flippincamaro

iTrader: (23)

Alright guys, My 00 z28 has a few lil mods, Ls6 cam, intake, mild head work, an a 255lph fuel pump. Well I got the car dyno tuned an the mechanical an electric fuel pressure gauges were right between 58-60psi now over the last couple of weeks my pressure has been rising, I thought my electric gauge was going bad so checked it with the mechanical gauge an they read the same, Now my fuel pressure is reading 75psi here is a pic i took of the electric gauge tonight while i was driving down the highway cruising, I know glowshift isnt a popular gauge or anything but i have tried 3 mechanical gauges an they read the same, One is my mechanical gauge that is always under my hood an its a jegs gauge, Other than the pump my fuel system is stock. What you guys think it might be? I was thinking maybe the returnless 3 way valve like thing under the car near the tank which kinda acts as a return may be stopping up? Not sure but any help would be great thanks guys

Old Geezer

iTrader: (3)

Your idea on the return is where I'd start...

Lonnies Performance

iTrader: (16)

First I commend you on double checking the fuel pressure with 2 gauges.

The t-fitting under the car is just a fitting, there are no functional parts there. Unless a line is pinched under the car, there is little else to blame than the regulator. Verify nothing is damaged from the previous pump install.

The regulator is in the fuel tank & can be easily swapped. The trouble is removing the sender from the tank to get to it.

I have new factory regulators in stock if interested.

flippincamaro

iTrader: (23)

Thanks Lonnie, I didnt even think about that, How much for the reg?

Lonnies Performance

iTrader: (16)

Give me call at your convenience, maybe we can also diagnose things further

O2Form

The return is blocked someplace, might even be at the regulator itself. That 75 psi you see is the test head pressure you see if you block off the return to test the pump.

Lonnies Performance

iTrader: (16)

Mayber on a stock pump.... I have seen many 255's approach 90 psi if deadheaded.