Archived Big Time Fuel Leak

[Treb]

To start off, this is a 94 with 255,000 miles.



Last night after my wife got home from an approximately 100 mile drive (where she had a flat tire and had to have the rear tires replaced), I noticed a puddle of fuel under the truck. After this, I started the truck and put a flashlight on it. There was a steady stream of fuel running down the frame and dripping onto the ground. I try to trace it back up, and I can get up to somewhere around where the fuel filter should be (I have the prime loc remote fuel filter) and there's just fuel spraying all over back there. Can't see where it's coming from because there's too much in the way. It seems to be pulsing and also seems to be RPM depended. . . When I rev the engine, more fuel seems to be coming out. It's hard to tell, but it looks like the fuel is coming from somewhere just above and to the left side of the starter. Shouldn't be any fuel lines over there, though. Am I right???



Anybody have an idea? Also, how hard is it to move the master cylinder out of the way? Might be able to see it from the top if it wasn't there?



Any help would be greatly appreciated! Gotta have this thing running by Monday so I can get to work.

 

[DigginDad]

Sounds like a fuel return line, could be wrong though dont know the truck that well.

Good luck though.

 

[Treb]

found the leak

It's a rubber hose coming out the back of the (lift pump? doesn't look anything like the picture in the book) but man is it hard to get to. Does anybody know what you have to do to move the master cylinder out of the way? Is it easier to just do it by feel, or to move the master cylinder. Really don't know how hard it's going to be to move. . .

 

[crabman]

Treb,

Remove the P/S bolts/nuts on the master cylinder and it should pivot out toward the D/S fender.

These lines are a real PITA to replace so only use marine grade fuel lines. Here is a place to purchase them. V

If you are not tall and do not have long arms it is a good idea to build a platform to stand on to help reach into the area. They also can be replace from the bottom but it is harder if you have a 4wd.

It takes lots of patience. :-{}

Oh, almost forgot, afterwards you will need a first aid kit for your arms and hands.

Good luck!!

crabman

 

[Treb]

Pita

Wow! You are right. PITA might be an understatement. That totally sucked! #@$%! Took me about 4-5 hours. My forearms are completely raw, my knuckles are bleeding, and I'm all scratched up.



I ended up taking the master cylinder off, also the starter. Went ahead and replaced both lines while I was there. Wish I'd saw your post about the marine grade lines before I did it. I just used regular fuel line hose from O'Reilly's. Will it last? I rerouted it so it's not rubbing against the block. The short hose was still the original. I'm surprised it lasted that long. Still had the PITA OEM clamp that you have to cut instead of loosen with a ratchet. #@$%!



I think it would be impossible to change those lines without removing that stuff. The hardest part for me was getting the bottom clamp off (and back on) on the long line.



Good news, though! At least it's done now and it's not leaking any more!

 

[SDrake]

My 94 with 235K on it has had it's third trip through this. Just before the last time learned about the marine grade hose. The fuel hose I bought at NAPA one time and at AutoZone another lasted less than two years each. I was just disgusted with the whole scenario on an otherwise trouble free truck. But with mine the problem originally showed up as hard starting that got harder and harder until almost impossible to start with still no fuel leak. It was letting air in but not leaking fuel. This progressively harder starting went on for almost a year. No one could figure it out. One day I noticed a few drops of diesel dripping to the pavement after a quick trip into a store and back out. I tracked down that leak, replaced the line and starting problem disappeared. Your check valves in your fuel pump must be really working perfectly if you did not experience the hard starting.



I don't know about O'Riellys hose but my my hunch is you need to have some marine hose on hand to replace what you just did in another year or two.

 

[crabman]

Treb,

SDrake is right about the longevity of the fuel hose you bought. About 2 years is max and you get to do it again. The wall thickness of the marine grade hose is about 3x that of regular fuel hose.

The First time I replaced mine, it was the crank more on start with white smoke on startup. I used regular fuel line hose because I did not know about the marine fuel hose either.

The Second time it was the return fuel line which gives you the spray down the engine compartment scenario which is nice to discover while you are driving down the highway. :{ I needed to clean my engine compartment anyway.

I used the marine grade hose and ss clamps which I purchased @ a marine store. The installation time was 1/2 the first time with less trouble as the oem clamps were gone. 1/4" drive socket set w/lots of different size extensions is very helpful.

I also replaced the starter contacts while I had the starter out and cleaned all the wiring surfaces and battery cables.



The TDR is a GREAT resource for information about your truck!!! Good luck on any future projects.



crabman

 

[Treb]

no problems starting

that's really weird, I've seen a lot of posts on here about trouble starting with fuel return lines. . . my truck started perfectly. . . it just sprayed fuel all over the place when it was running. . .



both lines had leaks. . . the short one was only when i put about 50 psi of pressure on it, but it was worn pretty severely. . . the long one had a crack in it that was about 1/4 inch long. . . guess that's the one that was spraying the fuel



not looking forward to doing this again in a couple of years. . . anybody want to buy a good truck?