Engine/Transmission (1994 - 1998) Leaking fuel while priming

[NKenny]

Truck is a '94 Auto. I bought the truck with a fuel filter reloction kit. The lines were all rubbed through so I just pulled the kit and replaced it with the filter in the stock position.



While trying to prime the truck with the new filter on, after about 5 pumps on the primer bulb, fuel began spitting out with each pump and no fuel was getting into the filter, much less to the cracked fuel lines. The truck has had some hard starting symptoms for the last 2 months while an employee was driving it. There doesn't appear to be any fuel leaking with the truck is sitting.



Question is... Is the fuel coming out a sign of a plugged pre-filter / fuel heater, cracked lift pump, or other? Is the overflow vavle a possibility for causing this?



Thanks.

 

[wcjp]

Where is the fuel leaking from? The fuel preheater assembly might not be screwed on tight. Did you prelube the fuel filter gasket? Is it leaking from lift pump? There are two orings inside that can be replaced. It's hard to say without more info.



Also, if it hasn't been done before, KDP, replace the fuel supply/return lines with marine style diesel fuel line. On my 96', the root problem was the fuel preheater/lift pump soft line. It was severly dryrot. Leaked lots air in, no fuel out.

 

[NKenny]

Its leaking right at the lift pump. My hand that was pumping the primer was getting full of diesel. Marine supply line is a good idea.

 

[JFaughn]

You need to find the leak , right at the lift pump is not a find , with the body of the pump cracking / very strange , you have at least 4 possibilities , the seals at the button for pumping , the in line , the out line & all that I have seen have a weep hole - to show that if its leaking into the block .
And with out looking close , it may be spraying from something els near by .

 

[NKenny]

More complete investigation to come...

 

[tgordon]

If the fuel is leaking from the lift/transfer pump that could also be the source of your hard start problem. It would allow air to go into the line there. Have seen this on many tractors and on those it was a simple $25 fix, but a little bit more on these trucks.