j-dubya

i just got back home from the military last friday, and i leave again this friday - only this time the truck is coming with me. so i have to get this taken care of asap. anyway, i went in there messing with the injectors. after putting back together, i cranked and drove around twice that evening. no probs. next morning, hard starting. i took everything apart and retorqued. everything looks good. flares have good surfaces, o rings are brand new, and no visible fuel residue on the injector lines/head. well, i had the hard starting for two days now, until tonight, when i filled up my tank. when i began getting the symptoms, the tank was just above a 1/4 tank. now full, diesel began spilling out the top of the tank. it was dark, i could not see, and my pump has no "clicker". i was going by sound. i go to move it over to my garage to have some better light, and the truck fires right up just like it used to. to make sure it wasnt a fluke, i waited about half an hour and again, it fired right up. before, hot or cold motor, it was like priming the system all over again, everytime. it seems as tho ive read about this on here somewhere, but no i cant find it. ive got to figure this out before i get on the road. no loss of power/drivability, mileage i cant tell, everything is working fine. but the leak at the tank, i have never had before, and the hard starting before the fillup i cant solve. i have gone over eveything i can think of, to no avail. fuel pressure is good, 15-16 idling. cranking has good pressure. i am an experienced mechanic, but still kind of new to diesels. any help greatly appreciated. sorry for so long.

thanks,

jeremy

donhov

Just a thought, could it be the lift pump? When tank is full it may create enough pressure to prime the CP3 (VP44 in your case?, not sure) and with the full tank it is pushing fuet tot eh pump and not counting on the lift pump. Or maybe the pickup tube has come off the bottom of the tank and wasn't picking uip fuel OK? Like I said, just randon thoughts.

j-dubya

lift pump is a year old, but has only around 2000 miles on it. fuel pressure is good no matter how low the tank or hard starting or not. your thought of the pickup in the tank is interesting. i still am trying to figure out if there is a relationship between the tank and my injector rampage earlier, or if something happened around the time of me playing with the injectors and i am blaming the wrong area. air is getting in somewhere...

jeremy

Kevin B

I'll throw in my $.02 here. What if there was a crack or leak in the feul pick up tube inside the tank kinda toward the bottom. Could that introduce air into the system even while showing good F.P?

Im kinda new to these engines and im not sure if the can purge air from the system in a case like that, but we had Kenworth long ago that was doing something like that and that turned out to be the problem.

Anyway, thank you for your service to this country and good luck.

Jim Dynomite

My wifes '02 does the same thing at around 1/4 tank. Hers also spills over out of the tank bulkhead when filled to the top for some reason.

Wondering what these to things have in common?

I have'nt had a chance to dive into it, like said above maybe the pick-up tube is defective, so I just keep it filled.

Bump this to the top again in the morning.

Good luck.................Jim

natsys

Last summer my 99 2500 started producing a puddle of diesel when parked. If you can get yourself between the frame rail and the bed wall/skirt on the driver's side in front of the rear axle you can just peek over the frame rail and see the top of the tank. My fuel pick up and return elbows going into the tank were junk. Made of steel they just rotted out. It was the return line that went first, the pick up line was still drawing, so when excess fuel returned to the tank most went in, some did not.

To fix it I had to drop the tank. (2) 15 mm bolts (deep socket, long studs) on the driveshaft side to hold the tank straps--supported below by my forklift at work. Make sure to disconnect the fuel filler and breather--I found them to be easiest to take off the tank, not the filler end (hose clamps, (1) 1/4" fitting, the other 5/16", then twist the hose). Then I could drop the tank a few inches and disconnect the fuel lines--actually, they disconnected themselves, but the pick up line wasn't that bad yet and it goofed up the plastic connector to the fuel line going to the lift pump. You can buy those inserts at your local parts store, but it is more prudent to use the proper disconnect tools to release the fittings first. Also unplug the wiring harness. Then the tank was completely free and I dropped it and pulled it out.

The lines are connected to the fuel sender which is a cylindrical shaped unit that drops into the top of the tank. Unfortunately, it cost $317.00 (4897668-AF MODUL KIT 14067004) and there is no alternative. You can't just replace the steel fittings, you've got to replace the whole thing. The new unit is redesigned (what a surprise) and has plastic fittings instead of the steel ones.

If your sending unit is the old kind with the steel fittings I'm pretty sure that's where your leak is, and getting air in your transfer lines would cause the kind of problems you describe.

Timmay2

Low fuel = sloshing. Could be picking up some air in the fuel, even if the pickup is submerged there is air bubbles in the fuel.

Smokee

Just a guess, but my suggestion is that when the tank is low, and the fuel in the tank and lines becomes warm, once the engine and fuel cool down a small air leak sucks fuel into the lines when the fuel contracts as it cools overnight. When the tank is full, the fuel doesn't become as warm.
Makes sense to me.