Frequently Asked Questions

As a rule of thumb, there are three things that effect starting of a diesel engine.  One is cranking speed.  Commonly, a diesel engine needs to crank at approximately 200 RPM to start properly.  Things to check are:  the condition of your batteries, the battery cables and the starter.  

The second is compression.  Diesel engines rely on the heat generated from compressing the air in the combustion chamber to ignite the fuel.  If the compression is low, the heat is low as well.  An engine which uses glow plugs to start when the engine is cold may experience a hard-start condition when the engine is warm if the compression is low.

Third is the condition of the fuel system.  If the fuel pump is weak or the conditions of the injectors are poor, the engine may be hard to start.  On some fuel systems, hard-starting may be the first sign of a fuel pump that is failing.  If the fuel tank is located lower than the fuel injection pump, a leak in the fuel system may allow the fuel to drain back to the tank when the engine sets for several hours.

The 7.3L, and 6.0L Ford Powerstroke uses a HEUI system (Hydraulic Electronic Unit Injector).  This system is a combination of hydraulics, pressure regulators, sensors and relays.  Hard starting, no start, blue/white exhaust smoke and rough running are signs that your engine needs to be serviced by a qualified technician.  

In short, if your engine and starting system are in good condition, you need to call on us to put your fuel system back in good order again.

The electric fuel supply pump tends to be a common item to fail on the 1998 1/2 through 2002 Dodges.  These trucks are equipped with a Bosch VP44 fuel injection pump.  The Bosch VP44 fuel pump needs to be fed by a positive fuel pressure from an electric fuel supply pump.  The Bosch fuel pump will draw fuel from the tank in the absence of being fed, however this causes the pump to operate in a negative pressure.  Operating with a negative pressure causes cavitations in the Bosch VP44 injection pump which results in a premature failure.  We recommend checking the fuel supply pump pressure periodically and or installing a low fuel pressure warning light.

HPCR is an abbreviation for High Pressure Common Rail.  In this type of fuel system a gear driven piston pump delivers high pressure fuel to a rail that is common to all the injectors in the engine.  The fuel pressure is typically around 5000 psi at idle and can reach 26000 psi at wide open throttle under full load.  The ECM decides which injector it is going to turn on and for how long it will be turned on.  With the high pressure fuel in the common rail, the ECM only has to activate each individual injector and the fuel is sprayed into the cylinder and compressed and burned.  As always it is never a good practice to replace parts without proper diagnosis and these complex systems cannot be diagnosed over the phone or without the use of a scan tool.  Beware of budget code readers, these scan tools only read generic OBD II codes and cannot perform diagnostic tests.  (THEY WILL NOT HELP YOU DIAGNOSE YOUR VEHICLE)

Some typical problems associated with the HPCR system on the 2003-2007 Dodge pickups could include hard starting (extended cranking time until it starts), starting and stalling repeatedly, and low power or light blue or white smoke out the exhaust.  A hard start with extended cranking times is usually due to the fuel system being unable to achieve a high enough rail pressure for the engine to start.  This can be caused by one or more of the injectors failing and allow the fuel rail pressure to be bled off and a hard start to occur. Another source could be the FCA (fuel control actuator on the CP3 high pressure pump) to become stuck in a closed position.  This FCA can also fail in a manner that would cause surging at idle.  Intermittent stalling can be caused by the fuel supply pump failing on the 2003-2004.5 model year trucks.  Low power and light blue or white smoke at idle can be an indication that one or more injectors have begun to fail.

Failure of the fuel supply pump or low fuel pressure is often not noticed in the drivability of the truck. Often the first symptom is what is referred to as "dead pedal syndrome" or no response when the accelerator pedal is depressed. Generally by the time symptoms are noticed damage has already been done to the Bosch VP44 fuel injection pump. The low fuel pressure warning light is a good investment.

Yes, there are replacement electric fuel pumps that can be installed.  The 2004 1/2 Dodge comes with a fuel supply pump that is mounted in the fuel tank.  Chrysler is offering this, in tank fuel pump kit, as a retro fit for the earlier trucks.  We recommend the FASS pumps made by Diesel Performance Products (DPP)  These pumps are heavy duty and supply more than adequate the amount of fuel that is required, even for serious performance upgrades.  They are backed by a LIFETIME warranty and are rebuildable.  The Dodge application is the most common, but FASS also offers fuel supply pumps for the GM Duramax, and Ford Powerstroke as well as many other applications.

From 1982-93 both Ford and General Motors used a fuel injection pump made by Stanadyne.  Stanadyne controlled the advance of the timing by applying primary fuel pressure to an advance piston which rotated a cam ring to advance the timing. 

This method works fairly well, but in time, approximately 100,000 miles, the advance piston will wear the bore in the housing where it rides and affects the timing in which fuel is delivered to your engine.  As your fuel pump ages, this wear comes on gradually and is probably unnoticed until, that is, it reaches the point where it causes your engine to puff out some light blue smoke. Prior to this you may experience a reduction in performance and fuel mileage.  There are other parts that wear in the pump as well, so when your pump reaches this point, it's time for an overhaul.

Injectors are one of the most critical parts of your fuel system, but often overlooked.  The injector nozzle determines how the fuel is mixed with the air in your combustion chamber.  You don't want to take any chances here.  We recommend that your injectors be checked and or replaced after 4000 hours or 150,000 miles.  Even though they may still be working good, tests made by large trucking fleets have proven that changing injectors is good preventative maintenance that avoids costly down time, extends engine life and assures good fuel economy.

General Motors used a Stanadyne DS fuel injection pump on the 1994-1999 6.5L diesel engines.  The DS pump is computer controlled by a device called a primary control module (PCM).  The PCM reads data sent to it from the encoder sensor located internally in the pump and a pump mounted driver (PMD) .  Either the PMD or encoder sensor may fail intermittently and cause the engine to stall.  You need to hook up a scan tool to read the fault codes stored in the computer to make a determination of the failure.  A trained technician is helpful here, there may be other conditions on the vehicle that can effect the operation of the fuel pump as well.  It may not be necessary to replace the fuel pump, some conditions may be remedied on the vehicle.

The typical pattern failures on the Duramax diesel engine include hard starting (extended cranking time until it starts), and low power or light blue or white smoke out the exhaust. A hard start with extended cranking times is usually due to the fuel system being unable to achieve a high enough rail pressure for the engine to start. This can be caused by one or more of the injectors failing or a weak CP3 high pressure pump. Another source could be the FCA (fuel control actuator on the CP3 high pressure pump) to become stuck in a closed position. This FCA can also fail in a manner that causes surging at idle. Low power and light blue or white smoke at idle can be an indication that one or more injectors have begun to fail. The reason for stalling or extremely low power is most likely a plugged fuel filter. Note: GM has superseded the fuel filter for the Duramax engine and the updated part has a stepped design that has a smaller diameter on the bottom portion of the filter cartridge.