into the tank, TSB update for older models but old external pump is still available through supplier

– Pump is 100% on with key and runs 4 amps

• High Pressure Pump– Engine driven hydraulic unit located on the left side of the block

– Not timed to engine

– Provides high fuel pressure to the common fuel rail

– Fuel pressure range is 5,000-23,000 PSI, needs to be 5000 PSI minimum to start



2003 – 2008 Dodge 5.9 Cummins HPCR (cont’d)• Electronic Fuel Control Solenoid

– 2 wire solenoid controlled by ECM, signal return and PWM signal (pulsed power)

– Lets low pressure fuel (8-12 psi) supply in which controls the high pressure, more fuel in = more pressure

– Fuel control actuator (FCA) is normally open and is 35% at idle pulsed power

– For max fuel – unplug it

• Common Rail– Rail/Accumulator, high pressure fuel inlet, rail pressure sensor, pressure

limiter/regulator valve (safety valve), fuel tank return, injector line



2003 – 2008 Dodge 5.9 Cummins HPCR (cont’d)• Connector Tubes

– Between the injector lines and the injectors– Flange nut loosens then tube leaks at the injector, leaking fuel goes into ‘rifle

passage’ through head and out back of head– Connector Tubes are high failure items – Note: Tube to injector is a ‘press’ fit created by the pressure of the flange nut

pushing the tube against the injector. If the nut loosens the spray of high pressure fuel at the end of the tube may damage the tube seating surface on the injector. Therefore, simply tightening the flange nut may not stop the leak.

• Injectors– Electrically operated and controlled by 2 wires to the ECM– 90 volts, 20 amps– Pilot injection, Main injection– Can test with current clamp



2003 – 2008 Dodge 5.9 Cummins Exercise

• Complaint: No Start, Hard Start, Extended Crank, Low Power– Using scan tool, look at Engine (ECM) data

– This vehicle:

» RPM = 251

» Fuel Pressure (PSI) = 1351

» Fuel Pressure (V) = 0.6

– Low Pressure check:



2003 – 2008 Dodge 5.9 Cummins Exercise (Cont’d)• Fuel Rail Pressure Sensor Reference info:

– 0 psi = 0.4V

– 5000 psi = 1.2V

– Idle 5600-5700 psi = 1.35V

– Crank 7000 psi = 1.5V

– 10,000 psi = 2.2V

– 15,500 psi = 2.9V

– 18,000 psi = 3.3V

– 22,000 psi = 4.0V



2003 – 2008 Dodge 5.9 Cummins Exercise (Cont’d)• Again, this vehicle:

– 8-12 psi from the Lift/Supply Pump to the High Pressure Pump

– 1351 psi from the High Pressure Pump to the HPCR

» Fuel Pressure Too Low to Start. Should be 5000 psi minimum.

» Bad High Pressure Pump or a leak. Unplug fuel control actuator to enable max fuel.

• Remember the oil check? A leak at the injector tip into the cylinder will cause the oil to be over full. Fuel out the return at the fuel filter during crank means a leak at the connector tube.

• Using a Miller 9011 Tool, you can check cylinder by cylinder for injector leaks. Cummins tend to leak at cylinder #5 or #6.

• Reminder: Replace tube and injector at the same time!



2003 – 2008 Dodge 5.9 Cummins Exercise (Cont’d)• Connector Tube Installation:

– Tighten tubes to 37 ft/ib

– Tighten high pressure line to 22 ft/lb

• Final Check:– Using scan tool, look at Engine (ECM) data

– This Vehicle Now:

» RPM = 751

» Fuel Pressure (PSI) = 5563

» Fuel Pressure (V) = 1.28



2001 – 2008 GM Duramax 6.6 HPCR• LB7 – 2001 to 2004 VIN 1• LLY – 2004 to 2006 VIN 2• LBZ – 2006 to present VIN D• LMM – 2007 VIN 6

2001 – 2004 LB7 VIN 1• No Lift/Supply Pump

– Supply from tank– Conventional sending unit

• Fuel Injection Control Module (FICM)– Fuel goes from sending unit to FICM, provides cooling for FICM– Controls each injector directly, power and ground control



2001 – 2008 GM Duramax 6.6 HPCR (Cont’d)2001 – 2004 LB7 VIN 1 (Cont’d)• Fuel Injection Control Module (FICM) (Cont’d)

– Controls high and low side fuel– Pulsed in firing order– ECM tells FICM what to do

• Fuel Filter Assembly– Fuel goes from FICM to fuel filter housing– Manual prime pump

» Use when changing filter or run out of fuel» 30 times or until resistant» Bleed port

• Injection Pump– High pressure fuel pump



2001 – 2008 GM Duramax 6.6 HPCR (Cont’d)

2001 – 2004 LB7 VIN 1 (Cont’d)

• Injection Pump (Cont’d)– In the block ‘V’

– Gear to gear drive off cam, not timed

– Two Sides

» Supply side - pulls fuel from the tank, 2 – 10 inches vacuum

» High PSI side - pressure for injection, 5,000 – 23,000 psi

» Megapascal (MPa) to PSI• 1 MPa = 145 psi

• 1,500 psi (10 MPa) minimum needed to start

• 5,000 – 6,000 (30 -40 MPa) psi at idle (Fuel Rail Pressure Regulator



2001 – 2008 GM Duramax 6.6 HPCR (Cont’d)2001 – 2004 LB7 VIN 1 (Cont’d)• Fuel Rail Pressure Regulator (FRPR) Solenoid (Cont’d)

– 2 wire solenoid controlled by ECM is normally open and supplies high side of pump

– 5 to 95 percent control» High percentage = low pressure» Low percentage = high pressure

