PKRWUD: Fuel Pressue Test Results ??

95mustanggt · 07-16-2002, 06:34 PM

Chris,

Here are the results of my Fuel Pressure Test:

I performed 2 tests

1st Test:

Fuel pressure with Key on Engine Off: 21 psi
@ idle 31 psi
After 5 minutes 29 psi

2nd Test:

Fuel pressure with Key on Engine Off: 20 psi
@ idle 32 psi
After 5 minutes 25 psi
@idle with Vacuum hose detached: 31 psi

I noticed no change when I removed the vacuum hose. I checked the vacuum hoses and these is plenty of vacuum. When I disconnected the hose although there was no change in fuel pressure, the car started to idle rough. Once I put the vacuum hose back the car ran well, but still no change in fuel pressure.

Help?!

PKRWUD · 07-16-2002, 06:41 PM

You need a new regulator. Your idle changed because you created a vacuum leak. That is normal. The pressure should have gone up at least 5 psi when you disconnected the vacuum line. Replace the regulator.

Take care,
-Chris

95mustanggt · 07-16-2002, 06:44 PM

WOW, that is quick service! Thanks for the quick response Chris!

I assume that this would also explain some detonation?

I'll replace it and hope all my problems are gone.

Cam

PKRWUD · 07-16-2002, 06:46 PM

It would explain your detonation. You are running lean above idle.

Take care,
-Chris

95mustanggt · 07-16-2002, 07:24 PM

Would this cause fuel in my oil or high oil pressure?

PKRWUD · 07-16-2002, 07:41 PM

No, but if the regulator is bad, which it is, there's no telling what else it may have done.

Take care,
-Chris

95mustanggt · 07-16-2002, 08:53 PM

Quote:

Originally posted by PKRWUD
No, but if the regulator is bad, which it is, there's no telling what else it may have done.

Take care,
-Chris

It never does get simple does it?

PKRWUD · 07-16-2002, 10:22 PM

Quote:

Originally posted by 95mustanggt

It never does get simple does it?

Sure it does. Replace your regulator. Simple.

Take care,
-Chris

BilLster · 07-17-2002, 01:11 AM

low fuel pressure can also cause your injectors to go static the computer tries to hold them open longer to compensate for the reduced pressure and when the cycles is more than 80% whamo they can just keep squirting. I had the opisite occur when i tried to run under injected and chashed an injector leak for weeks and when i replace the injectors with new bigger units and dropped fuel pressure it whent away a friend has my old injectors and at resonable levels of pressue he hasnt had a problem.

07-16-2002, 06:34 PM	#1
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	PKRWUD: Fuel Pressue Test Results ?? Chris, Here are the results of my Fuel Pressure Test: I performed 2 tests 1st Test: Fuel pressure with Key on Engine Off: 21 psi @ idle 31 psi After 5 minutes 29 psi 2nd Test: Fuel pressure with Key on Engine Off: 20 psi @ idle 32 psi After 5 minutes 25 psi @idle with Vacuum hose detached: 31 psi I noticed no change when I removed the vacuum hose. I checked the vacuum hoses and these is plenty of vacuum. When I disconnected the hose although there was no change in fuel pressure, the car started to idle rough. Once I put the vacuum hose back the car ran well, but still no change in fuel pressure. Help?! __________________ 1995 Mustang GT 20016 F150 Lariat Super Crew

07-16-2002, 06:41 PM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	You need a new regulator. Your idle changed because you created a vacuum leak. That is normal. The pressure should have gone up at least 5 psi when you disconnected the vacuum line. Replace the regulator. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-16-2002, 06:44 PM	#3
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	WOW, that is quick service! Thanks for the quick response Chris! I assume that this would also explain some detonation? I'll replace it and hope all my problems are gone. Cam __________________ 1995 Mustang GT 20016 F150 Lariat Super Crew

07-16-2002, 06:46 PM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	It would explain your detonation. You are running lean above idle. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-16-2002, 07:24 PM	#5
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	Would this cause fuel in my oil or high oil pressure? __________________ 1995 Mustang GT 20016 F150 Lariat Super Crew

07-16-2002, 07:41 PM	#6
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	No, but if the regulator is bad, which it is, there's no telling what else it may have done. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-17-2002, 01:11 AM	#9
BilLster Registered Member Join Date: Oct 2000 Location: Ontario canada Posts: 446	low fuel pressure can also cause your injectors to go static the computer tries to hold them open longer to compensate for the reduced pressure and when the cycles is more than 80% whamo they can just keep squirting. I had the opisite occur when i tried to run under injected and chashed an injector leak for weeks and when i replace the injectors with new bigger units and dropped fuel pressure it whent away a friend has my old injectors and at resonable levels of pressue he hasnt had a problem. __________________ 89 with 331 t3'/t4 hybrids. upr Suspention worked out finnaly . 9.89 144 mph .

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