my stock fuel pressure with the stock regulator was always around 40psi...... i just installed the holley adjustable regulator, and if i tighten the screw on it all the way down, my pressure goes up to 40 psi.... if i loosen it, my pressure lowers.

very simple question, that probably has a complicated answer, WHY won't my pressure go past 40psi?!?!!?

things it simply can NOT be:
1)fuel pump has been changed numerous times, pressure has never been more than 40 psi, my pump is fine.
2)fuel filter has been changed twice since i've had the car, i've never seen the pressure past 40 psi, my filter is fine.

 

Under what conditions are you measuring? Engine running? Vaccum line off?

 

engine running, off and vaccum line off the pressure pretty much stays the same......... when i take off the vaccum line the pressure goes up maybe 3-5 psi

 

IS IT A STOCK PUMP.......I JUST INSTALLED A WALBRO AND IT WORKED FINE WITH MY HOME-MADE AFPR.47 PSI

 

my fuel pump is a holley 255 lph pump that i bought from summit

 

Perhaps your AFPR is bad

 

i dont think it is because before i installed this one, i installed crane's and i had the same issue.... i ended up breaking the adjustment screw on it because i didnt think it was completely tightened lol.... thats why i got the holley one

 

the first one I bought from summit I noticed a small tear in the diaphram

I sent it back before putting it on my car, the box was all battered and beat up

I hope they did not send you that one.

 

thats weird....I cant get my holley past 40 psi either on a stock pump. I had it dialed to 48 psi brand new, then I went to turn it down and it jumped down very quickly to 30 psi....It was so hard to get it to clockwise and I could not get past 40. When i close off the fuel return line the car dies. I thought this was a sign of a bad fpr


Now my car isnt starting. Not sure if its the pump or fpr or relay

 

Is the pressure guage ok?

 

yeah i'm pretty sure the guage is perfectly fine, i put another guage on their when i had the crane on it just to make sure it wasn't messed up..... i'm beginning to think i have like a crink in my lines somewhere :-/