Setting Fuel Pressure

[droppinbottom]

I have been searching and cant seem to find the answer to what I need. I just finished installing my AFPR and I was about to set the fuel pressure and the instructions that came with the kit refer to setting the fuel pressure with the vaccume hose disconnected. Which vaccume hose would it be refering to? I am assuming it is the small hose that was connected to the factory regulator.

Sorry for the Newbie question, but thanks for any help

 

[Quasimondo]

Yes, disconnect the vacum hose that goes into the fuel pressure regulator before making any adjustments.

 

[droppinbottom]

Thanks for confirming that for me. Next question is, I set the pressure to about 38psi with the vaccume hose disconnected and when I hooked the hose up the pressure dropped to about 28psi. Is it supposed to drop that much psi with the hose connected?

 

[Quasimondo]

Yes. The fuel pressure drops in the presence of vacum as well as goes up in the presence of boost.

 

[droppinbottom]

Thanks man. This night just got a whole lot worse.http://www.dsmtuners.com/forums/showthread.php?t=219152

 

[gsxboost20g]

have you looked into the correct routing of that vacuum line? the one to the FPR. I just installed an Aeromotive unit that has a 1:1 boost fuel increase ratio. Are you supposed to retain or remove the stock fuel pressure controll solenoid that is in line of the vacuum line going the the FPR????

 

[steve]

Are you supposed to retain or remove the stock fuel pressure controll solenoid that is in line of the vacuum line going the the FPR?

Your choice but I recommend keeping it. It's there to raise the fuel pressure on hot starts to keep the fuel from vapor locking. What it does is disconnect the manifold from the FPR so that the vacuum doesn't cause the pressure to drop.

On the original subject. If you convert the manifold vacuum to PSI (negative) you'll see that the FPR maintains fuel pressure = base pressure + manifold across the board.

Steve