possible bad fuel pump??

[smilts]

Ive been having trouble lately with my 94 GT not wanting to run after a litte bit of driving. Finaly I decided to check fuel pressure after, replacing EGR and EGR posistion sensor. Readings were odd and not overly helpfully to me. KOEO I had around 15PSI. At idle I had 34psi. with mild throttle it dropped down to around 32psi. And dropped to 30psi with a bit more throttle. I'm thinking it needs a new fuel pump. Unless I misunderstand shouldnt the pressure go up a few pounds with load instead of down? When we were starting the car. It didnt seem to smoothly move up the pressure it started at 5psi then yanked up to 10psi and so on untill landing at 34 at idle as well. The fuel filter is about three days old.

 

[toyman]

What I don't understand here is how the fuel pressure can be higher at KOER than KOEO. Yes the pressure should rise with load not fall. Before replacing the FP remove the vacuum line to the FPR. If you can smell or see gas in that line then the problem is most likely a FPR problem.

 

[smilts]

Ok we did remove tvac line and there was no gas visable but i will smell of it tomorrow to double chck and with the vac line off pressure went up to 37psi KOER.

 

[toyman]

Ok we did remove tvac line and there was no gas visable but i will smell of it tomorrow to double chck and with the vac line off pressure went up to 37psi KOER.

That's where it should be. You should also see the same reading KOEO (i.e. same as no vacuum). There should be no smell of gas. Any trace indicates a leaking diaphragm in the FPR.

 

[smilts]

Ill just replace both the fuel pump and the FPR. Are concern was that the problem gets worse when the car has been running for a bit, especialy in the heat. I kinda thought it might be a weak fuel pump getting worse the longer it was running. Thank you for your advice.

 

[KamiKaziDK]

It's your fuel pump, not your regulator. I just had a 255 die on me like that, idled great, but when I stomped on it, it would drop to under 30 and hate life. I have a full sweep gauge, so it was easy for me to test it under load.