Is anyone retaining the purge, pressure control, drain solenoids and the fuel tank pressure sensor. I was contemplating keeping them so the emissions self test would work. After looking at the original system on the Subaru it utilized multiple vents, in particular the main vent which is held closed by a float when the tank is half full or more. It looks to me that the system would draw a vacuum on the tank when the tank was half full by closing the drain valve and pressure control valve. The vacuum would be detected by the sensor and indicate a sealed system. The problem I see is that the FFR supplied fuel filler cap is not setup with a vacuum relief diaphragm like the stock Subaru one is. If there was ever a failure somewhere in the system it could possibly damage the tank(implode). What I am considering now is just using the purge solenoid I'm just unsure if it will work with out the rest of the components, in particular the pressure sensor. I think a vapor canister will eventually get saturated without a purge cycle every so often. My other thought is installing a vacuum relief valve right after the vent I just don't know what pressure it should be set for.