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Lou P.
Lou P., ASE Certified Technician
Category: Pontiac
Satisfied Customers: 4603
Experience:  I have 15+ years gm experiance and am very knowledgeable with systems and operations and diagnosis and have access to factory wiring diagrams and tsb's
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Pontiac ws6: fuel pressure used to be 60psi now 55 on rev or

Customer Question

fuel pressure used to be 60psi now 55 on rev or accelerate fuel can drop as low as 20psi. took to shop they told me it was internal fuel pump so I replaced it $300.00 later still same poblem
Submitted: 2 years ago.
Category: Pontiac
Expert:  Lou P. replied 2 years ago.
Hello my name is ***** ***** i will do my best to help you , i strive for EXCELLENT service and nothing more. What is wrong with the car ? Why are you testing fuel pressure. Let's start with that first. Lou.
Customer: replied 2 years ago.
on acceleration car starves for fuel
Customer: replied 2 years ago.
by the way my car is super charged with a procharger 740 hp at the engine
Expert:  Lou P. replied 2 years ago.
Ok yes the more information the better. So do you only have 1 fuel pump ? Is it on the tank or external ?
Expert:  Lou P. replied 2 years ago.
I'm sorry I meant IN the tank.
Customer: replied 2 years ago.
factory one in the tank and a booster one exteral provided by pro charger
Expert:  Lou P. replied 2 years ago.
Ok so where are you checking for pressure at ? The fuel rail AFTER both pumps ?
Customer: replied 2 years ago.
I have gage installed on the fuel rail after both pumps
Expert:  Lou P. replied 2 years ago.
Ok I am starting to get a picture. Alright so you replaced the tank pump yes ? Is that what you mean by internal ? This may be redundant but I want to help you for sure.
Customer: replied 2 years ago.
yes I replaced with factory recommended pump in the tank with no change
Expert:  Lou P. replied 2 years ago.
Ok thanks. I REALLY appreciate your patience , I'm sure your frustrated by now with the car , so you you run a switch for the booster pump ? Or is it key on power ? And do you work on it yourself ? I have a test you can try
Customer: replied 2 years ago.
the booster pump is key activated and I've ran the car with the booster and with out the booster no change I was told that the factory in tank fuel pump should have no problem running the system as a stand alone
Customer: replied 2 years ago.
yes I do work on the car
Expert:  Lou P. replied 2 years ago.
Ok I have not personally worked on a system like this but I'm pretty good with diagnosis so I would like you to disconnect the booster pump and jump power to it for a few seconds (make sure the polarity is correct !!) and make sure you hear it come on , also has the system ever worked correctly ? Or are you still finishing the install and this is the problem you have come across ?
Do you also have a fuel pump VOLTAGE booster on the factory fuel pump ?
Customer: replied 2 years ago.
I don't know about voltage booster on the factory fuel pump what ever that is standard with Pontiac firebirds the booster pump seems to be working
Expert:  Lou P. replied 2 years ago.
Ok and what about my second question? Had the car ever run right. ? Had this issue just started ? Or is it something you have been fighting since day 1?
Customer: replied 2 years ago.
I have about 20,000 miles on this system it's an every day driver for me everybody needs one it used to hold 60 psi always even when I was on boost.
Expert:  Lou P. replied 2 years ago.
Ok so when you start the car and let pressure stabilize , and shit the car off , how long does it hold pressure for ?
Customer: replied 2 years ago.
it freezes it till you turn car key on again
Expert:  Lou P. replied 2 years ago.
Ok so that is good. I think your issue is the booster pump. You said you ran it without it and there was no change. That tells me something is wrong. The booster pump should change the pressures and help the main pump. I am thinking the issue is with your booster pump. If you have been running the factory style pump for 20,000 miles and it was replaced and no change with another factory style and it holds presure than the only thing that makes sense is a restriction. So the only thing left is the booster pump. I would have to go with that. Process of elimination. There is not much to the fuel system. And I was thinking leaking fuel injector but the fact that it holds pressure means that there are no internal or external leaks. And from what I can find the booster pump should assist with a few extra pounds well if the pump is not correctly you pumping then it becomes a restriction. I wonder if you meant by removing the booster pump you meant disconnecting the power wires? Or physically removing it from the line. ??
Customer: replied 2 years ago.
I'll try that thanks Lou
Expert:  Lou P. replied 2 years ago.
Ok Hope this information helps , if I am wrong you can return here and we can continue. Please take a second and click the box and rate my service GOOD OR EXCELLENT SERVICE if you feel I have been helpful and please request me in the future. If you feel I have not been helpful please DO NOT RATE BAD OR POOR AND WASTE YOUR MONEY , I will opt out to see if another expert can provide more or better assistance so you're not wasting your money!!. Thanks for choosing just answer. Lou. also , if you feel i deserve one , BONUSES are GREATLY APPRECIATED ! 😉