94NDTA

I'm currently trying to figure out a fueling issue with my car. I have been back and forth with Solomon about my tune.

One of the particulars who has asked me about is fuel pressure. Stock FPR, Walbro 255 pump. Racetronix 37# injectors. (Basic LE2 set up with supporting mods)

When I prime the pump, it's at 42.5 psi. When I start the car, it reads 48 psi with the vacuum hose attached. When I disconnect it, it goes to 53 psi.When I shut the car off, it drops back to 39-40 psi.

If I let it sit, car off, it will gradually climb from 39-40 psi, and will eventually hit 49-50 psi after about 10 minutes or so of being shut off.

My understanding is it needs to be around 43.5 psi with the vacuum removed.

Currently it is tuned for 53 psi, but we are working out some particulars with the injectors (I did not provide him with the correct information originally).

Should I be concerned it is higher than normal?

I have heard of restrictions in the return line causing the pressure to run higher, maybe the charcoal canister, or the gas tank vent I have been meaning to replace (gas tank has a ton a of pressure when I open the tank, plus I can tell it is fading my rear white bumper)

BALLSS

IDK why you need a tune with 53 PSI of FP

For whatever reason your tuner says you do you would need a adjustable FPR as a "stock" one should be giving you about 43.5 PSI with vac line off, not 53 so your stock FPR would be bad if you are getting FP that high

94NDTA

Maybe I phrased this wrong. Solomon is doing a tune for my H/C set up, one of his questions was my fuel pressure. He is not requesting that I have 53 psi of fuel pressure with his tune, I HAVE 53 psi of fuel pressure with my stock FPR. His last tune he sent me was with this in mind. This sparked my concern that my FP is too high.

Before I simply blame it on the FPS, my question is there anything else than can cause my fuel pressure raise? Anything else I should look at that may be causing this?

BALLSS

The fuel pressure "regulator" is what controls FP....if you have 53 PSI (assuming your gauge is right) from a stock FPR...the FPR is bad

Surprised any tuner would work with 53 vs saying "fix your FP issue"

I have a adjustable FPR, BWD, that I set at 43.5 PSI with vac line off. A stock FPR should give you that

94NDTA

I guess I haven't heard of too many failing and he fuel pressure being too high, wanted to make sure it couldn't be anything else before I replaced it.

BALLSS

if you pull the vacuum nipple off after shutting off the motor and there is evidence of fuel in it, FPR is bad

Generally that type of failure makes for a prolonged start. Not necessarily high FP

Several running the 255 lph Walbro with stock FPR without issues

The FPR purpose is to "regulate" FP to the spec for that regulator. 53 PSI is to high and I would suspect you are running pig rich as a result unless your tuner has adjusted for that high of FP. Weird he would though without saying to fix your FP issue

94NDTA

The FPR does not leak. I've checked it multiple times. It also holds pressure for a long time after the car is off.

He does have the tune adjusted for that high of FP. Solomon said it happens all the time where aftermarket pumps over power stock FPR.

Either way, I ordered another fuel pressure gauge to see if it reads the same and go from there.

The main point of this thread was to try and determine if anything else can raise fuel pressure besides FPR.

BALLSS

Just not heard of people who did put in a 255 with a stock regulator got higher than stock fuel pressure. I didn't when I put my 255 in several years ago. I get the idea that a larger flowing pump would send more fuel to FPR...but thought if the FPR is set to regulate the pressure at about 43.5, it would do that. Your situation seems to indicate more feed from a larger fuel pump increases FP on the output side of the FPR

If your tuner can work with it and your larger injectors fine

My tuner said my FP should be 43.5 without Vac line attached for the tune he did. 383 H/C with 30lb Ford SVO injectors and a 255 lph pump

Nostang

iTrader: (4)

Did you double check to make sure it is not the FP gauge giving a false reading?

94NDTA

I've got a new gauge on order (I borrowed one, I should have one of my own anyways).

I also have a new FPR on order, if it is still high, I will replace and see if it changes. I will report back in a week or two.

BALLSS

If you do find the pressure is high with a stock FPR you can get a adjustable. I have a BWD (Borg Warner) adjustable FPR. It is the same size/shape as stock so it is plug & play install. It was about $55 IIRC. I got it at a local auto part store

BWD-23065

Agree you should have a fuel pressure gauge. One with a hose on it so you can tape the gauge to windshield. Good if you want to see if FP holds while under "sustained" WOT conditions.

I bought a Hypertech one several years ago that is Schrader valve attachable

transbird95

iTrader: (4)

I had a fpr read high almost just like yours last year. Put a new one in and it went right back to 43lbs.

94NDTA

Good to know. If this one reads high with the new gauge, I will swap in a new delco unit and have Solomon adjust the tune. If it's failing, I would much rather have the tune set up with a properly working FPR.

94NDTA

Well, new gauge reads fuel pressure right at 43.5 psi with vacuum line removed.

I wouldn't have guessed the gauge. I'm kinda shocked, I guess I will return the FPR. New tune incoming, I see good things in the future.

96lt1m6

iTrader: (31)

Good deal man.

Casey96SS

Maybe the new gauge is bad and the old one is right?

Just kidding.

Mine reads high too even after a new AC Delco FPR. I guess I will see if I can test my gauge out somehow.

94NDTA

Don't do that! I already thought of that. But he fact that I was having fueling issues and that the tune with my PSI set at 53 has been giving me issues, I'm going to bank on my new one working and the old one not working.