Fuel pressure problems

toevil1 · 07-13-2005, 05:46 PM

I had a shop install a 255lph fuel pump last month. Last week I noticed that my fuel pressure gauge was pegged at 60 psi. I tried messing with my fuel regulator with no change in pressure. I thought I had a bad gauge so I replaced it. Unfortunately, no luck. The weird thing is that when I give it gas, the pressure drops and then rises to 60psi at idle. The pressure is at 20 - 30 psi, engine off.

Could there be a crossed wire with the fuel pump installation or some other fuel line related issue causing this problem?

This is the first time I have had any problems with my fuel.

pearlgt40 306 · 07-13-2005, 06:28 PM

what do you have done to your car.....thats alot of fuel pump. I guess its all right anyway though since it will keep the fuel and pump cooler. What kind of regulator do you have. 60 is ridiculously high at idle. id go after the regulator since its easy. i dont know if you have a nice mechanical fuel pressure gauge or not. might wanna get one.

Hammer · 07-13-2005, 09:26 PM

I don't know what I would do without my mechanical FP guage...

Helped a lot of issues while messing with the new 306...

~The Jester~ · 07-13-2005, 10:18 PM

Regulator is suspect.

Electric gauges are for Hondas, put a real Autometer gauge on that puppy.

toevil1 · 07-14-2005, 01:53 AM

Here is a quick run down of my combination.

89 5.0 with Novi 1000 8-10lbs of boost. Not sure of boost yet because of fuel prob.
42lb inj. ( no FMU )
Holley intake
AFR 165 heads
E-cam
Aeromotive billet fuel reg.
BBK mech. fuel pressure gauge.
Stock bottom end with 100,000 miles.

I switched to the 255lph pump with 42lb inj. so that I could eliminate my FMU while maxing out the Novi 1000. It's putting out about 420fwhp right now. I made the fuel upgrades so that I could support 500+fwhp without an FMU. It put down 355rwhp on a mild tune with 5- 6 lbs of boost and the wrong FMU calibration. I will be happy with 400rwhp as soon as I figure out my fuel problem.

~The Jester~ · 07-14-2005, 09:33 AM

How was your fuel pressure BEFORE the upgrade? Are we still talking about the stock fuel lines as well? What fuel pressure are you trying to achieve?

Jeff Chambers · 07-14-2005, 11:47 AM

Make sure they didn't pinch the return line when they installed the pump. Real easy to do when you put the tank back in place and if it's pinched it'll restrict the return flow causing higher pressure on the supply side.

toevil1 · 07-14-2005, 09:54 PM

I have changed my fuel gauge and fuel regulator with no luck.

I am beginning to think it is my stock fuel lines. I ran them with a 190lph and 24lb injectors with no problem. 255lph is a big jump in volume. I will be changing them next.

The fuel pressure should be around 38 - 40 lbs

Lethal5Oh · 07-15-2005, 08:24 AM

I highly doubt your stock lines are the problem. Unless like Jeff chambers said that they pinched off the return line when reinstalling the tank. Im running a 255 lph fuel pump with the stock fuel pressure regulator and im still at 38-40 psi. Id start with checking those lines back by the tank. Good luck

toevil1 · 07-15-2005, 02:02 PM

I found the problem. I decided to try a 3rd fuel regulator. That solved the problem. Apparently the 2nd (used) regulator was no good and when I took my Aeromotive reg. apart. I found the problem. Apparently it was caused by metal shavings bundled into a little ball, that were never cleaned from the factory. It is only 3 months old.

My fuel pressure is back to normal now. Thanks for all the help, everyone.

07-13-2005, 05:46 PM	#1
toevil1 Registered Member Join Date: Sep 2002 Location: Los Angeles Posts: 39	Fuel pressure problems I had a shop install a 255lph fuel pump last month. Last week I noticed that my fuel pressure gauge was pegged at 60 psi. I tried messing with my fuel regulator with no change in pressure. I thought I had a bad gauge so I replaced it. Unfortunately, no luck. The weird thing is that when I give it gas, the pressure drops and then rises to 60psi at idle. The pressure is at 20 - 30 psi, engine off. Could there be a crossed wire with the fuel pump installation or some other fuel line related issue causing this problem? This is the first time I have had any problems with my fuel.

