fuel pressure drop?

[GreddySpyder]

My car has a problem with stalling if i rev above 4 grand or so and push the clutch in, the rpms just drop to nothing and the car stalls. Sometimes it "catches" itself and retains idle. My B&M fuel pressure gauge took a hit and stopped working, and I just installed a new gauge today and I noticed something.
When the car is running it maintains proper fuel pressure (~42-45psi w/ the regulator line plugged), but after I shut the car off, the fuel pressure drops very slowly. I have extremepsi 680cc injectors, a walbro 255lph pump, and an aeromotive AFPR. I'm not sure if the fuel pressure drop has anything to do with my stalling problem or not, any constructive input would be appreciated.

 

[SnoopySLR]

I had the same problem. It was my Fuel Pressure. I replaced my fuel pressure regulator. It fixed mine, but I'm not turbo. I also don't have near the fuel upgrades you have. Hope you can figure it out, but it was my pressure. Later!

 

[jrou111]

Originally posted by GreddySpyder
after I shut the car off, the fuel pressure drops very slowly...

That's because the pump is no longer pressurizing the system, and it is slowly being returned back into the tank. The vapors are being vented out the gas cap. Also, the AFRP is connected to a vaccuum source, and the car will be at say -15 to -20 inches of vacuum when you shut the car off. this will slowly drop, thus dropping the FP

I'm not sure if the fuel pressure drop has anything to do with my stalling problem or not, any constructive input would be appreciated.

Every car is gonna do this, unless you're getting enough vacuum to drop the pressure to 0. If you're not doing anything this weekend, let's see if we can trouble shoot this problem, because it's seems to be a low throttle problem, and not at WOT, correct me if I'm wrong.



Thanks,