Engine/Transmission (1998.5 - 2002) Dead Lift Pump?

[nhincher]

I checked the fuel pressure this evening for the first time in a looong while. It did something strange. when I first start the truck it's at 12-13psi after 15 seconds or so it drops to 2-3 and stays there, cruising and WOT are at 0... sounds dead to me but wanted to make sure, the high pressure initially seems strange, could this be a gage problem or ???



I've got almost 74K on it, it checked out good at around 55K haven't been to religious about checking it since...



leaving for an 1100 mile round trip tomorrow, I always put these things off



thanks for any input

 

[Sticks]

Uummmm...



Better safe than sorry. Change out that LP. If the gauge does the same thing on the new one, then you have a spare.

 

[Froadin]

Sounds like a dirty fuel filter to me. The LP could always be bad, but to have the initially higher pressure would indicate a dirty filter that picks the crud up that is sitting in the housing up after it has sat for a while.

 

[Gary - K7GLD]

Mine did almost the same thing on our last RV trip, about 350 miles from home - the pusher pump I had added brought us on in.



I replaced the LP with my spare, and then checked the original - absolutely NOTHING I could find wrong with it - I disassembled the pump section, it was perfect - put it back together, tested it for fuel flow and PSI, and it was perfect - my only assumption is that the power connector was not making proper contact, and creating the problem. In any case, the original is now my spare...

 

[KKroack]

dead lift pump

Had the same problem with mine. 32 k miles. bought a elect pressure gauge from genos. got it hooked up, 13-14 lbs. headed for vegas from western CO. Got almost to vegas , noticed it was down to 10 lbs. by the time I left vegas, headed home, it was just like yours. everything seemed to be running ok, so I figured it was bad gauge. WRONG. Checked it when I got home with a mech gauge. Took it in to the dodge place and they replaced the lift pump. My concern, did I hurt my high pressure pump driving home from vegas? Truck ran great and keeps running great. Good luck.

 

[nhincher]

Thanks for all the input. I changed the fuel filter 3500 miles ago, unless I got a bad tank of fuel it should be OK.



I don't have a spare lift pump. I am guessing it's been this way for a while so a few more miles shouldn't hurt to much more. besides it's still under warrantee



I will try to get it to the dealership when I get to my destination.



thanks again

 

[mmclaughlin]

Good luck on your trip nhincher!



When my second lift pump started to fail, I would get a good solid 14-15psi at idle and for easy cruising I would get right around 11 or 12, WOT would be around 8psi. Then every once in awhile it would drop below 8 at WOT. So I figured bad fuel filter. Changed that out, but was seeing the same readings - at least for a couple of days. I was amazed on how quickly that lift pump started to fail. In about a week (about 800 miles), it went from reasonable readings to almost 0 psi. The strange thing about it is that it wasn't always at WOT that the pressure would drop, it was usually when I was going up a long small grade on the highway - just enough to load-up the engine pretty good. If I stepped on it, the pressure would actuallly increase a few psi! At least for just a bit. If I took my foot completely off the accelerator, the pressure would go right to 14 psi. This was my second pump (original location) so I wanted to forget about all these lift pump issues, so I installed the FASS system.



I guess the moral of the story is to pay attention to those readings. Don't wait too long to fix a failing pump, it might end up costing you more in the long run. I find that I always enjoy myself much more in the truck when my pressure is above 10 psi!

 

[nhincher]

Just heard from the dealership, they said the pump checked out and was actually on the high side of the spec. guess I will need to double check my test procedure. They did say that there was a stored code though, injection pump timing fault (something like that) from 10 starts ago. guess I'll just have to keep an eye on things.



The good news is that the believed me that something was wrong with the steering (my regular dealship didn't) they are replacing upper and lower balljoints and a couple of tierod ends. Looking forward to driving it back home now!

 

[Tom L]

Hey all, The pump problems sound familiar, I too had erratic readings and decided to remove the pump(5000)miles on it. I put the old one on and the pressure stayed steady tho a little lower than what I have seen as "normal" readings from the prior posts. I took the pump to Cummins where I bought it and it checked ok on the bench pressure test. They said put it back on and we'll re-test and replace it if it isn't up to snuff. I said to H*** with it and designed a rear mounting/plumbing/elec set up and moved the pump to the frame about 10 inches in front of the fuel tank, the old pump(39000+)is back in service and holds a steady 13. 5 pounds at idle, 10-11 at cruise and has not dropped below 8 at severe acceleration, a tt bit more pump motor noise tho. That I can live with! End of story... ..... for now! Tom

 

[Sticks]

Ahhh... Moving it back to the tank. So simple and such positive results.



DC, ARE YOU LISTENING?!?