my car stock is a 305TPI 89' formula, i kept EVERYTHING and basically swapped in a 350 flat tappet short block, injectors and tuned the computer.

this is my "problem", i installed the HOLLEY AFPR, and i have the adjuster tightened ALL the way down, and the HIGHEST my pressure will go is not even 40 PSI.

i need to know if this is a problem, keep in mind the diaphragm is BRAND new and NOT BROKEN.

my fuel pump i have also changed recently, it is also a HOLLEY 255 LPH pump straight from summit along with the regulator.....

any ideas???

 

Recheck your afpr agian someone else had a problem like yours with the holley

 

ugh i really dont feel like ripping taht thing off again haha...... what happened to the other guy?

 

You might try changing the screw that they gave you with a longer screw. Might also need a replacement. You can get by with 40psi, lower rpm drivability will suffer though, you might notice it start to jerk at lower speeds with a lower psi.

 

I think the other guy put a bbk on his and was fine after that.I my self put a new diapham in mine and it busted and covered the return hole and would not start.because it had 70lbs fuel pressure.Changed it out and was fine.

 

well mine doensnt really have a screw, the entire top actually turns on the holley's and they come with their own diaphragm and i'm sure that it's perfectly fine in there....... i've had the exact same problem with 3 other FPR's, one being the crane, and the other being the stock one, i've never seen more than 40 on my car since i got it regardless of the FPR.

what other tests can i do to assure that the proper pressure is coming through the lines in the first place before it even gets to the rails? and what pressure should that be with my 255 lph holley pump in there?

 

Do you have a fuel pump issue or a restriction?

Also, I pray to god you checked it out with another fuel pressure guage to verify it?

Fuel pressure guages and compression guages tend to be vary widely in the psi they report, especially when old or been dropped/whacked one too many times.

I find it hard too believe you've never been able to get over 40psi, especially with 3 different setups.

later
Jeremy

 

my fuel pump is definetly fine, i've changed it 2 times since i've had the car, and both with the same fuel pressure

first i had the stock one, (which was an AC delco replacement from the previous owner) and my fuel pressure was dying off quickly right after i turned off the car instead of holding for a while like it should. i changed the pump (venom stock replacement off summit), it did nothing, then i changed the FPR and it fixed it.

second, i had to drop the tank because of a leaking problem, and i changed the pump because my pressure was showing 25-30 psi..... the new pump fixed that problem(holley 255 lph off summit)

i've used different guages, all give me the same readings.

my fuel filter is also definetly fine, i've changed that twice since i've bought the car as well (2nd time i did it because i thought it was the reason behind the 25-30 psi reading i was getting with the venom pump)

i'm also very confused, but since the car runs fine i havent been THAT on top of it........ but i'd just like to investigate a little bit to be safe. i'm beginning to think i have a crimp in one of my fuel lines, or maybe a clog somewhere.... the car DOES have almost 260,000 miles on it.......... anyway, thanks and keep the idea's coming please!

 

Well i was looking at a manual last night it says spec fuel pressure[stock pump] 36-39 lbs presssure is fine.really not sure about the holley pump.

 

The holley web site says supports 650 horse power at 48psi.Does someone know if theres a regulation device in the return line that helps with pressure.The reason i ask is because when my regulator diapham came apart and coverd the return hole i had 70psi of pressure and the car would not run it would turn over but no run.I have a bbk fpr and can adjust it from 43psi to 56 or more i stopped at 56psi.You could try clamping your return line to see if you get more pressure.Just throwing things out there.

 

yeah i guess i'll try something, maybe i'll disconnect the feed line before it gets to the rails and see what kind of pressure i'm getting there, just not sure what it should be. thanks!