Fuel Pressure Drops FAST

[eclpsegsx12]

Read my mod list to see what i have dont fully, but for my fuel system i run 780's, walbro 255 pump, Buschur AFPR, stock rail....

I was at the dyno and whenever i would shut my car down my fuel pressure dropped to 0 in 10 seconds or less. I know that i should be able to hold my pressure and it will slowly go down in about 30 minutes or so but this shouldnt be happening. What are your suggestions and best way to go about checking for the problem.

My thoughts could be the check thing in the fuel pump? Im not too familiar with it. I think he said check valve that could be bad. Another idea could be the AFPR loosing pressure too fast and finally an injector being stuck open . What can i do to check where im losing pressure and whats my best bet on where the problem is? I need to get this fixed so i can get back on the dyno and tune my beast! Thanks tuners

 

[steve]

I'd be willing to bet that if you could put your stock FPR back on you would see what's considered to be the normal pressure decay time. People have been reporting for awhile that the aftermarket universal AFPRs tend to drop pressure quickly after the pump is shut off. I know with my spoolinup on my 1G my pressure drops in 5 to 10 mins but I have no problem regulating and maintaining pressure when the pump is on. I verified that it was the AFPR and not something else in my fuel system by putting the stock FPR on.

Steve

 

[eclpsegsx12]

Cool, finally someone with some input...I appreciate it. Ill see what happens when i swap regulators. Why would the pressure drop fast with an AFPR as opposed to a stock FPR?

 

[steve]

Why would the pressure drop fast with an AFPR as opposed to a stock FPR?

I can only speculate at the cause since I haven't taken mine apart but I suspect the larger return ports don't quite seal as tightly as the small on in the stock FRP does.

Steve

 

[Defiant]

I was at the dyno and whenever i would shut my car down my fuel pressure dropped to 0 in 10 seconds or less. I know that i should be able to hold my pressure and it will slowly go down in about 30 minutes or so

According to whom? If you're not having issues while it's running, you don't have a problem.