Fuel pressure

[DeckerEnt]

I finally started my coupe last night. I put a walbro 255 pump in the tank and noticed on the guage that I now have a little over 60 lbs of fuel pressure. I know I can take an allen wrench and adjust it at the back of the fuel rail. What pressure should I run?

[fordfan]

I think around 35 with the vacuum line off.

[Jeff88coupe]

38-40psi is the stock range.

[DeckerEnt]

OK. New question. My fuel pump doesn't shut off. It reaches 60 psi and keeps it from when I turn on the key through idle. As soon as I burp the throttle, the pressure drops to around 40 psi but then goes right back to 60. I wired the relay under the driver's seat to the e-brake sensor wire. The wire from the puter only showed 6.5 volts and wouldn't activate the relay. The adjustment on the fuel rail doesn't bring the pressure down. I have screwed it all the way out and all the way in with no change in pressure at the guage. Any ideas?? Thanks...

[quik lx]

What regulator you running? I had a Holley brand one that would'nt adjust once. And just to be sure...... make sure the fuel gauge is before the regulator in the system.

[DeckerEnt]

Actually it is a stock fuel rail and the stock regulater.

[soslow]

you need an adj fuel pressure reg maybe that might fix your prob ..

[DeckerEnt]

I found another fuel rail in my pile of parts. It has the same stock regulater on it that I have on mine. I am going to pull the upper off the car and replace my regulater with this one. See if that lets me adjust the pressure. If this doesn't work, looks like I need an adjustable regulater. Any one got one laying around?

[DeckerEnt]

OK. Put the other regulater on and the pressure went to 80. And it leaked so off it came and the old one went back on. I adjusted it backing the screw all the way out and it dropped from 64 to 60 so I guess I need a new one. Darn it.

[Gearhead]

Keith,

Ok, I think I'm confused, I thought the stock fuel pressure regulator was non-adjustable ??

I think I have an extra Kirban adjustable FPR if you want to try it...

[quik lx]

[QUOTE=Gearhead;468944]Keith,

Ok, I think I'm confused, I thought the stock fuel pressure regulator was non-adjustable ??[QUOTE]

The stock ones arent adjustable, I think they are set around 39 PSI at full vac?

[DeckerEnt]

I am going to take pics of everything I have so you all know what I am talking about. I will post them on my myspace page. Give me a few, need to eat lunch.
Basically I have 2 fuel rails. Both have the same regulater on them at the back passenger side of the rail. My guage is on the high pressure side of the hard line coming from the framerail to the fuel rail. I have a walbro 255 in tank pump. The pump puts out 60 psi as it sits and runs constantly.

[Rick93coupe]

The stock regulator is not adjustable. Its got 3 retaining bolts that hold it down and that it. An adjustable that sits on the stock rails has a screw coming out of the middle of it that you can adjust after taking off the vaccum line.

[mustang8998]

make sure the fuel gauge is before the regulator in the system.

That doesn't make sense, to me. If it is before the regulator, it would show full pressure all the time. After the regulator, it would be regulated down.

The reason I say this, is when I had EFI in mine, I plumbed it in rail at the bleeder. Worked just fine.

[Rick93coupe]

That doesn't make sense, to me. If it is before the regulator, it would show full pressure all the time. After the regulator, it would be regulated down.

The reason I say this, is when I had EFI in mine, I plumbed it in rail at the bleeder. Worked just fine.

In a factory setup the bleeder for the system is where you put the gauge.

[DeckerEnt]

Pics are on my myspace. www.myspace.com/keithdecker
Go to my pics page.
It seems I have 2 adjustable regulaters. Strange that they are the same from 2 different cars and different years. Mine has the three allen head bolts. Jon may give me a stocker from his lincoln to try. That should get me down to 38-40. Hopefully that will help.

[quik lx]

That doesn't make sense, to me. If it is before the regulator, it would show full pressure all the time. After the regulator, it would be regulated down.

The reason I say this, is when I had EFI in mine, I plumbed it in rail at the bleeder. Worked just fine.

Hey Jeff, I just learned all this recently.....on fuel injection the regulator regulates fuel pressure before it (therfore balancing the injectors) by bypassing fuel after it, so the pressure gauge needs to be before it just like the injectors. If you checked your stock set-up the bleeder is in the feed line before the regulator. On carb applications the regulator regulates fuel after it by bypassing a determined amount of fuel. Check out Aeromotives web site, it helped me out alot when I planned out the system for my mod swap.

[Jeff88coupe]

Pics are on my myspace. www.myspace.com/keithdecker
Go to my pics page.
It seems I have 2 adjustable regulaters. Strange that they are the same from 2 different cars and different years. Mine has the three allen head bolts. Jon may give me a stocker from his lincoln to try. That should get me down to 38-40. Hopefully that will help.


I do believe that you have 2 of the old holley AFR...those are junk. I'd try to find a kirban one if you want an AFR. A stock one should work just fine for ya.

[mustangjon]

I gave him my functioning old one to try. We'll see if that fixes his problem. Like i told him pump running all the time or not shouldnt matter the pressure since our systems are open looped back to tank

[DeckerEnt]

Tired of messing with it tonight. Gonna swap yours on tomorrow after work. Thanks Jon!

[DeckerEnt]

Well, after dicking with this thing for a few days, I found the problem. I disconnected the return hose at the frame and put a hose on the hard line. Ran the hose to a bucket and turned on the pump. The fuel flowed fine and the guage read 42 psi. My return line from the frame to the tank is clogged somewhere. The flexible part from the frame to the motor looks twisted a little but not collapsed. I think I will just get some small fuel line and run another return line to the tank. More later.

[mustang8998]

Hey Jeff, I just learned all this recently.....on fuel injection the regulator regulates fuel pressure before it (therfore balancing the injectors) by bypassing fuel after it, so the pressure gauge needs to be before it just like the injectors. If you checked your stock set-up the bleeder is in the feed line before the regulator. On carb applications the regulator regulates fuel after it by bypassing a determined amount of fuel. Check out Aeromotives web site, it helped me out alot when I planned out the system for my mod swap.

Ah, I see what your saying.

Guess I was looking at it, as reverse flow (pump, regulator, injectors).

Thanks for straightening me out on that Joe! :bigthumb

[mustang8998]

Keith, I wish I had removed all my old lines more carefully. I wasn't thinking that either of them, could be of use, to someone.

[DeckerEnt]

No problem Jeff. My fault for storing them outside behind the shop for a while. I got it figured out now.

[DeckerEnt]

My problem is solved. I cut the plastic line at the motor and found a barbed end. I got 5/16 inch fuel line and just ran it from the motor to the tank. Turned on the pump and the guage reads 40 psi. Done. On to other things. Thanks all for the help!!!

[quik lx]

Nice!!! Now finish it so you can drive it!!!!:cool1:

[DeckerEnt]

Working on getting tags for it now!!!