Im having a bitch of a time trying to tune my car because i cant seem to get over about 38 psi on my HSR at idle, even at full turn it only makes between 38-35. I have a new 255lph fuel pump and an inline pump for the Supercharger and im still only making 38, in fact it drops when i give it throttle, do you think my AFPR is bad, what else could it be ? I have a pressure guage mounted directly on the back of the holley rail and it's brand new, what else might be suspect ?

 

first thing id check would be the fuel filter.

after that, i would suspect the pumps...

 

I checked and double checked my routings on the fmu, inline pump, feed line, return line ect and still i cant make above 38 psi at idle, the fuel filter is only about a year old, and i havent drivin the car in that long really so it should be fine. I cant seem to figure out what the hell is going on here, any other ideas guys ? Even if the inline were bad, the 255Lph should be able to push me into stock pressure......

 

Dumb question....


Are you pulling the vaccum line from the regulator? The way I understood was your fuel pressure will always be around that no matter what with the vaccum line connected. Pulling it off shows you what your fp is at WOT.


With mine I have a constant 36 psi at idle. When I pull the vaccum line, I get 44 Psi.

 

Yea, even with the vac line off and it plugged i cant make over 40 turned all the way up, any other sugesstions ?

 

what size lines are you using, just curious.

 

Try crimping the return fuel line momentarily with a pair of pliers. Fuel pressure should go to the maximum for your pump. If pressure goes high, the diaphram in the FPR is probably shot. If no increase, get a new pump.

 

I would suspect a bad regulator. Unfortunately, the regulators used on these intakes are notorious for crapping out. Good luck!