mabe fuel pump..idk

transAMdriv3r · 12-09-2006, 03:15 PM

My car is in my sig, but anyways I had it scanned and no codes came up. The car stumbles when under load but idles nice and has plenty top end power. I rebuilt the motor last year, and only has about 1000 miles. The motor pretty much has new everything except injectors and icm. I do hear slightly than normal whizzing sound and it seems to be coming from the fuel tank ( probably fuel pump or exhaust leak, but i cant pin point it) I am going to have the fuel pressure test this week sometime cause the mechanic said it may have good fuel pressure, but the volume might be low. would this be the cause of my low rpm stumbling that ive been trying to track down.

Ill let you guys do your work

OBE1 95Z28 · 12-11-2006, 10:01 AM

A fuel pressure gauge indirectly checks volume. Tape the gauge to your windshield and watch the fuel pressure as you drive at WOT. If the volume can't keep up, you fuel pressure will drop off.

transAMdriv3r · 12-11-2006, 12:22 PM

thank you....i just bought a guage and will do that now. i have also notice that whizzing sound is more pronounced and getting louder. ill post my results sometime soon

transAMdriv3r · 12-13-2006, 10:52 AM

just had it tested... fuel pressure is at 34 and steady, should be at 41-47

OBE1 95Z28 · 12-15-2006, 02:22 PM

Just to be clear, 41 - 47 psi is for WOT, 34 psi for part throttle driving is normal. Your fuel pressure regulator has a vacuum line that adjusts the fuel pressure based on manifold pressure (vacuum). Part throttle driving has a higher vacuum than WOT (low vacuum, nearing atmospheric pressure).

transAMdriv3r · 12-15-2006, 06:32 PM

wide open it didnt change...so i just had it replaced. works good now