Engine/Transmission (1998.5 - 2002) Lift Pump PSI w/just key on?

[RobbyRam]

I have 'BriarHoppers' gauge hooked up to the 'pre' fuel filter side schraeder fitting and I get "0" PSI with just the key turned to the start position but not 'bumped. ' Then after starting the motor it very -very slowly climbs to 15 psi(I just had it replaced because it only went to 10 PSI)

The truck is very hard to start now, which never happened with the old pump which consistantly had 5 PSI with just the key turned to the start position.

Is my new lift pump bad?

 

[DarrellB]

You're saying when you first turn the key the pump reads 0psi right.



The pump will only run for about 20 to 30 seconds when the key is first turned on then you will have to bump the starter to get it to run longer.



I would think if the pump is putting out good presure at idle and at WOT then it's not the pump but maybe something electrical. I'm not sure what mine does when I just turn the key on but I know if I bump the starter it will pump 16psi (and it comes up quick too) and will keep 16psi at normal cruising and then only drop to 9psi at WOT.



Then again maybe it is the lift pump going out. It seems kind of strange though.



What does the pump pressure look like going down the road? That I think would be the were you would tell if the pump is going out.



Boy, I didn't help at all did I.



Darrell

 

[DHess]

I have got to get a gage. When you first turn the key to the "ON" position, the lift pump on my '99 runs for 2 seconds - at least it did until last weekend. Now it only runs for a half second if at all. Bumping the starter and the pump will run for the 20 seconds. Haven't checked the pressure but truck is starting and running fine. Is the lift pimp going?



Did talk to one dealer service writer (the truck guy) and he said it was just the purge solenoid and nothing to worry about. Decided it was time to leave - correct me if I'm wrong but only some og the gassers have the purge. The Cummins does not. For the real story, the TDR is the place to be.



Dave

 

[lsenus]

My pump ran for a few seconds every time I started the truck. I waited for the pump noise to stop and then started the truck. This went on for 89000 miles, including 2 minutes before the truck died, and I mean died. Well, a new lift pump and injection pump later, thank heavens for the warranty, I now have gauges. No more guessing.

 

[GeneralMachine]

Lift Pump pressure

After reading these post on pump pressure, today I rigged up a test gage out of a old a/c charge hose, and a zero to 60 pressure gage, I had zero with the key turned on and zero with the truck running. Called the all american dealer and explained the deal and he in stalled a new lift pump and had the truck back up and running in less time than it took to drive it over to the shop. now with the key on I have gage movement, 12 psi at idle and 10 at cruse, 8psi at wot. thank's for you guy's input for maybe now i can save the injection pump. Harv