Have a 2001 Pontiac grand am gt with the 3.4. After replacing fuel pump and filter with new parts, I'm getting 42-43 psi of fuel pressure at idle. I've ran a snap on scanner on it as well as drop down tests on the injectors. Everything checked out and no misfires. The 02 sensor upstream jumps around alot, from Mid 100's to mid 800's. Would that be an issue? Running regular gas ( 87 octane), no aftermarket parts, and car only has 130k on it. I'm stumped and could use some help as my other vehicle is a diesel and it's over 5 bucks a gallon currently lol.
Fuel pressure issues
- Thread starter Jkreutz
- Start date
92 Sunbird LE
Well-known member
That's low, should be 52 - 59 psi with key off. Check the regulator to see if the vacuum hose is wet.
Doug in P.R.
Doug in P.R.
Vacuum hose isn't wet at all, nor do I smell fuel at the Vacuum port.That's low, should be 52 - 59 psi with key off. Check the regulator to see if the vacuum hose is wet.
Doug in P.R.
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Not exactly sure as it came with the car when I bought the car. It was new in box still .check engine light did come on, cylinder misfire but when I scanned it, no cylinders were misfiring.
92 Sunbird LE
Well-known member
Get another one ( Delphi or other name brand) and see if that helps...( Lifetime Warranty)
Pumps have been known to be defective right out of the box....
Also the hose that attaches the pump to the sending unit could have a crack in it resulting in low fuel pressure. ( Happened to me on my Silverado)
Doug in P.R.
Ok, will have to try thatGet another one ( Delphi or other name brand) and see if that helps...( Lifetime Warranty)
Pumps have been known to be defective right out of the box....
Also the hose that attaches the pump to the sending unit could have a crack in it resulting in low fuel pressure. ( Happened to me on my Silverado)
Doug in P.R.
Thank you
It was working fine, then had injector issues, got them fixed and now pump issues.
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92 Sunbird LE
Well-known member
Blow out the lines too while you are at it( from the injectors back)...what brand of filter? Cheapest is not the best...
Doug in P.R.
Doug in P.R.
O'Reilly bottom line filter, what do you suggest?Blow out the lines too while you are at it( from the injectors back)...what brand of filter? Cheapest is not the best...
Doug in P.R.
92 Sunbird LE
Well-known member
Napa, Wix, Duralast.....
Doug in P.R.
Doug in P.R.
Ok, will get one of those. Before dropping tank again I'll try line clean out and filter change. TyNapa, Wix, Duralast.....
Doug in P.R.
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Has a wix fuel filter now, gained 1 or 2 psi. What are thoughts on a car quest premium fuel pump?
92 Sunbird LE
Well-known member
Ok, awesome