Engine/Transmission (1994 - 1998) Fuel Leak at lift pump

[onstottc]

Driving back from Cali I noticed a fuel leak. About 10 drops a minute with the engine running. I decided to check it out tonight. I have good fuel pressure 20-30 psi. I removed the fuel heater and it still leaks. I was able to see fuel dripping off of the bottom of the lift pump. The top of the lift pump is not as soaked with fuel as I would think it would be it the fuel was coming from a leak above it. I cant tell where it originates. Is there a weep hole in the lift pump? Any suggestions where the leak can be?

 

[Joe G.]

It's most likely the O-ring for the push botton. Easy and cheap fix if it is. Remove the rubber button cover. Unscrew the plastic push button. There is a O-ring around it about 1" in diameter. You can get a replacement at NAPA for about 50 cents.

 

[onstottc]

The pump seems pretty dry around the area of the primer. . I think the leak is coming from an area south of that...

 

[Joe G.]

Another place to check is the input fitting to the fuel filter. It is a stacked banjo fitting where fuel from the lift pump and from the return pipe from the injectors combine. If it leaks here fuel will run down the fuel line to the pump and drip off the bottom of it.

 

[onstottc]

Thanks... It looks dry on all of the lines going from the filter to the pump.

 

[DonFitzwater]

lift pump leaks

There is a weep hole in the bottom of the pump. I found this out when I changed mine recently. It is close to the flange near the bolt head, but I don't remember which side of the pump it is on. Fortunately this hole keeps a failed lift pump from filling the crankcase with fuel and wiping out an engine as best as I can tell.

 

[Joe G.]

It might be a good idea to use some brake cleaner and air to get everything clean. Then put a few pieces of masking tape in a few places. They will show wet if there is a leak above them where you might not notice it otherwise. Then get under it while it's running and watch for the leak.