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quick help: on my way in to the shop, what SHOULD my fuel pressure be?

Old 10-24-2009, 11:29 AM
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0949er
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Default quick help: on my way in to the shop, what SHOULD my fuel pressure be?

Bout to go to the shop to just check some more on this P0190 problem. I need my oil changed anyways, so I think i'm gonna ask them if they can change my fuel filter and check my fuel pressure as well. What SHOULD my fuel pressure read? (on a 100% working system)
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Old 10-24-2009, 01:11 PM
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39psi
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Old 10-24-2009, 02:22 PM
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40 w/o vacuum and 30 with vacuum. Unless you have cams then you need to just go off of the w/o reading.
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Old 10-24-2009, 02:58 PM
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how do you check pressure on stock rails? I do have cams, so I am looking for the w/ vacuum psi?

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Old 10-24-2009, 05:31 PM
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Originally Posted by highpsi04
40 w/o vacuum and 30 with vacuum. Unless you have cams then you need to just go off of the w/o reading.
no the fuel pressure should be steady 39psi at idle, part throttle, and wot. It doesnt matter whether you have cams or not. It may fluctuate 1-2psi but thats it
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Old 10-24-2009, 06:32 PM
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ok so how do you measure fuel pressure? What would I need in order to do it? I took it to a local shop and they said they couldn't do it because the fuel rails had no port to check pressure.
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Old 10-24-2009, 06:51 PM
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Why do you pay someone to change your oil?
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Old 10-24-2009, 07:28 PM
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Originally Posted by Frostbitten
no the fuel pressure should be steady 39psi at idle, part throttle, and wot. It doesnt matter whether you have cams or not. It may fluctuate 1-2psi but thats it
Wow do you even know what a car is? I'd like to see what your car would do if it stayed at 39psi at WOT LOL.

I'll give you that the pressure should be set at 39-40 psi without vacuum. When vacuum is connected it will read 29-30. If you have cams (real ones not stage 1) then you will read higher around 32-35 depending on the cams. WOT the pressure will raise to 43 in a NA car and around 48-... in an FI car depending on boost level.
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Old 10-24-2009, 07:28 PM
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Originally Posted by 0949er
ok so how do you measure fuel pressure? What would I need in order to do it? I took it to a local shop and they said they couldn't do it because the fuel rails had no port to check pressure.
You need to use a scanner.
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Old 10-24-2009, 08:00 PM
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Originally Posted by highpsi04
Wow do you even know what a car is? I'd like to see what your car would do if it stayed at 39psi at WOT LOL.

I'll give you that the pressure should be set at 39-40 psi without vacuum. When vacuum is connected it will read 29-30. If you have cams (real ones not stage 1) then you will read higher around 32-35 depending on the cams. WOT the pressure will raise to 43 in a NA car and around 48-... in an FI car depending on boost level.
you have no idea what your talking about. do you want to see my datalog sheet with multiple graphs of all my parameters? do you even know how to read one of those? do you even know what a returnless fuel system does?
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