Engine/Transmission (1994 - 1998) Fuel leak @ fuel htr wires

[RWorth]

This has probably been discussed before. I know that Cooker gave the part numbers to replace the the fuel heater and the wire harness. When starting my truck yesterday I notice, once again, that it took more than a few turns of the starter before the motor fired. Well I began to look for a fuel leak. Things that I replaced last month, return and supply fuel lines, the new WAIF valve I installed in July was causing loss of prime so I replaced it again and seems to be holding. I noticed the pumpkin on the front axle was damp and I found fuel on the connector on the fuel heater. I notice about three months ago the temp sensor and wiring were melted to the point that one wire was burnt into, also the heater measures infinite resistance on the Fluke 87. I have the part numbers for the sensor wire harness and the fuel heater. When replacing these parts will this also take care of the fuel leak? Also will this leak cause the engine not to fire on the first bump of the starter?



Thanks for your time.

 

[Joe G.]

There are a couple of suspects to check.



The lift pump has a manual pump button with a boot over it. If it's leaking there will be fuel there. It's a pretty easy fix. I spent 51 cents for a new O ring. Take the boot off and you will see how to get it out. The stock O ring is kind of oval in the shape of the edge. An ordinary round one has been working fine for me for over 50K miles.



The other suspect is the return manifold connection to the top of the fuel filter. The manifold is the tube assembly that collects return fuel from the injectors. It goes to the rear of the engine and across to the top of the fuel filter. The connection to the filter is a double banjo fitting, one tube is the return manifold and the other is the fuel supply line. The washers in the fitting may be leaking. There are four of them, two small and two large. The two small ones leaked for me.

 

[Cooker]

RWorth,



I received your email yesterday. I will have time to respond tomorrow.



-Ryan

 

[RWorth]

Joe,

The leak on the ruel return manifold and the fuel supply banjo fitting, was this leaking on top of the fuel filter and allowing diesel to puddle up? If this is the case then I don't have a leak in this area. If it was leaking there then, if I understand correctly the

o- rings that you replaced are in the banjo fitting. Would that be correct?

 

[Joe G.]

The O ring I mentioned is in the manual pump part of the lift pump.



The banjo fitting has flat washers. Mine never had fuel puddle up. It just seeped a little and ran down the side of the engine to the lift pump where it dripped a little. It was not a very big leak on mine. It probably would have developed into a big leak, but I look around for suspicious stuff when I service the truck. I saw the slight fuel leak that appeared to be at the lift pump. It took a little time to actually locate the real leak point. If it is leaking it will be damp at the banjo fitting. I cleaned mine with brake cleaner. When I ran the engine it got damp again. No flood of course, just a seep.



When the lift pump manual prime button O ring leaked it was a pretty good leak. It did a pretty good job of rust proofing the bottom of the truck.



These are places to check for a leak that gets the lift pump wet.



Replacing the fuel heater may take care of it ok, but if I were you I would track down the leak location for sure before spending any money.

 

[Blakers]

If the lift pump manual button o-ring is leaking, will the fuel be coming from under the rubber boot?



Both my 95 and my cousin's 97 have slight leaks that we cannot yet locate. Mine's dry around the lift pump button, but the banjo washers will be my next suspect place to look.



Will be changing hoses soon as one is old, but they aren't leaking.



Blake

 

[Joe G.]

When my manual push button leaked the push button was pretty wet. But, when mine leaked it didn't mess around.



Sometimes a slight fuel leak is a real bear to find. Brake cleaner, air hose, and a mirror are needed for the sneaky ones. When my WIF sensor/drain valve leaked it dripped a little bit from the drain hose so everything looked good except for the wet places where the fuel was blown.

 

[illflem]

Clean everything well then spray the suspect areas with aerosol athletes foot powder. Makes it easy to find the source plus prevents jock itch.

 

[Cooker]

JMHO, but if you fuel heater wires have melted, I would strongly suspect the fuel heater itself.

 

[RWorth]

Cooker,

When your fuel heater connector was leaking did it cause the time to start a little longer or was starting the same, as in bump the starter and the motor fires?



Smae question to you Joe on the banjo fitting washers and the hand primer o-ring?



TIA

 

[Cooker]

Yes.



Anytime there is a fuel leak, you have to potential to loose a little prime making it start harder.

 

[Joe G.]

What Cooker said.

 

[RWorth]

Cooker, Joe, IllFlem and Others.



Thanks for replying and sharing your knowledge. Another reason this is the best site.



Roger