Fuel Pressure changes at each start up

[articzap]

I posted this in the CA section but I think help from a broader audience would better help me discuss ideas.

Some details you may wish to know.

-Walbro 255 lph-Synapse FPR-Open vented gas tank-New fuel filter

Every time I start the car I'll get a different fuel pressure then the previous time. It can range from only a couple PSI to almost 10 PSI at times. Once the car is started and running, it will hold that fuel pressure fine until the car is shut off. If I restart it right away, it will be where it previously was. If I give it a little while before I restart it, it will have decided to change its mind again.

If I fill up the fuel tank, it seems to want to read higher but doesn't necessary have higher fuel pressure with fuller tank. It will always vary.

After talking to Synapse they suggested that I didn't have enough preload on the adjustment spring. I've tried many combos of bypass fitting sizes and different preloads with no avail.

I'm at the point that I think its the FPR failing, a nick in the rubber line between the pump and the top of tank.

Any ideas or comments I'd appreciate. I can't get my car tuned until I fix this fueling issue.

[articzap]

Help me out!

[r3v_v3ng3]

Some details you may wish to know.

-Walbro 255 lph-Synapse FPR-Open vented gas tank-New fuel filter

whats open vented gas tank? does it mean no gas cap? shouldn't it be closed to hold the pressure?