Originally Posted by vital49
I've had a suspicion that my pump is slowly dieing on me. So, this past weekend I finally hooked up a fuel pressure guage. I'm getting 48 lbs. with the key on, engine not running. With the engine running I'm getting 40 lbs. The odd thing is (maybe it'* normal) when you rap the throttle the pressure spikes to ~55 lbs. and then snaps back to ~35 lbs. If I hold the throttle at about 2,000 RPMs I'm able to maintain 40 lbs. of pressure.
Is that normal?
My fuel pressure regulator was replaced this past winter thanks to the GM recall.
The reason I thought my pump is getting weak because I have a high RPM stumble that I can't seem to cure. It'* gradually getting worse. I've done all the tune up things to it and just can't cure it. Plus, my sender is bad (guage doesn't work....and yes, I'm positive it'* the sender).
With the key on I get 52 psi, engine running is more in the neighborhood of 40-50psi depending on manifold vacume to the FPR...
Its strange tho, The best I could do on the old pump was 47ish, and that was with the key on if memory serves... I never did any better than that when I hit the throttle... It would usually drop off... Lowest I saw at one point was 32psi... Usually idle was 40psi, hold 2000 rpms or so and the pressure would go down to 36-37psi... Seemed like the Fuel pump was not keeping up with demand... I thought it may have something to do with the strainer sock, but the tank was clean...
After replacing the FP and the strainer sock I have 52psi with the ignition on, 40-42 at dead idle, and when I hit the throttle it goes up to 50-52 really quick... Exactly what its supposed to... Runs a ton better...
Also my FPR was replaced about a year ago due to fuel pressure issues... It helped some, but the pump was making more than enough noise to be heard... The new pump freaked me out.... After the install I hit the key, and I heard nothing... I thought * Oh **&^ * Thought I forgot to plug the connector in...LMAO... The pump was just super quiet... lol..
Not too sure what to tell you about your pump... My pressure was off for the last 20,000 miles... I just didn't trust the amount of noise that pump was making, plus the low pressure... So I decided to replace it...
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