Hi, Perry....One question....Does your unburned fuel (from the fuel rail) go back into your sump tank also?   Or do you return the unused fuel to one of your fuel tanks?  If I were returning fuel to one of the main tanks, I would think that venting the sump would be appropriate, but since I am sending fuel undere pressure back into the sump tank, I am concerned that once the sump tank is full, the additional fuel pumped back into the sump tank would take the path of least resistance....out the vent instead of back up the fuel line into the tank?   Thanks for your input.  Paul Conner

One other comment Paul: the fuel return from the fuel rail is not pressurized. The pressure regulator maintains HP on the fuel rail side, but the fuel return output back to the sump is not under high pressure.