Fuel pressure drops when reved
Asked by Mike May 07, 2021 at 03:22 AM about the 2005 Chevrolet Cavalier LS Coupe FWD
Question type: Maintenance & Repair
2005 Cavalier has a intermitten lean condition. PO171 is the only code. Car will
fall on its face acceleratimg only after full warmed up, never cold. I hooked up a
fuel pressure gauge to the fuel rail. It read 49 psi with key in run position. It also
read 49 psi engine idling. However, when i reved the engine to 2000 to 3000
rpms the fuel pressure dropped to 20 psi. Pulled the vacumm line from fuel
pressure regulator and no gas dripped out but no i provment in fuel pressure
either when idling.
7 Answers
I would say 1st of all you don't have enough fuel pressure without knowing specifications. But I'm an old school mechanic and this is what I would do to know for sure if u have enough psi. Take fuel line off
and plug line with thumb, have someone turn the key to the on position, IF u can hold the fuel from spraying out your pump is weak and replace it
Putting your thumb over the fuel line is a good way to inject gasoline into your blood stream.
Unfortunately the fuel filter was replaced last may when these problems started. The fuel pump was replaced ln december 2019 but the filter was not replaced at the time. Then a few months later in may 2020 the filter was replaced when intermitten lean issues started happpening on long drives.
