Low Fuel Pressure

Have 2000 Impala with a 3.8L. Was having a hard time starting it. It would start for a second and die. This usually occurred after the car was warmed up. When cold it would start first time. I just had all the spark plugs and wires replaced this past April when the intake manifold was replace because it was leaking, and they were due to be replaced. So my first though was the Fuel Pressure Regulator because when I first got the car 10 years ago it went bad and gave the same symptom of a hard start. Checked it and it isn't leaking so I checked Fuel Pressure and it was only 40psi at the rail.... So I was thinking fuel pump or fuel filter. The fuel filter was also replaced this past year so I went ahead and replace the fuel pump in the car. The car starts fine warm or cold now, but the fuel pressure still only shows 40psi????? Any thoughts????

-Xlr8r

Gage inaccurate?

Gage inaccurate?

Don't think that's it...Used 2 different gauges but they were made by the same company...

what brand were the parts??

was the old pump bad??did it hold pressure??did it increase w/unplugging fpr??
just a thought, i understand its starting better now

what brand were the parts??

Everything is factory except for Fuel, Oil, & Air filter that are Wix.

Could anyone give me what the Fuel Pressure PSI range is on this car with the Key on and then also running?

47 is about right.

47 is about right.


Well I get that with the car on but not running...When the car is running it drops to about 40-41.

What else should I be looking at. It seems to be getting worse, but will not put out a code....Sensor maybe?

So what is the issue, how does it run? The pressuere is still in range running.

So what is the issue, how does it run? The pressuere is still in range running.


The car just doesn't like to start when warm. Cold starts seem fine. Warm start it will start and die right away or if it does try to run on the first time it will be real rough running and longer crank times. Could it be the ICM after it has warmed up? How would you test this? It never has given me a code though....Once you get it started though it runs fine....

The car just doesn't like to start when warm. Cold starts seem fine. Warm start it will start and die right away or if it does try to run on the first time it will be real rough running and longer crank times. Could it be the ICM after it has warmed up? How would you test this? It never has given me a code though....Once you get it started though it runs fine.... like he said should run with that pressure are you getting good spark to plugs and it should be blue spark? next if got good or no spark cps sensor.

Symptoms like that may be a dirty throttle body and iac passages and pintle, possible leaking injector also.

xir8r,so going through your posts changing fuel pump did not really help
you still have a long crank/hard start when warm.
the best reference on f/p pressure is 48-55 i dont have manual for 2000 impala
the specs come from a 99 park ave 3.8 which should be the same or close
i would recheck key on 48-55, eng.run should be 5-10 psi lower, eng.run w/fpr unplugged should increase psi 8-10. the system should also hold pressure 5min
with out losing more than a few lbs when shut off.

Low fuel pressure would usually cause hard starts cold, as the increased pulse width demand coupled with low fp would cause poor atomization.

I don't believe I have a fuel pressure problem anymore after the replacement. Would an exhaust leak cause this kind of problem or have anything to do with it? I think the seam in the resonator has an exhaust leak. Tested for spark and everything seem to be fine there....It maybe just something I live with until it gives me a code or won't start anymore....