confusion

[herminator]

I have read about the charcoal canister associated with the fuel tank on my '73 but didn't know anything about it. When I traced the line from the rollover valve, it appears to go to the vacume tank in the left front fender?! Are they one in the same?

 

[Vettehead Mikey]

The black plastic coffee can sized thing in the left fender is the charcoal canister. The vacuum tank for the headlights is a horizontal tube between the radiator and front bumper. Nothing to do with each other.

 

[herminator]

Mikey thanks, but whay are there vacume tubes going in and out of the charcoal canister?

 

[6880 Mike]

Mikey thanks, but whay are there vacume tubes going in and out of the charcoal canister?

Fuel evaporation emissions controls. Your owner's manual probably has a blurb about it. Gasoline vapors were routed through the charcoal canister and eventually back to the fuel tank.

 

[Vettehead Mikey]

Fuel evaporation emissions controls. Your owner's manual probably has a blurb about it. Gasoline vapors were routed through the charcoal canister and eventually back to the fuel tank.

Yup, and it's also the routing for air to enter the tank as the gas level decreases without letting nasty vapours back out to stink up our garages.

 

[JohnZ]

Mikey thanks, but whay are there vacume tubes going in and out of the charcoal canister?

The activated charcoal in the canister adsorbs fuel vapors until the purge valve on top opens and the vapors are pulled (by manifold vacuum) into the intake manifold and burned with the incoming charge. The purge valve is controlled by one of the vacuum relays; the Shop Manual explains it.

 

[herminator]

OK, the situation was simplified by accidently breaking the hose nipple off of the vapor seperator while reinstalling the tank the night before I was to fire the new motor. Since I couldn't get a new seperator in time, I sealed the broken nipple and left the gas cap off for venting. Have started the car and run it for an hour over 2 days with no gas smell in the garage. next, I will drill 2 1/16" holes in the cap for venting, run it like that and watch/smell for problems. i really don't want to spend $60 for a new VS and R&R the tank since if I don't have to.