Engine/Transmission (1998.5 - 2002) Fuel presure on startup question???

[Ramingit]

I just hooked up a fuel pressure gauge and noticed on first turning the key on that the pressure comes up to 10 psi while the pump is running and when the pump turns off the pressure drops to 0 psi. The pump only stays on for about 10 seconds. After I start the engine the pressure is 10 psi, WOT is 2 psi.



I know the pressure is low and I am going to replace the pump and relocate it by the fuel tank.



I would like to know if the pressure drop off is normal after the pump stops running before starting the engine?

 

[obert]

The pressure drop sounds OK, mine does that anyway. I dont think the pump holds pressure, so when it stops, the perssure drops off, too.



But you have a 10 sec key on pump cycle??! That does sound strange. Depending on the software in the ECM, the pump goes from just a "bump" to maybe 2 or 3 seconds.

If you bump the starter you should get about 25 seconds to help prime the fuel system, after a filter change, for example.

 

[JCyrbok]

Mine only runs for about 2 seconds when I first turn the key on. That equals about 3-4 psi on my setup. Once started i get 15-16 psi at idle.



J-

 

[Ramingit]

Thanks for the info on the pressure drop-off, I got the pump relocation kit from Genos and I will install the new pump this weekend. I hope it brings the performance back. .

 

[rweis]

The reduced psi at start is to make it easier to start. High fuel psi's at start will cause hard starting.



I remember the start psi is like 7 psi then 15 psi for running psi.



Bob Weis

 

[Graphic man]

you just need to up-date software to the ECM to bring it down to 2 sec.



DC can do it for you





Scott