Vapor/Charcoal Canisters

[BlueBaron762x39]

My charcoal canister appears to be the source of the fuel tank pressurizing in my 1979 Olds 403 Trans Am.  If I disconnect the vent line from the fuel tank to canister (disconnected right at where it connects to the canister) my fuel tank does not pressurize.  This charcoal canister is completely empty of foam and charcoal.  Is the connection point for the fuel tank to the canister normally free flowing or is there an internal valve of some kind at that connection point?  If I can't find a way to fix this canister or find a decent original replacement are there any canisters available for newer cars that have enough connection ports (4) that I could use in it's place?

[Warren Seale]

I'd check to see if the cansister port that goes to the tank is clear by blowing through it.  If it is indeed stopped up see if you can simply push a wire throught the pipe.  You might luck out and find that the problem in in the pipe.

[BlueBaron762x39]

I'd check to see if the cansister port that goes to the tank is clear by blowing through it.  If it is indeed stopped up see if you can simply push a wire throught the pipe.  You might luck out and find that the problem in in the pipe.

This was indeed the problem after all.  Rather then trying to clear the obstructed canister port I replaced it with another used one that was not obstructed.  Now the fuel tank vents properly.