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fuel pressure dropping below 10 psi when accelerating help please.

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fuel pressure dropping below 10 psi when accelerating help please.

Old 07-23-2009, 03:31 PM
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kennebellgt
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Default fuel pressure dropping below 10 psi when accelerating help please.

I have a 95 gt 5.0, I am having a huge problem of my car bogging out and sputtering, i hooked up a fuel pressure gauge so i can see what the fuel pressure does when driving, and once the car warms up and only when it warms up the car bogs severely to where i can barely hit the gas to go anywhere, i have to barely press on the gas for it to move without bogging anyways, I was looking at the fuel pressure gauge while i was driving and it drops below 10 psi maybe almost to 5psi or below it all depends on how much i hit the gas, if i barely hit the gas the fuel pressure goes up but if i hit it hard it drops anywhere between 20 psi - 5 psi or below depending on how much i hit the gas, and when it drops down like it does it sputters, pops, and bogs out really bad. also when it bogs out like it does i can shut the car off then start it back up immediately and the problem is gone it doesn't bog out at all then about a mile later it starts to run like crap again, any insight would be greatly appreciated, Thank you.

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Old 07-23-2009, 04:00 PM
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when you shut the motor off do you lose pressure immediately?
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Old 07-23-2009, 04:05 PM
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Originally Posted by FivePointOhh View Post
when you shut the motor off do you lose pressure immediately?
yes..
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Old 07-23-2009, 04:10 PM
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go to the rear of your car. find your return line of your fuel lines(the one not going through the fuel filter) and pinch off the rubber part of the return line with small vice grips or something very gently.

turn your car on for a second or so and turn it back off and watch the gauge. does it still drop to 0 immediately??
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Old 07-23-2009, 04:12 PM
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Originally Posted by FivePointOhh View Post
go to the rear of your car. find your return line of your fuel lines(the one not going through the fuel filter) and pinch off the rubber part of the return line with small vice grips or something very gently.

turn your car on for a second or so and turn it back off and watch the gauge. does it still drop to 0 immediately??
okay hold on give me a min or two ill do it now
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Old 07-23-2009, 04:17 PM
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Originally Posted by FivePointOhh View Post
go to the rear of your car. find your return line of your fuel lines(the one not going through the fuel filter) and pinch off the rubber part of the return line with small vice grips or something very gently.

turn your car on for a second or so and turn it back off and watch the gauge. does it still drop to 0 immediately??
yes it still drops to 0 immediately. i started the car let it run for about 10 seconds and shut it off and it dropped immediately, i started it back up the shut it off and it did the same thing dropped right away.
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Old 07-23-2009, 05:39 PM
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you have a leak in your fuel system somewhere. how old is the bbk fpr?
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Old 07-23-2009, 06:31 PM
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if there no external leaks here are some things that could cause it, restricted fuel filter= causes drop in fuel pressure while under acceleration due to insufficient volume....leak down in koeo mode often will only cause a brief extended crank period before fire up, so I wouldn't be so concerned with that issue yet, the pump may also be bad and or voltage drop to the pump occuring, when pump is removed inspect all connector pins for overheating if none exist replace pump and sock on end of pump and new fuel filter and retest
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Old 07-23-2009, 08:46 PM
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Originally Posted by FivePointOhh View Post
you have a leak in your fuel system somewhere. how old is the bbk fpr?
yeah i just replaced the fuel filter, and the regulator is about a year old.
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Old 07-23-2009, 08:52 PM
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Originally Posted by mjr46 View Post
if there no external leaks here are some things that could cause it, restricted fuel filter= causes drop in fuel pressure while under acceleration due to insufficient volume....leak down in koeo mode often will only cause a brief extended crank period before fire up, so I wouldn't be so concerned with that issue yet, the pump may also be bad and or voltage drop to the pump occuring, when pump is removed inspect all connector pins for overheating if none exist replace pump and sock on end of pump and new fuel filter and retest
thats what i'll do thanks for the help guys, I'll report back within a few days.
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