Fuel pump replacement help
#1
08-24-2010, 10:47 PM
Fuel pump replacement help
I have a 1996 6.5l TD, I have searched this forum and haven't found much help, but then again I might have missed a thread so I apologize if I did. But now my question:
Where is the fuel pump located, and is there anything I need to know before changing it or installing the new one?
Where is the fuel pump located, and is there anything I need to know before changing it or installing the new one?
#2
08-24-2010, 11:02 PM
l System Driver - FSD
Buy Remote FSD Kit
Diesel Trouble Shooting
© Copyright 2004 - 2007 Chuck Kopelson 04/22/2003
Updated December 2, 2007
If this site has helped you consider a Donation. Donation Info
Note: The FSD/ PMD (same thing) is a small black box on the side of your injection pump. It is a signal amplifier that powers the fuel solenoid on your injection pump. It has 2 transistors mounted on it's backside that generate heat that has to be dissipated. In it's stock location it can over-heat and fail.
The story usually begins like this. You’re driving along and the engine just quits. You lose your power steering and the truck is very hard to steer. You pull over to the side of the road and you are able to restart. After a few days the stalls become more frequent and the truck will be hard to start. You realize that you can’t trust the truck and something has to be done. This is the classic symptom of a failing Fuel Solenoid Driver (FSD) also known as a Pump Mounted Driver (PMD). This is an electronic switch that controls the fuel flow on a Stanadyne DS-4 electronic injection pump. Electronic injection pumps are used on all Hummers with the GM 6.5 turbo diesel between 1996 and 2004. A failed FSD will not display an engine light. Pictured above the FSD is a small black box about the size of a deck of cards bolted to the side of your injection pump. It is an amplifier that receives signals from the engine computer to pulse the fuel solenoid which tells the injection pump to send fuel to the engine. It has 2 power transistors mounted on the back that generate heat that has to be dissipated. The injector pump is mounted deep in the center valley of the engine in a very hot environment. The FSD is exposed to heat that can cause it to fail over time.
The Stanadyne DS-4 pump has been used on GM trucks since 1994. Owners of older Chevy and GMC trucks and G-Vans have experienced these problems years before Hummer owners have. GM had so much trouble with early generation electronic injector pumps that they had to warranty the units for 100,000 miles. When AM General purchased these motors from GM they did not get a 100,000 mile warranty. In 1999 AM General bought the plant and took over production of the 6.5 engines later that year.
Heat generated by the FSD is supposed to be carried off by the diesel fuel flowing through the pump. While this is true, the damage is being caused right after the engine is shut down. After you stop the engine the fuel of course stops flowing and the water pump stops circulating coolant which in turn causes the engine temperature to actually spike for a short time. This is called heat soak. This rise in temperature heats the FSD which is bolted to the injection pump sitting on top of the engine. The continual heating and cooling cycles cause the FSD to fail over time.
There have been 3 variants of FSD's. FSD's with a 30214 on the case are the worst. This is the first generation and the most prone to fail. FSD's with a 34264 are second generation, and are preferred by some Stanadyne repairmen because they will either work, or won't work, like "a light bulb". The third generation number 34583 was designed to allow you to "limp home" by operating for a short while and then fail.
Because the injection pump is deep in the valley of the engine the FSD mounting screws are almost impossible to get at unless you remove the manifold (which is a major job. I've spoken to a couple of mechanics that were able to get the FSD out by using a very short torx bit wrench but I can't see how it was done.
If your FSD needs replacing it seems unwise to put it back where it was, down in the heat. Why not save all the trouble and labor and simply mount the FSD on a heatsink somewhere away from the engine where it can stay cool.
There are a number of aftermarket products that have specially designed heat sinks and extension cables that let you remote mount your FSD in a cooler spot. The kit used in this article is from Flash Off-Road. This solves the problem once and for all.
FSD’s have a calibration resistor pack that describes the pump to the electronic control system. Because there is variability in the manufacturing of injector pumps the resistor is used to calibrate the engine computer to the pump. The resistor pack is a small circuit board with a resistor that is inserted deep into the FSD’s socket. New FSD’s don’t come with resistors.
The #5 calibration resistor is considered the "average", and almost any pump will work with a #5 resistor. The resistor is only used when the control computer forgets what the value is, which occurs after the batteries are disconnected or a hard reset is performed with a tech tool. If you don't use a resistor you will get a p1218 error code when the computer tries to read the value. Your truck will still run.
