Low fuel pressure issues are fairly straightforward to diagnose and repair but when something happens you don’t expect it can lead to a hunt for the cause. SureTrack community member mcivortowing had a Pontiac Torrent in the shop that had a stalling issue due to low fuel pressure. They replaced the fuel pump but still had issues. They posed their question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
2008 Pontiac Torrent 3.4L
Low fuel pressure, replaced fuel pump.
Customer says that vehicle runs but then dies.
Diagnostic Steps Performed/Parts Replaced
Verified that vehicle runs and then quits. Performed fuel pressure test. Vehicle cranked and started with 50 psi, then dropped to 20 psi and quit running. Fuel pump replaced with an aftermarket unit. Fuel tank cleaned out. Fuel pressure now at 55 psi, but surging. Started and ran. Went to road test, vehicle started misfiring. Checked fuel pressure. Pressure starts at 55 psi then drops to 18 psi again. Is there any known wiring issues with these units as far as fuel pump wiring? I don’t suspect a faulty new pump, but its possible.
Best Answer from Community Member ericsautomotive
If new fuel pump isn’t a Delco or Delphi pump, it’s more then likely at fault. Also check the voltage supply at the pump. I’ve seen several relays get burnt from bad pumps and start voltage dropping on these 3.4L engines.
New fuel pump defective.
Replaced fuel pump with OEM unit, fuel pressure maintains pressure, vehicle drives as it should.
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