Engine/Transmission (1994 - 1998) Fuel leak

[JLC1]

Wondering if anyone is experienced a problem similar to me...



1997 Dodge only leaks fuel for about the first 8 to 10 gallons of a full tank. After that the fuel leak completely goes away. Leaves me scratching my head as to the source of the leak... Near as I can tell the top of the fuel module is dry, but lets just say that the undercarriage of the truck is rust protected with diesel. If it was a line, wouldn't it leak all the time... It doesn't affect my mileage so it must not be leaking when running down the road. If the tank is full and I park in the driveway, it leave a large spot of fuel, maybe 2-4 ft in diameter depending on how long it is parked. In the mean time, I've been trying to run in half empty, but that's tough to do with no fuel gauge, but that's another question... Any help would be much appreciated. Thanks.

 

[JGK]

About where does the puddle form? Under the tank? Near the transmission or under the engine? About where is the leading edge of the fuel coating on the undercarriage?



My first thought about loosing only the top 8 or 10 gallons when sitting is a small split or hole in the tank.



-Jay

 

[JLC1]

Where it forms depends on if the truck is sitting uphill or downhill. It never seems to puddle behind the tank, but it will drop anywhere from the tank to up along the front control arm mount if the truck is sitting downhill. If on level ground it will dump somewhere along the length of the tank. I'm kind of wondering the same thing since it doesn't do it when the tank has some fuel driven out of it.

 

[RHestand]

Short of dropping the tank, I think I would have someone put small amount of air pressure (5-10LBs in filler neck) while you squirt soapy water everywhere you can see under there.

Several years ago I repaired a metal tank that had cracked on the bottom side. I used a two part epoxy puddy repair kit that held fine for many years, and was still dry when I sold the car.

I don't know if it would work on plastic, but you might check it out.

Good Luck, Ray

 

[GAmes]

The module is not located on the highest part of the tank, the filler neck is. If your gauge doesn't work it sounds like you need to pull it anyway. It could be the large seal under the hold down ring or one of the smaller seals for the rollover valve or in/out lines. If you don't have a toolbox, hitch or tank in the bed it is fairly easy to lift the bed for a good look.

 

[JGK]

With the puddle moving depending on the angle of the truck when its parked seems to indicate the fuel is leaking out up high and following something, like a fuel line or wire, then dropping off at the low point.



I'm with the others, get access to the top of the tank. If the bed is empty, I'd go for lifting it. I've dropped my tank and watched a friend lift his bed. If you have a jack and some 2X4s for extensions, and some blocks of wood to secure it once its up, lifting the bed seems to be the easiest. Don't forget to disconnect the grounding strap at the front of the bed. Also, consider wedging a towel between the bumper and the body panel just under the tail lights before you lift it.



I bet you find it up on top somewhere.



-Jay

 

[GAmes]

If it turns out that the top of your module is bad I have one listed in the pay it forward section. The sender is so-so, but worked when I took it out. It is a prime candidate for bombing as per Joe George's article.



I won't be back in TX for about a month, but if you need it you are welcome to it.



Gary

 

[JLC1]

I went ahead and ordered some trident hose for the fuel lines and return lines. I'm going to pull the bed soon and try to get to the bottom of this. Hopefully it isn't a cracked tank.

 

[MHalloran]

Yeah, if you're going to remove the bed ( took mine off - 8 bolts, grounding strap & rear bezel wiring, its easy ) wise choice to replace fuel lines from tank to engine. Use the diesel hose for the entire lengths - got mine from Larry B's. Mine developed pin hole leaks from corrosion which led to a hard start issue. I replaced the module also. Rotted out. (expensive dealer item, consider GAmes offer in pay it forward) Your problem should be solved. Good luck... Mike

 

[Joe G.]

JLC1,

This could be pretty simple. The large white plastic ring nut that holds the fuel module in place could be leaking. Try tightening it up. You can do that with a long screwdriver and a hammer without lowering the tank or raising the bed. It's a tight fit, but you can get to it sitting under the bed on the outside of the frame rail if the truck is jacked up a little. If it's leaking and that does not work, then you have to replace the rubber gasket. In order to do that then you have to lower the tank or raise the bed.

 

[JLC1]

Came across this old post of mine while searching for something else. I did remove the bed and found many things.



1. The the lines going into the tank were corroded and broke off trying to remove the quick connectors from them. Replaced it with a Drawstraw in the factory module.



2. Tank straps were corroded. Replaced with new from Dodge.



3. Steel lines, supply and return, looked bad and when checked with compressed air had holes all over from rust. Replaced them with trident lines.



4. Brake lines also didn't look good. Replaced with stainless steel replacements. (Waited along time for the lines).



Truck has been starting perfectly to date with no fuel system issues.