vapor cannister
Team Owner
Joined: Sep 2006
Posts: 31,283
Likes: 4,374
From: Westminster Maryland
Hi O,
The function of the valve is to open when the car is being driven. This pulls air through the charcoal in the the canister which pulls the gasoline vapor stored in the charcoal into the carburetor to be burned. The process is called 'purging'.
When the engine isn't running the valve closes to prevent the escape of any gasoline vapors in the canister which could lead to you smelling gasoline in your garage.
Many people have removed these systems so a used 3 port canister can be found if you so desire.
Regards,
Alan
This canister is from a 71 car.
The function of the valve is to open when the car is being driven. This pulls air through the charcoal in the the canister which pulls the gasoline vapor stored in the charcoal into the carburetor to be burned. The process is called 'purging'.
When the engine isn't running the valve closes to prevent the escape of any gasoline vapors in the canister which could lead to you smelling gasoline in your garage.
Many people have removed these systems so a used 3 port canister can be found if you so desire.
Regards,
Alan
This canister is from a 71 car.
Last edited by Alan 71; Jan 30, 2016 at 08:13 AM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The primary purpose of that valve is to prevent excess air getting into the fuel/air mix at IDLE conditon. The valve is hooked to a "timed" vacuum port on the carb, so that it closes when the throttle plates are closed (but open when the plates open up).
Otherwise, you would get erratic engine idle behavior.
Otherwise, you would get erratic engine idle behavior.
Last edited by 7T1vette; Jan 30, 2016 at 11:02 AM.
Burning Brakes
Joined: Mar 2006
Posts: 829
Likes: 131
From: Spartanburg SC
May I suggest you rebuild your cannnister? Google it. Go to Petsmart, purchase aquarium charcoal and filter material. It's a simple process that totally renews your original cannnister. There are very clear instructions on the net, with pictures.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You could remove it, but a working canister has a useful purpose and no real downside. Be aware that the vapor canister is the "fuel tank vent" for a car so equipped. If you remove it, you need to install a vented gas cap.
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Either your canister is not working properly, or the activated-carbon material in it no longer functions...or someone has wrongly installed a vented cap on your fuel tank. There are some other possibilities that involve the hoses going to the canister and/or the little 'separator' unit at the top of the fuel tank where the vapor hose is connected, also.
Exchanging the carbon material in the vapor canister is not "difficult"...but it does take a bit of work. If the vacuum switch at the top of the canister is defective, the canister likely needs to be replaced. And, if the canister is defective, you could just plug up the line coming from the fuel tank and install a vented fuel cap. The rest of the system will cause no operating problem.
P.S. Fuel fumes can also be caused by pinhole leaks in the fuel tank and/or deteriorating hoses connected to the tank.
Exchanging the carbon material in the vapor canister is not "difficult"...but it does take a bit of work. If the vacuum switch at the top of the canister is defective, the canister likely needs to be replaced. And, if the canister is defective, you could just plug up the line coming from the fuel tank and install a vented fuel cap. The rest of the system will cause no operating problem.
P.S. Fuel fumes can also be caused by pinhole leaks in the fuel tank and/or deteriorating hoses connected to the tank.
Last edited by 7T1vette; Feb 1, 2016 at 05:12 PM.