Bouncing fuel pressure needle
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Teching In
Joined: Aug 2017
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Bouncing fuel pressure needle I have a 2001 Silverado with a 5.3 LS1 and LS9 cam. I just got it together and running a few months ago. After sorting out some issues with o2 sensors and vacuum leaks it is running ok. It has a hard time starting sometimes though. I put a fuel pressure guage on it today and with the key on engine off it read 50 psi steady but as soon as I shut the key off the pressure bled away immediately I tried starting it and the needle bounced rapidly between about 47 and 52. What should I expect is my issue? Fuel leak? Bad regulator?
If your battery voltage drops during cranking or even if just the voltage at the pump drops during cranking then that could be the cause of pressure bouncing while cranking. As long as it is solid steady while running it shouldn't be an issue other than the little chase to get startup fuel perfect. How is it while running at idle, cruise, and on WOT pull?
