Over the last few weeks my GTA has been getting progressively slower. I've since found that i'm dumping fuel pressure under load. I set my pressure regulator at 50psi and it drops to around 40psi and the engine pings like crazy under severe load. By "severe load", I mean foot on the floor while doing 50mph. The trans downshifts to 3rd and the engine just pings and the FP drops. Also, the needle on my FP gauge dances around at idle and in OD and only becomes steady under load. It bounces from 35psi to 60psi. My timing is set at 6 degrees. I'm pretty confident the ping is caused by the lean condition and not spark knock. I just replaced the fuel filter. A reliable source mentioned that the sock on the pump may have collapsed. How can I narrow it down to injectors, regulator, or pump? Here's my mods if that's relevant................

355 10.8:1 compression
LPE ported Edelbrock RPM heads
CompCams 1.6 ratio Pro Mag roller rockers
LPE "219" cam
SuperRam
Accel AFPR
LT-1 (24 lb) injectors
Accel 300+ ignition box
Ed Wright custom PROM (garbage)
Precision Industries Vigilante 2600rpm torque converter

Thanks,
Paul

P.S.......My fuel pressure also drops to around 15psi very quickly after I shut the car off or cycle the pump before start up.

 

i'd suspect the fuel pump, if you have to drop the tank for the sock, replace the pump. you can blow the sock off with air blown into the line, but i don't know if i'd want to do that or not.

 

Thanks for the reply. I was just out messing with the **** box again and I noticed that the fuel pressure now drops from around 45psi to 0 in about 20 seconds when I shut the car off or ctcle the pump.

 

ttt

 

Son of a bitch.....I just replaced the pressure regulator and it was wroking fine after I put it back together.......then it wouldn't hold more than 40psi. It was working great but then it started just sitting at 40 when I got on it. It holds when I shut the car off now. So now I have a new pressure regulator and a new walbro pump but still no fuel pressure.

 

ttt

 

Z,

By your accounts so far, it seems that the regulator solved the leak down problem. You may need to adjust the regulator now. If you are afraid that the pump is going south on you, perform a dead-headed pressure test (pinch the regulator return line to test for maximum pump pressure output).