Whenever I run into a failed FSD I always replace it with a remote mounted unit on a heatsink and just abandon the defective FSD on the injection pump.
There are sevral articles at www.flashoffroad.com along with pictures. See if any of those help.
Buy Remote FSD Kit
Diesel Trouble Shooting
© Copyright 2004 - 2007 Chuck Kopelson 04/22/2003
Updated December 2, 2007
If this site has helped you consider a Donation. Donation Info
Note: The FSD/ PMD (same thing) is a small black box on the side of your injection pump. It is a signal amplifier that powers the fuel solenoid on your injection pump. It has 2 transistors mounted on it's backside that generate heat that has to be dissipated. In it's stock location it can over-heat and fail.
The story usually begins like this. You’re driving along and the engine just quits. You lose your power steering and the truck is very hard to steer. You pull over to the side of the road and you are able to restart. After a few days the stalls become more frequent and the truck will be hard to start. You realize that you can’t trust the truck and something has to be done. This is the classic symptom of a failing Fuel Solenoid Driver (FSD) also known as a Pump Mounted Driver (PMD). This is an electronic switch that controls the fuel flow on a Stanadyne DS-4 electronic injection pump. Electronic injection pumps are used on all Hummers with the GM 6.5 turbo diesel between 1996 and 2004. A failed FSD will not display an engine light. Pictured above the FSD is a small black box about the size of a deck of cards bolted to the side of your injection pump. It is an amplifier that receives signals from the engine computer to pulse the fuel solenoid which tells the injection pump to send fuel to the engine. It has 2 power transistors mounted on the back that generate heat that has to be dissipated. The injector pump is mounted deep in the center valley of the engine in a very hot environment. The FSD is exposed to heat that can cause it to fail over time.
The Stanadyne DS-4 pump has been used on GM trucks since 1994. Owners of older Chevy and GMC trucks and G-Vans have experienced these problems years before Hummer owners have. GM had so much trouble with early generation electronic injector pumps that they had to warranty the units for 100,000 miles. When AM General purchased these motors from GM they did not get a 100,000 mile warranty. In 1999 AM General bought the plant and took over production of the 6.5 engines later that year.
Heat generated by the FSD is supposed to be carried off by the diesel fuel flowing through the pump. While this is true, the damage is being caused right after the engine is shut down. After you stop the engine the fuel of course stops flowing and the water pump stops circulating coolant which in turn causes the engine temperature to actually spike for a short time. This is called heat soak. This rise in temperature heats the FSD which is bolted to the injection pump sitting on top of the engine. The continual heating and cooling cycles cause the FSD to fail over time.
There have been 3 variants of FSD's. FSD's with a 30214 on the case are the worst. This is the first generation and the most prone to fail. FSD's with a 34264 are second generation, and are preferred by some Stanadyne repairmen because they will either work, or won't work, like "a light bulb". The third generation number 34583 was designed to allow you to "limp home" by operating for a short while and then fail.
Because the injection pump is deep in the valley of the engine the FSD mounting screws are almost impossible to get at unless you remove the manifold (which is a major job. I've spoken to a couple of mechanics that were able to get the FSD out by using a very short torx bit wrench but I can't see how it was done.
If your FSD needs replacing it seems unwise to put it back where it was, down in the heat. Why not save all the trouble and labor and simply mount the FSD on a heatsink somewhere away from the engine where it can stay cool.
There are a number of aftermarket products that have specially designed heat sinks and extension cables that let you remote mount your FSD in a cooler spot. The kit used in this article is from Flash Off-Road. This solves the problem once and for all.
FSD’s have a calibration resistor pack that describes the pump to the electronic control system. Because there is variability in the manufacturing of injector pumps the resistor is used to calibrate the engine computer to the pump. The resistor pack is a small circuit board with a resistor that is inserted deep into the FSD’s socket. New FSD’s don’t come with resistors.
The #5 calibration resistor is considered the "average", and almost any pump will work with a #5 resistor. The resistor is only used when the control computer forgets what the value is, which occurs after the batteries are disconnected or a hard reset is performed with a tech tool. If you don't use a resistor you will get a p1218 error code when the computer tries to read the value. Your truck will still run.
Whenever I run into a failed FSD I always replace it with a remote mounted unit on a heatsink and just abandon the defective FSD on the injection pump.
There are sevral articles at www.flashoffroad.com along with pictures. See if any of those help.
#5
09-11-2010, 08:57 AM
The fuel pump was under the hood in my hummer, I have a 96 t-Diesel, it took my employee only about 20 minutes to repalce
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