Engine/Transmission (1998.5 - 2002) Lift Pump

[whiteram]

Has anyone had problem with lift pump power supply?

 

[nps]

Yes. Why?



Welcome to the TDR. See this is your first post. If you can give more details about your truck and the question, a more direct answer can be provided.



Early 24V trucks had lift pump wires that were exposed and subject to corrosion (12V engines have a mechanical pump, thus no power).



There has also been discussion on corrosion at the lift pump relay. It's located under the hood on the drivers side.

 

[whiteram]

2000 24 valve. 2500 4x4. Engine cut off and I checked pressure at rail. No fuel there. I have ordered a pump and I was wondering if there could an electrical problem. Thanks

 

[nps]

You won't see fuel pressure unless the lift pump is running. The ECM controls the LP. When you turn the key, the pump runs for about 2 sec but then shuts down and doesn't start up again until you crank.



So get in the truck and 'bump' the starter. This should cause the LP to run for 25 seconds. Then listen for the LP running, and check at the schrader valve on the side of the VP44 for fuel pressure.



Typically on a 24V, the LP failing won't cause the engine to quit. There is a remote chance the LP failed and blocked fuel flow, but most don't. The VP44 continues to suck fuel through the LP, which is bad for the VP44. So what may have happened is the LP failed some time ago, and the VP44 recently died because of it.



Check the codes by cycling the key on-off-on-off-on. The codes will display in the odo window, and may help to point at the problem.



If you have less than 100K miles, both the LP and VP are in the 5 year/100K warranty coverage.