Engine/Transmission (1994 - 1998) Fuel Leak

[WDaniels]

Got to work this morning and noticed a real bad diesel smell. Opened the hood and had a fuel vapour coming up out of the engine compartment. Took it into the garage after work and it was wet from fuel from the front differential to the rear axle. Wiped everything down and ran it for about 20 minutes. Nothing. No leaks or anything. Was thinking that it was the fuel line from the injector pump but did that one last summer and after inspecting it, it was clean. Then a friend told me that the lift pump can leak out of the electrical connection. Did a search and have seen where several others had the same problem. What they didn't answer is can you reseal or replace the connection without replacing the entire lift pump? Or do I have to replace the pump. Any help is appreciated.

WD

 

[Joe G.]

The electrical connection is in the fuel heater part of the heater/pre-filter assembly. It's not part of the lift pump in spite of being fastened to the block with the same screws. It's really simple to remove. You need a 17mm socket, a u-joint, and extension to get the pre-filter off from the bottom. Then an 8mm allen wrench will remove the adapter screw from the black plastic hockey puck looking thing that is the fuel heater. Unplug the electrical connection. Then, using one of the two gaskets, put the pre-filter back in place of the fuel heater. Throw the fuel heater away. It's absolutely worthless even when it works.

 

[WDaniels]

That is the first time I've ever heard that the fuel heater is useless. Does it not preheat the fuel? Or at least remove ice crystals from the fuel? Are the two gaskets exactly alike? Thanks for the education.

WD

 

[Joe G.]

The gaskets are exactly alike on my '95. They probably are on your '97 as well, but check to make sure.



There is about a quart of cold fuel between the fuel heater and the injectors. There is no way to get heated fuel to the injection pump before your battery runs down when you start. Other applications of the 5. 9 Cummins don't have a fuel heater that I have ever heard of. After the engine starts then it's creating a lot more heat than the fuel heater. It's just a failure waiting to happen. I have discussed this situation on other threads. If someone finds a situation where the thing is actually doing something useful I would like to know about it.

 

[WDaniels]

Thanks for the education Joe.

WD