[ultimateirving]

Originally Posted by roushman90

So, it's been a while and I finally have an update. I ended up taking intake/exhaust manifolds off and redoing everything, replacing all hardware and gaskets. It's all back together finally and I also redid my vacuum lines with new hose and fixed shotty wiring issues all over. Started it today after priming the fuel and oil with fuel fuse pulled. It started up okay and idle but immediately had to shut it off as my fuel pressure was shooting up to 2x what it should be AND leaking fuel from the line directly on the bottom of the fuel filter, AND on return line from the hard line to the soft line! So we, primed the fuel and started it again to check the fuel pressures quickly. It hit about 300kPa at prime before start, then spiked up to above 400kPa right when we started it. I believe stock fuel pressure is around 230 to 240 kPa so I'm obviously way too high!

My Fpr vacuum source is straight to intake manifold but the boost gauge is T'd off of it. So we also tried un "T"ing the boost gauge from the FPR vacuum and it still did the same thing. The only two things I can think of right now is the fpr is fucked or lines incorrect somehow, which is unlikely since I never messed withing anything but the top connections. The FPR adjusting bolt is already backed out as far as possible with the Isis intake manifold.

Any input would be greatly appreciated, also if it makes any difference, I'm running oem hard lines from the back to front, walbro 255, z32 fuel filter, nismo fpr, 370cc stocks, oem fuel rail, isis intake manifold.

So simply asking, what could cause a doubling of my fuel pressure!?

Hooked up the liens backwards on the fuel rail? read through your updates and yes you had a lot of gremlins to fix.
The fuel should go like this Pump>rail>FPR>return to pump