Stock fuel pressure settings...
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ninety15.0
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- Mar 10, 2004
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Im just wondering because i have never messed with the fuel pressure. Can you even adjust the fuel pressure on a stock pump without a AFPR? and where is the vacuum line located and what exactly does it mean when you say vacuum on or off. thanks for the help
Should be 38 with the vacuum on, however, says my and my friend's Ford manuals.
You can't adjust a non-adjustable regulator, though.
You can't adjust a non-adjustable regulator, though.
The proper way to check is to pull the vac line off of the regulator (right on top of the non adjustable stock one) and plug the vac line (with your thumb or whatever) if you have a gage, it should read 38-39.
I've alway's seen 39.
there is no way to adjust the stock regulator, nor would you want to on a mostly stock set up.
I've alway's seen 39.
there is no way to adjust the stock regulator, nor would you want to on a mostly stock set up.
ECU5.0
Banned
alright, someone said 39 vac off and someone said 39 vac on...which one is it? im running like 34 vac on...am i running too lean?
willys1
Active Member
Jason 302
10 Year Member
Boy i tell ya what....tonight was hell. I was installing a kirban AFPR and seemed like nothing went my way. Got the wrong fitting for the guage at the local speed shop 30 mins away and then tried to make it work with a double male connector from advance auto. Ended up breaking the fitting off in the fuel rail at the shreader valve and breaking to vaccum lines. After I drilled the fitting out of the fuel rail I called it quits for the night. Gonna pick up the right fitting tomorrow. Got the AFPR installed though and it doesnt leak so thats good. All this is why I was wondering what the stock setting was. My cars running really rich so im gonna go a little lower than whats stock and hopefully get this thing to pass emissions. Whats the lowest psi you can safely run? Or if anyone has had a similar problem with running rich and then lowering the psi, what did you set it to? I won't have access to a dyno again for sometime so I'd like to have a good safe tune. BTW Air/Fuel is about ~11.5 throughout the rpm range in case you didnt see my dyno graph i posted eariler this week. Thanks
ECU5.0
Banned
its really hard to tell if you are running rich. from what ive noticed it depends on the car. ive heard stock is like 32 vac on with 10* timing. im running 10* timing with a chip and 34 vac on, 41-42 vac off. ive seen people on here running 51 vac off with a stock motor minus gears and exhaust. its hard to tell. sorry to hear about the trouble. murphys law>>if something is going to go wrong it will go wrong at the worst possible time. hope you get the car running like you want.
93tealstang
Founding Member
Stock fuel pressure is 38-39 psi. with the vaccuum off and plugged. With it on, it should be around 30 psi.
Lxpony
Founding Member
93tealstang said:
ok, the rubber vac line should be plugged when checking pressure not the metal nipple on top of the Fuel pressure regulator correct? this would be the "vacuum off" procedure right?
I finally got everything hooked up right after another trip to carolina mustangs this morning. Fuel pressure was set at 46 with vaccum off. I turned it down to 38 with it off and it dropped to 30 with the vaccum on. Ran the car and it pulls much better even with the stock h-pipe on instead of the off road one. The smell from the exhaust is also gone. I can't hear any detonation so im going to go have it inspected and then come back and check the plugs. Overall im really glad its running like it should. I dont know why it was so high before, maybe the guy who had it before me upgraded the fuel pump. Doesnt really matter though. Now I gotta get it back on the dyno and see how much power I picked up.
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