Fuel pressure issue

[BOP4ever]

I checked my fuel pressure yesterday it was 42 line off so I raised it to 44 since was lean on top end.
I also notice that turning the key on gave no pressure until I cranked the car.
Also when I shutdown the pressure drops off pretty fast to 20
And continues to fall ....
Looking for some input.

 

[MaxVO2]

I would think leaky/dirty injector, and/or leak back at the pump at the hose from the sound of it.

I recently changed out my old Red XP pump to something more modern and found that the new gas being sold in my area had enough ethanol that it ate the old rubber fuel injection line to the point that it split and was leaking a bit out the side causing the symptom you describe.

Hope it's just a leaky injector as those can be cleaned easy versus dropping the tank, etc..

Billy

 

[phil_jordan]

it sounds like your relay is bad. I dont see anywhere in your sig of running a hotwire, and I dont want to "assume" you have one ran. if your fuel pump dont run for 2 seconds with key on, its most likely your relay.

 

[turbofrank]

fuel pump

 

[Grunk]

Agree sounds like the fuel pump. I did the same drill changed the fuel filter, the FPR and turned out was the pump.

 

[aminga]

Could also be the FPR

 

[Ttype6]

I checked my fuel pressure yesterday it was 42 line off so I raised it to 44 since was lean on top end.
I also notice that turning the key on gave no pressure until I cranked the car.
Also when I shutdown the pressure drops off pretty fast to 20
And continues to fall ....
Looking for some input.

The only thing you need to know is if your fuel pressure rises one for one with each lbs of boost up from your base pressure (line off).
The only way to know is to watch a gauge during WOT while noting boost.

 

[MaxVO2]

Ya, of course the above regarding 1psi rise in pressure for 1psi of boost is true but if the guy has a leaky injector the fuel pump will deliver fuel but the injector could still have a poor enough spray pattern that the cylinder goes lean or rich and causes problems. I didn't drive my GN so much for a while and ended up replacing the pump due to a hose issue to still find a pressure drop off as described above. I guess the old fuel caused varnish to form on some of the injectors as the pressure would bleed down almost immediately after shutoff. This was after several months of not starting the car even though I used Sta-Bil for the fuel, etc...

After cleaning the injectors with a kit I bought that attaches to the fuel rail, and uses a concentrated solution under pressure, the bleed down rate was much slower and I still had over 25-30 psi pressure after 8-10 hours overnight.. My BLM, INT and EGT were also more normal for my combo after I cleaned everything up and replaced the pump, etc..

Just a thought in case the relay and pump check out ok.


Billy