97 fuel pressure?
nxk2000
07-11-2007, 09:06 PM
What holds fuel pressure in the system? The regulator is one but can a bad fuel pump also cause pressure to drop off? Here is what’s going on. If I turn the ignition on the pressure jumps to 58 psi. It then drops back to 0 when the pump stops. After cycling the ignition a few times it would hold pressure at 50psi about 10% of the time. When it does hold pressure it will hold it until I cycle the ignition again. The reason I was looking into this is the fuel pump has been acting up. Sometimes when the pump kicks on it pulses a few times before running normal.
wafrederick
07-12-2007, 05:48 PM
The fuel pressure spec 60 to 66 psi.GMs will not run on the lowest fuel pressure.Stay away from aftermarket pumps,they are junk and the warranty is mostly rejected because they call it installer error.Get one from the dealer,the AC Delco fuel pump although it is more money.I know about it,put in 6 Airtex fuel pumps in one Chevy pickup and my father hated that.Switched to Carter,had good luck with them and they failed just recently.It was my cousin's 2001 Oldsmobile Alero,put in 3 Carters and they failed right away.Finally put in an AC Delco pump and has not come back since.
MT-2500
07-13-2007, 08:38 AM
What holds fuel pressure in the system? The regulator is one but can a bad fuel pump also cause pressure to drop off? Here is what’s going on. If I turn the ignition on the pressure jumps to 58 psi. It then drops back to 0 when the pump stops. After cycling the ignition a few times it would hold pressure at 50psi about 10% of the time. When it does hold pressure it will hold it until I cycle the ignition again. The reason I was looking into this is the fuel pump has been acting up. Sometimes when the pump kicks on it pulses a few times before running normal.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
nxk2000
07-13-2007, 03:44 PM
Maybe I put too much in my post.
With a bad fuel pump can pressure leak back through the pump?
With a bad fuel pump can pressure leak back through the pump?
MT-2500
07-13-2007, 04:53 PM
Not while the pump is running.
Go threw the fuel pressure test I posted and post back the pressure readings.
Go threw the fuel pressure test I posted and post back the pressure readings.
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