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Something about that pressure!

821 Views 2 Replies 2 Participants Last post by  Beef supreme
Alright guys, I think my fuel pump may be going out but I'd like to run it by yall and see what you think and also which parts to check out.

Key on fuel pressure (no ignition): first turn will put it anywhere from 15-25, second turn will kick it up to 35ish and then the car will be able to crank. The pressure will also bleed down very fast, in 10 seconds or so it will sit at 0 psi.

Idle fuel pressure: 32 PSI
Idle fuel pressure with FPR line disconnected: 43 psi

I pulled the fuel rail and saw no fuel leaking down when key turned.

The pressure does not increase even under WoT but under WoT there is no surging, bucking, bogging or any driveability problems.

The car will also surge under constant light acceleration.
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Since you have 32 psi with fpr in loop and 43 psi when you remove fpr from loop, I think you have found your prime suspect. The fpr would be my choice. If fuel pump was bad pressure would not rise to 43 psi when you disconnect vacuum line to fpr.

sounds like fpr is leaking fuel back to tank, just enough to lower pressure and cause rapid bleed down when pump stops.

Check ball in pump could be bad, but again first choice is fpr.
Alright I'll order a FPR tomorrow and pop her in. The gas definitely isn't going into the block.

Thank you!
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