I just replaced my lift pump as the truck was running like crap with usual symptoms, has been great for 2 weeks, then tonight I put it to the floor, and it started quickly dying after sitting at about 2700 rpm for a few seconds. This time it is no where near when the lift pump was dead, its more like a quick "bang" then i let off and let the pump catch up and its fine. No stall or anything as long as I let off completely for about 10 seconds. I have not yet looked at anything, but is it possible I may have a small air leak at the lift pump, or even possibly a partially open T valve or bleeder? They were all opened when diagnosing the lift of course. I just left my buddys place with him, and as soon as I turned the key on to warm the glows, he said he got a small wiff of diesel. Anything else I should look for? I am looking in the morning.

THanks! btw its a 98 F code 6.5 in a CC 2500 SB 4x4 with an auto.

Check the sock in the tank... likely plugged up starving the engine. do a search "snot in sock or tank" or something to that effect, good write up on it.

Check around for "wet spots", sometimes the fuel filter will leak and only leave a residue under it in the engine valley.

x2 on the sock check. Pain the butt to do, but a needed item after x-amount of years on the road. Search for snot-in-my-stockings thread. Look in FAQ's.

Any air accumulating in the fuel filter ?
If so the fuel lines my have a small hole on the suction side between
the tank and lift pump.

Thanks for the imput guys, I am going to check the fuel filter now, and also the sock (hopefully later this week) My sending unit is pooched anyways so it has to come out.

I am really getting frusturated now. I am totally back to square 1 with the way the truck was before the new lift was installed. Pump is running, but I have nothing up front at the T valve or coming out of the bleeder at the fuel filter. I guess my next venture is to rip the box off (again) and pull the sending unit and check the sock tomorrow?? Any other ideas?

Why pull off the bed dropping tank isn't that difficult a task, I've got it down to about 20 minutes, "with empty tank that is" just for grins prior to dropping tank remove the lift pump inlet, apply about 3-5 psi air pressure back towards the tank until you hear bubbling from the fill, that will temp "de-snot" the sock if that is your problem, and you can then reconnect the lift pump and jumper it to run again pics & info in FAQ ops/lift pump reference material so you can check before dropping tank or bed if snotty sock is the issue, if blowing back towards the tank clears it then you gottta clean the tank & sock.

Thanks for the info guys, for sure. I am going to take the box off though, I can do it in about the same amount of time. It has already been off once, and I put antisieze on all the bolts, even the 5th wheel bolts. The other reason is I have no clue how much fuel is in the tank as my gauge doesn't work. Acoording to my calculations :rolleyes: it should be sitting with about 50 litres in it... but I really don't know!

I must extend a great thank you to all that have answered my thread. I pulled the box tonight, yanked the sending unit, to find.. over a half tank of fuel (was happy about that one!) my sending unit wires unplugged (on the inside, not near the frame, so very cool now I have a working fuel guage... and the sock covered in a nice black tar sort of crud. Replaced and wow what a difference! All stumbling problems are again gone, but the power increase is phenominal compared to before! I wonder if the restriced flow of the fuel played a part in killing my lift pump. My old pump still ran, but pumped no fuel?? I still have the old one and am going to actually test it out of the truck, it may be possible that I did not even need a new lift. :D