I just installed a afpr and now when i shut my car off the fuel pressure will slowly rise from 50 psi untill it pegs my accel gauge. Any one have any ideas of what this could be. Also the neddle on my gauge jumps around +/- 4-5 psi when runing and it was pretty steady before i put the new afpr on. Thanks for any help. James

... That's crazy.. The only thing I could imagine that being would be your fuel pump isn't shutting off.. or possibly something like, the fuel can't get back into the fuel tank, and maybe the heat is causing the fuel to expand?

pull the fuel pump fuse and see if it stops rising, maybe? is there any abnormal current draw while the car is off?

I belive its normal. I know with my stock regulator it does the same thing, but it dosent go as high as yours. How high does yours exactly go?

why would the pressure rise after the car is off, though..

on new cars, my GUESS would be that the ECM closes off the gas tank vent in a effort to reduce emissions. the closed system is being heated by the warm motor, and that causes the fuel to turn to vapor and create pressure..


but thats assuming that you have a tank vent controlled by the ECM.

The gauge i have goes up to 65 psi and has a little pin to stop it from moving any more. The fuel pump shuts off. I ran the car with the stock apr and checked the stock psi then i put on the afpr put it all back together and this is happening. My fuel pressure gauge jumps around now when the cars runing +/- 5 psi. It didnt do this when i checked the stock one an hour earlyer.