Cant lower fuel pressure

[joyfil2001]

I can not lower my base fuel pressure below 48psi. Vacuum does not affect it either. I searched and found this thread:
http://www.dsmtuners.com/forums/pro...cant-lower-my-fuel-pressur-below-46-psig.html
which is exactly the same situation I am in. I'm going to try and run the return to a bucket and see if the pressure changes but I really hope this isn't the problem. Has anyone else run into this situation? Is it possible that an old fuel filter can cause this? I dont think its ever been changed and I am planning on doing it soon. Any feedback is appreciated. Thanks.

 

[NOSLO2PT0]

Try turning the adjusting bolt on the AFPR a few turns counter-clockwise? That should drop the pressure. If not, I would pull the AFPR apart and see if there is any debris blocking the flow out of the return outlet.

 

[joyfil2001]

I guess I should have added more details. I have had three FPR's on the car and two different fuel pressure gauges. So I know its not the FPR and its not the gauge. I can back the screw all the way out but 48 is as low as it goes.

 

[NOSLO2PT0]

You check your voltage at the pump? Could be possible you got some crazy voltage back there that's increasing your volume.

 

[joyfil2001]

Thats a good point, I never thought of that. It is currently wired direct to the battery so I dont know how the voltage would be more than 12v. But I will check.

 

[turboglenn]

There's a siphon in the tank that's part of the return line, the hole in it is too small from the factory to allow larger pumps to bypass enough fuel to get the pressure below 40psi usually. There's threads on here about this and plenty of them have what size drill bit you need to use to correct this... you don't just wantt o go "big" on the hole as going too large is said to cause problems as well.

 

[joyfil2001]

I read about the "siphon" problem too. However I dont want to go drilling if I dont know for sure thats the problem. But please keep the comments coming. I want to go throught the "checklist" and find the damn problem.

 

[turboglenn]

Besides the first suspect of a regulator that's either too small or has too small of a return line on it, the siphon is the only thing left.

 

[trunks]

Any updates on this? I'm in the same situation.