Fuel Pressure

[Blast7]

I checked my fuel pressure but don't have my manual around so I'm not sure how good these numbers are.
Key on with engine off:12PSI
Idle:34PSI

 

[Cohiba]

That seems a little bit low... my fuel pressure stays right at 42 throughout the RPM band. Not sure what it is with key on, engine off... I'll have to check it out tomorrow.

FYI: Before I put in the 190lph fuel pump, it was around 40.

 

[projectSHO89]

Spec for the 89 is 39 psi at idle.

It should maintain that for at least 2 minutes after the pump is de-energized.

Remember, the pump only energizes for 2 seconds when the key is turn on...until the engine is started.

Steve

<small>[ June 17, 2002, 08:30 AM: Message edited by: projectSHO89 ]</small>

 

[Blast7]

I know about the pump only being on for 2 seconds but I've heard that the fuel pressure is supposed to remain constant even after it shuts off. I have been having problems lately and I think that I've narrowed it down to the fuel pump. Is 34PSI really low when comparing to the 39 or should it be a bigger difference before I replace the fuel pump?

 

[DeaconBlue]

You need to have the vacuum line to the FPR disconnected and plugged to do the KOER test, it should be about 39 +/- 2 psi.

 

[Denny]

Hey, how about ZERO pressure right after you shut off the engine. . .

Yeah, with the FPR the pressure is constant, but when mine was on, it was all over the place, it would dip, (or completely drop and stall) rise up a bit then fall back again. It didn't look like Olympics gauge when he fired up his SHOPAZ

 

[olympic]

If I remember right, mine said 35 PSI at idle and it would jump up to 40 PSI when I revved it. I forgot to test it with the FPR unplugged but I assume it would jump up to around 40psi.