Fuel Tank Vent questiion

[Beef6]

I installed an IPS fuel hat yesterday and was having issues with a leak, turns out it was caused by excess fuel tank pressure due to a vac reduction and the vent line being capped. The fuel was bubbling out around the studs that pass through the fuel had for the electrical connections.

I added 2ft of vacuum line straight onto the line coming from the tank, my question is do I need the blue check valve? It seems to stick a bit and was still building pressure even with the line not capped in the engine bay.

Its almost completely stopped leaking now, Im going to use some Permatex fuel resistant sealant to completely seal the holes where the studs go through just to make sure.


-Josh