Engine/Transmission (1998.5 - 2002) Truck only starts with 0 lift pump pressure

[TPlasek]

I have a 2000 with 100, 500 on it. 500 miles out of warranty. I have been having a hard start problem that I worked down to this.



As long as I let the 15 psi of initial fuel pressure drop to 0 (after ten seconds of turning the key on) it always seems to start. If I try to crank on it while the lift pump is still running, most times it will not start.



Is it time for a new VP44 or is there something else it could be that I could fix.



Anyone with knowledge or experience on this matter would be a great help.



Thanks in advance...



ps. pressure is measures at the vp44.

 

[A Johnson]

During cranking you should have 5 PSI or less. If not, you may need to have the ECM reprogramed, (Providing you are not running a pusher pump that is causing the 15 PSI. ).



If you are positive it only starts at 0 PSI or less lift pump pressure, than it is most likely the VP-44 has an internal problem.



A Johnson

 

[TPlasek]

Ok, when I turn the key to the ON position the stock lift pump puts 15 psi to the injector pump. Now when I actually turn the key to the start position the fuel pressure does go down to less then 5 psi, BUT it will not start unless I let the lift pump run its entire cycle until it stops. The lift pump has to stop running and the pressure has to bleed back down to 0 before it will actually start. If not, it just cranks, but never starts.

 

[Opz01]

I had this problem last summer on a trip accross country. I am running two fuel pumps is why. When it happened to me I found that by giving it some gas pedal it would start. Have you tried applying some throttle while your starting?



Opie

 

[A Johnson]

My bet is the VP is toast then. I just tore one apart with these symptoms and it had a galled internal vane pump, and a broken dampner inside.



If this is something you are taking to the dealer to have them look at, and they do decide that its the VP, then I would ask them for Policy help as you are only 500 miles beyond warranty due to mileage and not time, policy is a good will gesture and they have no reason to give it other than they feel nice, but it wouldn't hurt to ask.



On the other hand if you are mechanically inclined enough to T/S to the point you have, the VP is not hard to change.



A Johnson

 

[TPlasek]

I tried the gas peddle thing. It seemed to help when the problem first started. Now it has become worse and more repeatable I can hold the peddle to the floor, it just doesn't want to start.



I fear the inevitable, new VP44 required.



Thanks for the input.