Fuel system question

03-09-2002, 07:19 PM

While i had my 95 GT in my automechanics class shop i tested the fuel pressure and got 20 psi with KOEO. Then i got 30 psi KOER. I know the specs are 35-45 psi KOEO and 30-45 psi KOER. Would a bad regulator cause the KOEO reading? I forgot to pull the vacuum line when the engine was on to se what the pressure went up to. Also acouple times when i shut the engine off the fuel pressure would drop to 0. Sometimes it would stay at 20. Whats the deal with that? Also would 30 PSI cause a lean condition? Because thats how the car is running

03-11-2002, 04:23 PM

anybody?

95mustanggt · 03-11-2002, 04:35 PM

My car is detonating too. And I've had the fuel system suspect for a while. It just only detonates when it is hot out or when the car has been running a long time.

I don't have an answer for you though

exgmguy · 03-11-2002, 07:08 PM

My car does the same thing. It is only a problem if the fuel pressure drops to zero within seconds. The fuel can go 2 places. Past the injectors and into the cylinders, or by the regulator and back to the tank.

As far as key on, engine off fuel pressure, I would not worry too much about that. 30 psi with the engine running is normal and at WOT the pressure should rise to 38-40. You can also check WOT fuel pressure just disconnecting the vacuum line to the regulator while the engine is running.

03-12-2002, 12:45 PM

Well the pressure doesnt drop in seconds it drops instantly when i turn the key off. But it only does it once in a while. Ive found out that acouple of the injectors were replaced and the rest were ultrasonicly cleaned, so i doubt the injectors as the problem.

03-09-2002, 07:19 PM	#1
Mustang Cain Guest Posts: n/a	Fuel system question While i had my 95 GT in my automechanics class shop i tested the fuel pressure and got 20 psi with KOEO. Then i got 30 psi KOER. I know the specs are 35-45 psi KOEO and 30-45 psi KOER. Would a bad regulator cause the KOEO reading? I forgot to pull the vacuum line when the engine was on to se what the pressure went up to. Also acouple times when i shut the engine off the fuel pressure would drop to 0. Sometimes it would stay at 20. Whats the deal with that? Also would 30 PSI cause a lean condition? Because thats how the car is running

03-11-2002, 04:35 PM	#3
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	My car is detonating too. And I've had the fuel system suspect for a while. It just only detonates when it is hot out or when the car has been running a long time. I don't have an answer for you though __________________ 1995 Mustang GT 20016 F150 Lariat Super Crew

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03-11-2002, 04:23 PM	#2
Mustang Cain Guest Posts: n/a	anybody?

03-11-2002, 07:08 PM	#4
exgmguy Registered Member Join Date: Feb 1999 Location: Utica, Michigan Posts: 2,631	My car does the same thing. It is only a problem if the fuel pressure drops to zero within seconds. The fuel can go 2 places. Past the injectors and into the cylinders, or by the regulator and back to the tank. As far as key on, engine off fuel pressure, I would not worry too much about that. 30 psi with the engine running is normal and at WOT the pressure should rise to 38-40. You can also check WOT fuel pressure just disconnecting the vacuum line to the regulator while the engine is running.

03-12-2002, 12:45 PM	#5
Mustang Cain Guest Posts: n/a	Well the pressure doesnt drop in seconds it drops instantly when i turn the key off. But it only does it once in a while. Ive found out that acouple of the injectors were replaced and the rest were ultrasonicly cleaned, so i doubt the injectors as the problem.