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Pontiac Repair/fuel pump is pumping but car not starting


QUESTION: You have answered several questions on our 1990 pontiac grand prix and have been right on the money so now I have one on a 2002 pontiac grand prix 4 cyl. We have replaced 3 fuel pumps on this car and it runs for a little while and does the same thing. It is pumping gas and turns over but just won't start. Could it be the fuel pressure regulator or sensor or are these the same thing? It is pumping fuel. If it is could you tell us where it is located? This is for my daughter in law that has 2 babies and needs her car for work. Thank you so much.

ANSWER: Hi trudy:

well first off you need to determine if it had pressure. just because the pump runs doesn't mean it has enough pressure to run and orvolume to keep the engine running. This is a odd bird. Not many grand Prix's with a 4 cylinder out there must have been a rental car at first. have you replaced the fuel pump with the correct part first off being that it's a 4 cylinder I'm sure the pump is different then the V6 engines. I would only use an AC delco pump. The pressure on that engine should be between 40-45 PSI I would "guess" if it far less then that it will not run. If it has correct pressure then next move would be to check for injetor pulse and spark. You need a spark checker and noid light for the injetors. check for spark on these engines is challenging because the coils are on the top of the engine and they care paied 2 2 culinder on each coil. you can take the cover off the top of the engine pull the plug boots off and then hold the coil assembly on the engine so the tips of the coil connectors are about 1/4" off the engine evenly and have someone crank the engine you should see the spark jumping from the coils to the engine. That is where I would start looking....

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QUESTION: I am sorry. It is a Grand Am not Grand prix. I am so sorry. It pumps but it does not have enough pressure to make it run. We were told it could be fuel pressure regulator. All of the other things you mentioned are ok. I am sorry for the mistake. Been a long week.

Yes it could be a fuel pressure regulator. what is the pressure it has or should I say doesn't have? the model of cart doesn't matter much an engine still need the same things to run. one other thing to lok at would be a fuel pump replay. If the relay has a bad set of contatcts in it it could cause increase resistance in the power feed to the pump and make it run slower then it should which = lower pressure. the fule pump replay in in the under hood fuse block take a look at that the underside of the box cover has the road map for the fuses and relays find the fuel pump relay and swap it out with another one in the box with the same part# stamped on it. The fuel pump one may be unique and have 5 pins and you will not find another one in the box with the same part #. Not sure on that I'm not a parts guy...  

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Todd Puccio


General auto repair,electrical issues,driveability issues,anti-lock brakes,SIR systems,HVAC,engine performance,Gm specific. I have worked at my current dealership since the 1990 model year anything much older than that I have limited exposure to. I do not have very much transmission experience so those question you may want to ask of another expert. When you send me a question let me know the exact make/model/engine and year for the car or suv you have it makes it easier to answer the questions that way. If your happy with the answer I gave you please feel free to Donate. This is a free service to you and I am not compensated at all by this web site. I have 22 years of experience to share with you and my knowledge wasn't free to me. I had to pay for my education.


Experience in the area: I have been a technician in GM dealerships for over 22 years and I am a ASE master technician. I work at a Buick and GMC truck store Previously I worked at a Pontiac GMC store for 18 years. I Served a a lead technician when dealership was on a team system. I just recently moved to a Buick,Hummer,Saab Store when my franchise was purchased by this dealership. Organizations: ASE master technician


Education/Credentials:High school diploma,2 year vocational school degree 2 year college degree. Associates degree in applied sciences (auto technology)Awards and Honors: GMC master technician

Awards and Honors
Master GMC truck technician Master ASE technician in 9 categories

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