fuel pressure
 

checked fp readings on my car today. think pump may be going bad just need some opinions.
fp idle 34 psi
vac line off 45 psi
wot drops to low 30's psi by about 5k rpm before i let off throttle
does get kr under load up top on scanmaster but not always
the car is a 95 canaro m6 few bolt-ons shorty headers and catback also pcm4less tune.

Re: fuel pressure
 

You shouldn't see anything less than 40psi at WOT/max RPM/max load. "Low 30's" would indicate a problem with the pump, the filter or the fuel pressure regulator.

Re: fuel pressure
 

forgot to mention replaced fuel filter this morning also and when i took off vac line off fpr didn't see or smell any gas

Re: fuel pressure
 

does anybody know if this is a bad fuel pump or bad fpr.
how can i tell which is going bad. i changed filter and checked fpr vac hose to see if any gas was present and there was none any help apreciated

Re: fuel pressure
 

its the pump


regulators usually show problems all the time, pumps often show it under load(cannot keep the supply steady to the demand of the engine)

Re: fuel pressure
 

sounds like the fuel pump.if it was the regulator you could tell by turning the key on but not starting the car.your fuel pressure should come up to 43-47 lbs and hold.....if it drops quickly its a good indication your regulator is bad.if it drops quickly you can install a shutoff valve on the return lin...or if you brave pinch it....if the pressure holds and then drops when you release the return line it a bad regulator.after starting the car you fuel pressure should drop by 3 lbs or so and go up at wot.if you pull the vacuum line at idle it should pop back up to the 43-47 lbs and hold.most likely it sounds like a pump.hope this helped