S14 Slow fuel pressure loss?

[oomgloff2]

I have a fresh well runnin SR swap but when the car sits it has real slow fuel pressure loss and the gauge I put on the line drops to zero overnight. Has a new walbro, swapped with my roomates workin pump and it does the same thing. it has a new filter, put a nismo FPR and a gauge (to eliminate any fpr problem) in the line and the pressure is fine when it runs. only thing I can think of is if there is some sort of valving in the line where the fuel goes into the tank? or an injector, though it runs fine and there is no fuel leaking anywhere... dunno, anyone experience this?

[sx moneypit]

You could have an injector leaking down.The fuel pump has a check valve built in it. If all else fails ,you can buy a check valve that you can install on your fuel line.

[srpowered240sx]

the fuel pressure will not always sit at 40psi all teh time. when the pump is off, the pressure is not being upheld, and it will eventually depressurize.