07-13-2005, 06:28 PM	#2
pearlgt40 306 Registered Member Join Date: May 2002 Location: Long Island, NY Posts: 14	Re: Fuel pressure problems what do you have done to your car.....thats alot of fuel pump. I guess its all right anyway though since it will keep the fuel and pump cooler. What kind of regulator do you have. 60 is ridiculously high at idle. id go after the regulator since its easy. i dont know if you have a nice mechanical fuel pressure gauge or not. might wanna get one. __________________ 306 Short Block, Forged Pistons, GT-40 Irons, Ford Racing 1.6 Ratio Rockers, GT-40 Upper and Lower Intake, B-303 Cam, 24 lb Injectors, 70 MM Throttle Body, 75 mm MAF, MAC Cold Air Intake(in fender), March Ram Air Scoop, MAC Longtubes, Offroad H-Pipe 2.5", No Cats, 40 Series Flows, 2.73's(eek...), Kenny Brown Subframes, World Class T-5, Pro 5-0 Tower Shifter

07-13-2005, 09:26 PM	#3
Hammer AKA "Dr. Evil" Join Date: Feb 1999 Location: South Fork Ranch Posts: 1,721	Re: Fuel pressure problems I don't know what I would do without my mechanical FP guage... Helped a lot of issues while messing with the new 306... __________________ Uncle Sam "What the hell is up with all the gauges? Calling Captain Kirk, your ride awaits... Phasers on stun...."

07-13-2005, 10:18 PM	#4
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Fuel pressure problems Regulator is suspect. Electric gauges are for Hondas, put a real Autometer gauge on that puppy. __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

07-14-2005, 01:53 AM	#5
toevil1 Registered Member Join Date: Sep 2002 Location: Los Angeles Posts: 39	Re: Fuel pressure problems Here is a quick run down of my combination. 89 5.0 with Novi 1000 8-10lbs of boost. Not sure of boost yet because of fuel prob. 42lb inj. ( no FMU ) Holley intake AFR 165 heads E-cam Aeromotive billet fuel reg. BBK mech. fuel pressure gauge. Stock bottom end with 100,000 miles. I switched to the 255lph pump with 42lb inj. so that I could eliminate my FMU while maxing out the Novi 1000. It's putting out about 420fwhp right now. I made the fuel upgrades so that I could support 500+fwhp without an FMU. It put down 355rwhp on a mild tune with 5- 6 lbs of boost and the wrong FMU calibration. I will be happy with 400rwhp as soon as I figure out my fuel problem.

07-14-2005, 09:33 AM	#6
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Fuel pressure problems How was your fuel pressure BEFORE the upgrade? Are we still talking about the stock fuel lines as well? What fuel pressure are you trying to achieve? __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

07-14-2005, 11:47 AM	#7
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	Re: Fuel pressure problems Make sure they didn't pinch the return line when they installed the pump. Real easy to do when you put the tank back in place and if it's pinched it'll restrict the return flow causing higher pressure on the supply side. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

07-14-2005, 09:54 PM	#8
toevil1 Registered Member Join Date: Sep 2002 Location: Los Angeles Posts: 39	Re: Fuel pressure problems I have changed my fuel gauge and fuel regulator with no luck. I am beginning to think it is my stock fuel lines. I ran them with a 190lph and 24lb injectors with no problem. 255lph is a big jump in volume. I will be changing them next. The fuel pressure should be around 38 - 40 lbs

07-15-2005, 08:24 AM	#9
Lethal5Oh Registered Member Join Date: Jun 2002 Location: Portage Posts: 239	Re: Fuel pressure problems I highly doubt your stock lines are the problem. Unless like Jeff chambers said that they pinched off the return line when reinstalling the tank. Im running a 255 lph fuel pump with the stock fuel pressure regulator and im still at 38-40 psi. Id start with checking those lines back by the tank. Good luck __________________ '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

07-15-2005, 02:02 PM	#10
toevil1 Registered Member Join Date: Sep 2002 Location: Los Angeles Posts: 39	Re: Fuel pressure problems I found the problem. I decided to try a 3rd fuel regulator. That solved the problem. Apparently the 2nd (used) regulator was no good and when I took my Aeromotive reg. apart. I found the problem. Apparently it was caused by metal shavings bundled into a little ball, that were never cleaned from the factory. It is only 3 months old. My fuel pressure is back to normal now. Thanks for all the help, everyone.

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