– Unplug at front of motor

• Return Line• Fuel Pressure Relief Valve

– Saftey valve – On LB7 it opens at approximately 23,000 psi, On LLY it opens at approximately 26,000 psi

– Can be source of low pressure problem



2001 – 2008 GM Duramax 6.6 HPCR (Cont’d)2001 – 2004 LB7 VIN 1 (Cont’d)• Fuel Rail Pressure Sensor

– 3 wire sensor – 5V, Ground, Signal– 150 to 200 psi at KOEO (but at crank is most important)– 1.1 to 1.4 MPa = 0.5 to 4.5 V

• Fuel Rail– High Pressure Common Rail (HPCR)– Open any line impacts all cylinders– Pressure always available

• Injectors– 2 wire, 93 Volt, 20 Amp– Newer ones need to be programmed



2001 – 2008 GM Duramax 6.6 Exercise

2001 – 2004 LB7 VIN 1


– This vehicle:

» Fuel Rail Pressure (FRP) = 580 psi (4 MPa)

» Test the fuel supply system• Port for vacuum guage on right front of engine ($130 tool), or test at fuel filter

housing, or break into supply line at left rear of engine and ‘tee’ in

• Suction from the tank

• 2 – 6 inches vacuum at idle

• 8 – 10 inches vacuum at acceleration



2001 – 2008 GM Duramax 6.6 (Cont’d)

2004 – 2006 LLY VIN 2 Differences• May not have a FICM

– To eliminate plugged tank or vacuum leak to high pressure pump use external fuel source to inlet

– Should see 5,000 – 26,000 psi out of injection pump

– Injectors are more external and are 48 volt



• 2003 – 2008 Ford 6.0 Power Stroke (HPOR)• Horizontal Fuel Conditioning Module (HFCM)

– Located on the left frame rail– Fuel pump, water separator, fuel heater (03-05), water in fuel sensor, 10

micron primary fuel filter, drain, recirculation valve– 50 to 60 PSI, low pressure will cause injector failures

• On-Engine (Secondary) Fuel Filter– Fine filter, pressure regulator, air bleed/water drain, fuel pressure service

port, inlet, return, 2 lines to cylinder heads

• GEN II Injectors– Fuel supplied toward bottom of injector from fuel rail in each head, 50 psi

fuel o-rings just above and below fuel inlet, fuel exits tip at 28,000 psi– Actuated by high pressure oil 500 – 4,000 psi, which enters at the top– 48 volt, 20 amp– 4 wires, 2 coils each – one open and one close



2003 – 2008 Ford 6.0 Power Stroke (HPOR) (Cont’d)• GEN II Injectors (Cont’d)

– Known to work loose, fuel leaks from body

• High Pressure Oil Rail– 500 to 4,000 psi actuate the injectors and is the main fuel control– Two rails, one per head– High pressure oil fed from pump through H.P. oil branch, stand pipe and

check valve

• High Pressure Oil Pump– Gear to gear driven pump located in rear of engine valley, not timed

• Fuel Injection Control Module (FICM)– Complete control of injectors– Located at left rear valve cover– Performs injector self test every key on cycle



2003 – 2008 Ford 6.0 Power Stroke (HPOR) (Cont’d)• Powertrain Controle Module (PCM)• Injection Pressure Regulator (IPR) Solenoid

– 2 wire solenoid, PCM controlled and regulates injection control pressure– 4,000 psi– Max duty cycle = Max psi

• Injection Control Pressure (ICP) Sensor– Provides feedback on high pressure oil psi, supply power and ground, can

unplug– 0 psi = 0.2V 2,000 psi = 2.6V– 600 psi = 1.0V 3,200 psi = 3.9V– 1,000 psi = 1.5V 4,000 psi = 4.5V – 1,500 psi = 2.1V– Note: Always double check voltage. PCM can substitute value for psi.



• 2003 – 2008 Ford 6.0 Power Stroke


– Vehicle should have:

» 50 – 60 psi supply from HFCM

» Minimum 500 psi (0.8 V) at HPOR to start, if not:• Leaks or bad pump

» Remember to check the oil? If it’s low, you probably have a leak

– #1 problem is low oil pressure

– To disassemble then air check system is MAJOR labor, removing cab is faster (45 minutes)



2003 – 2008 Dodge 5.9 Cummins Intake Air Heater System• 2 Intake air heaters

– No glow plugs

– Both are on at KOEO

– They toggle back and forth at KOER

– 60 – 80 amps each (120 – 160 amps total)

– Relays located on left front fender

Complaint: No Start, Hard Start, Extended Crank, Misfire• Should perform cold start check outside

– Use scan tool or current probe to check relays and heaters



2001 – 2008 GM Duramax 6.6 Glow Plug System• 2001 – 2004 LB7

– Glow plug tips are gold– 12V operation– 20 amps each (160 amps total)

• 2004 – 2006 LLY– Glow plug tips are silver– 4.7V operation (12V pulsed)– 110 amps for 2 seconds, then 30 amps– Measure at first key on, before duty cycle

Complaint: No Start, Hard Start, Extended Crank, Misfire• Should perform cold start check ouside

– Use scan tool to monitor glow plug data



2003 – 2008 Ford 6.0 Power Stroke Glow Plug System• Eight Glow plugs

– One per cylinder– 20 – 25 amps each (160 – 180 amps total)– Glow plug light is independent

• Glow plug control module (GPCM)– Can detect problem with each glow plug– Can shut down individual glow plug

Complaint: No Start, Hard Start, Extended Crank, Misfire• Should perform cold start check ouside

– Use scan tool and clear glow plug codes first– Use a current probe and/or a jumper wire with a 30 amp fuse from battery

positive to test individual glow plugs– Possible misfire due to no injector pulse, check CKP and CMP inputs

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