hey guys, my car is running really really lean at WOT. My 02's are in the 50mV range....they should be in the 850's!!

Now, a little background. I have a pretty annoying idle/surging problem that is probably a vac. leak. It does it at idle from like 800-1200rpm give or take, it is WORSE when the car is in park or neutral(better under load) and it changes its attitude as the car warms up...very weird. Sometimes, at night or in certain temperature it behaves pretty normal. And sometimes it is so ridiculous i shut the car off and wai a few minutes and restart hoping "i can trick it" LOL>>(joke's on me)

ANYWAY...a few months ago when i finally got the 383 in i set the WOT FP at 50 psi for starters(vac. line off regulator, etc).

Today I was trying to make sure i needed a fuel pump(unrelated to idle problem), but now I'm not so sure. I hooked up the FP guage and pulled the vac. line off of the regulator. Primed the pump (key forward) and the FP jumped up to 60psi! So i ask myself #1: how did the FP rise if i set it at 50 psi? #2 why did the car get slower and LEANER than before when i set it at 50 psi if the FP is now higher?

So, i purge the guage, do it all over again...same stuff.

Next, i started the car and HERE IS WHERE i know something weird is up>> the guage was bouncing around so rapidly and off the charts from like 40 psi off to over 100psi and off the guage. it was flickering back and forth like a mad-man! Unreal.

SO, my question is....what can be wrong with it and what is causing what to do what???????? Is this causing that or that cauing this....regulator shot???

I'm lost here...pretty new to EFI :/

 

Either your FPR is bad (less likely) or your pump is bad (more likely). This is tell-tale for a failing fuel pump. Usually your car will buck under these conditions. Mine does! (I still need to replace my pump. Just haven't gotten around to it).

 

Yeah, I believe Mangus is correct. There's really not much to go wrong with an AFPR/FPR; it's a rather primitive device. I'm not too familiar with electric fuel pumps, but know enough about electronics to know that a failing electronic device can do just about anything but work right. Is it a factory FPR? If so, you'll be needing an Adjustable FPR (AFPR) anyway if you've dropped the TPI setup on a 383.

And Mangus, have fun tackling that chore! The last time the pump was swapped on my car they forgot the wire for the fuel level gauge! But weren't about to go through THAT routine again just to hook it up! (Previous Owner) - My manager at work actually cut a small "service door" in the floorpan just so he wouldn't have to drop the rear end on his Firebird - we still harrass him for that one

 

hey, i replaced the pump w/ a Walboro 255

OMFG the car came back to life. It is waaaay rich now but a lot aster then when it was waaaaay lean LOL

I ditched the pulse dampner as well....STILL have the same problem. Guage is all over the place :/ It tested fine on another vehicle.

I'm working on getting another Adj. FPR. from the looks of the pics, mine is an Accel. When i had it off i didnt see any markings that could verify that though