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Subject Fuel leaking out top of fuel tank bulkhead - deleted CC and
     
Posted by Haasz32 on March 16, 2018 at 7:42 PM
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Message new Tomei adjustable FPR. I just installed Ash Massive I/Cs so I had to delete the carbon canister. I did not cap off the fuel vent line (it's connected to the hardline that disappears into the frame rail), so I think the tank is vented like it should be.

I have had a Walbro 485 pump for a few years now, but I decided to remove the FPCU to prevent any burn-up issues with that board. I wired up the fuel pump using the nice Radium Engineering wiring system that allows the wiring to pass through the bulkhead and utilizes large wires. I tied the other end of this wire to ground and the stock power wire that heads to the fuel pump relay so the pump gets power like stock but ground is always connected so the fuel pump will run at 12V all the time when it should be running. Because of this, I installed a Tomei adjustable FPR and hooked up a temporary fuel pressure gauge to set the pressure level. I retained the stock damper.

I got the car started and I was trying to set the pressure. It's reading 30 psi with the vacuum hose disconnected, which I know is too low (needs to be 43.5 psi at atmospheric pressure). I was turning the adjustment screw and I wasn't able to raise the fuel pressure. I could lower it a few PSI but I couldn't really raise it. Around the same time I started smelling fuel so I shut off the car. I had fuel leaking out of my fuel tank bulkhead. It wasn't leaking from the rubber fuel lines. I was leaking out around the bulkhead plate.

It's highly possible the 0-ring didn't seal well, allowing high positive tank pressure to force fuel out of the bulkhead. I'm sure that needs to get addressed. However, it seems like I have way too much pressure in the fuel tank. The obvious thing would be for the fuel vent line to be capped or restricted in some way, not allowing any pressure release. However, that line is open, as the CC is no longer on the car.

Does anyone know what could be causing the tank pressure, or if I may have normal tank pressure but just a bad seal on the lid? And if there is a venting problem causing too much pressure, does it make sense that it is affecting the fuel line pressure in the engine bay such that I can't increase fuel pressure above about 32 psi? Or are the 2 things separate problems?

     
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