Would AFPR fix this?

Lethal5Oh · 06-16-2002, 09:29 PM

My 95 GT is running lean (according to a snap on scanner) Fuel test shows 30 PSI (which drops to nothing when the engine is shut off) Would putting on a AFPR and cranking it up to say 35 or maybe alittle more richen it up or am i looking a something else here. Plugs are bone white (except when i put in octane booster, they turn red)

Dark_5.0 · 06-16-2002, 09:33 PM

I think you either have a weak fuel pump or a clogged fuel filter. You can run almost 300HP with the stock fuel pressure.

Later.

06-16-2002, 09:43 PM

You should have 39 psi, my first thought is fuel pump as well.. for some reason it isn't getting the fuel pressure it should be getting.

jimberg · 06-16-2002, 09:47 PM

If you're only showing 30 psi then you need to replace your FPR. It should be 39 psi. A/F ratio is controlled by the computer, not the FPR. You can replace it with an AFPR if what want, they aren't much more than a stock replacement. Set it at 39 psi when you get it installed, though.

jimberg · 06-16-2002, 09:50 PM

Since your regulator leaks down immediately, I would suspect that first. It's an easier, cheaper fix, too. It could very well be the fuel pump as the others suggest. It could be bad to the point that fuel can leak back through it.

Lethal5Oh · 06-16-2002, 11:44 PM

I know its not the fuel filter, i just replaced it. I should have given more info on the reg. During testing i shut the car off and turned it on a few time. On ocasion the fuel pressure would drop to 20 when the car was turned off, but most of the time it drops to nothing. I can tell when pressure has been held because sometimes the car starts on the first crank but if the pressure is gone it can take 3-5 cranks or more to start it. ITs worse when its cold out (below 50) If the pressure is below the normal wouldnt that cause a lean condition?

06-16-2002, 09:29 PM	#1
Lethal5Oh Registered Member Join Date: Jun 2002 Location: Portage Posts: 239	Would AFPR fix this? My 95 GT is running lean (according to a snap on scanner) Fuel test shows 30 PSI (which drops to nothing when the engine is shut off) Would putting on a AFPR and cranking it up to say 35 or maybe alittle more richen it up or am i looking a something else here. Plugs are bone white (except when i put in octane booster, they turn red) __________________ '95 GT convert. K&N, C&L mass air meter, Performance distributors sreamin demon coil, dyna mod, live wires, king cobra clutch, flowmaster american thunder exhaust, UPR billet adjustable shift handle, Crane Cams Fireball HI-6 box,underdrive pullies, 255lph fuel pump, UPr short throw shifter, caster camber plates, 03 cobra lower A arms, bullit suspension, cobra front brakes

06-16-2002, 09:33 PM	#2
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I think you either have a weak fuel pump or a clogged fuel filter. You can run almost 300HP with the stock fuel pressure. Later. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

06-16-2002, 09:47 PM	#4
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	If you're only showing 30 psi then you need to replace your FPR. It should be 39 psi. A/F ratio is controlled by the computer, not the FPR. You can replace it with an AFPR if what want, they aren't much more than a stock replacement. Set it at 39 psi when you get it installed, though. __________________ 351W 89 Mustang GT Convertible

06-16-2002, 09:50 PM	#5
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Since your regulator leaks down immediately, I would suspect that first. It's an easier, cheaper fix, too. It could very well be the fuel pump as the others suggest. It could be bad to the point that fuel can leak back through it. __________________ 351W 89 Mustang GT Convertible

06-16-2002, 11:44 PM	#6
Lethal5Oh Registered Member Join Date: Jun 2002 Location: Portage Posts: 239	I know its not the fuel filter, i just replaced it. I should have given more info on the reg. During testing i shut the car off and turned it on a few time. On ocasion the fuel pressure would drop to 20 when the car was turned off, but most of the time it drops to nothing. I can tell when pressure has been held because sometimes the car starts on the first crank but if the pressure is gone it can take 3-5 cranks or more to start it. ITs worse when its cold out (below 50) If the pressure is below the normal wouldnt that cause a lean condition? __________________ '95 GT convert. K&N, C&L mass air meter, Performance distributors sreamin demon coil, dyna mod, live wires, king cobra clutch, flowmaster american thunder exhaust, UPR billet adjustable shift handle, Crane Cams Fireball HI-6 box,underdrive pullies, 255lph fuel pump, UPr short throw shifter, caster camber plates, 03 cobra lower A arms, bullit suspension, cobra front brakes Last edited by Lethal5Oh; 06-16-2002 at 11:50 PM..

06-16-2002, 09:43 PM	#3
rbatson Guest Posts: n/a	You should have 39 psi, my first thought is fuel pump as well.. for some reason it isn't getting the fuel pressure it should be getting.

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