Ok, on 1st gen 1985 Fuel Injected Rx7's gas tank, there are three lines. I think the big one is fuel pickup (correct me if I'm wrong), the smaller one is fuel return, what is this third line for? Any help appericated!

 

I am completely guessing since I am at work, but I think it's an emissions line to collect gas vapors from the tank to be sucked into the engine on start-up. Probably runs to a charcoal canister somewhere under the hood. The Cannucks like it when I guess at stuff...

 

mar3 is correct it is a vent line that goes to the charcol canister

peace