Thread: Leaking Nismo Fuel pressure regulator

I have heard rumors that the Nismo fuel pressure regulators leak, here or there yet, I see no threads about this problem. I notice my fuel pressure bleeds off over time to 0 when the car is off, so I know there is a problem some where in the system. How would I go about testing to find out where the leak is in my system. They say it should not drop more than 5 p.s.i..

all FPR will leak very slightly at the adjustment screw. if it leaks any where else then you have a problem. your FP should slowly bleed off.

Nismo units don't just leak around the adjustment screw. They also leak around the center coupling where they press the two halves together when building them. You MAY be able to fight off the leaky FPR by using teflon tape on the adjustment screw, then sealing the center section with RTV. That helped mine a tad bit, but the FPR still didn't function properly. I tossed it for my OEM, since I'm running 740's anyway.

What is the stock regulators pressure? I may just go that route.


I wish I knew that before I bought this peice of ..c... I was about to tear down my and replace all of the seals.... Again..... Are there any good quality regulators out there?

dude its suppose to go back down the zero over time. the rail does not stay pressurise. if that was the case then the pump would never have to prime the system to start the car.

Right but I also heard that the system should not lose more than 15 p.s.i after shut down. Unless I was being fed the wrong info. Correct me if I am wrong though.

Either stock, or switch to an Aeromotive unit. Those are built like rocks.

Stock pressure with vacuum line disconnected and capped is 44psi. Around 36~38psi with vacuum connected, depending on how much vacuum you have.



Jen, my setup with the stock FPR held fuel pressure overnight. I would walk out and check it in the morning, and I'd still have around 30psi of fuel pressure.

Aeromotive even says in its manual that it will leak air around the screw. the nismo unit works great for me and a lot of other people. there is no need to go out and spend alot more money to get a Aeromotive unit especialy if your using the stock rail.

Maybe some units are faulty some are not. I mean it's Nismo it's not like it's a poor quality product.

Well, apparently from what I've read here and other places, their FPRs aren't worth it.