Pullngz

Just looking for info really, I have my pump out right now. 94 Trans Am by the way. I have 4 hard lines that come off the top of the pump. Starting on the drivers side of the pump, I have the return line,vacuum line from intake, main line, and the canister line. The vac line just goes in the top of the tank and is open(no hoses connected to it) is that just for vapor evacuation in the tank? The one that goes to the charcoal canister does basically the same thing only it has some sort of valve or something attached to the top, just inside the tank.

Thanks for the info guys
Pull.