fuel pressure [Archive] - GrandAmGT.com Forum


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11-06-2010, 12:15 AM
can anyone please tell me what the fuel pressure is supposed to be on a 02 grand am gt1. ive got a pressure guage on it right now that reads anywhere from 50-60 psi at idle and fluctuates from 40-60 psi while driving. aswell tryin to pass anything on the hwy is a no go seeing that the car hesitates from 2,000 rpm and up under heavy acceleration...doesnt seem to do it as bad under light to moderate though.

11-06-2010, 10:40 AM
Should be 48psi at idle, but that can fluctuate somewhat depending on how much vacuum you are pulling. With the vacuum tube off the regulator (which simulates full throttle) it should be 55psi.

11-06-2010, 09:17 PM
k cause mine as soon as i turn the key it gets between 55-60psi and remains the same when idleing. aswell when i pull the vacuum line off the regulator pressure doesnt change

11-06-2010, 09:38 PM
When you turn the key the fuel pump activates but the engine isn't running so there is no vacuum yet. It is normal atmospheric pressure which is the same as full throttle when the engine is running.

It definitely shouldn't stay like that at idle though, and it should definitely change when you open the throttle all the way or take the vacuum tube off the regulator. I'd say you probably have a faulty fuel pressure regulator.

11-06-2010, 09:52 PM
k. cause even when i revved it up with the vac line off the pressure didnt change so that would make sense...but driving the car today the service engine soon light started flashing for like 10 seconds or so and then stayed on...im assuming cause either lack of pressure or too much fuel is either causing it to misfire or screwin with the o2 sensor