I believe that my 1995 Camaro Z28 has dual cats...one located underneath the passenger seat area and the other that looks like a canister shaped object near the engine compartment.

What is that canister-looking catalytic converter called? Does anyone know the part name or part number for that?

Also, what is a canister purge valve and what role does that play in helping me pass smog? Does something like that need replacement every so often?

 

Since your 95 is a "CA" car, and an A4, it will have a dual-cat exhaust. There is one catalytic convertor in each branch of the Y-pipe coming from the exhaust manifolds. On the drivers side, the round "canister" shaped catalytic convertor is right up agaionst the outlet of the exhaust manifold. On the passenger side, it is the big flat catalytic convertor under the passengers feet. They are both the same devices... catalytic convertors... they just happen to be different shapes. If you need a replacement, you just have to ask for "a catalytic convertor for the drivers side."

The fuel tank system is "sealed". The fill cap is unvented and has a seal on it to prevent hydrocarbon (gasoline) vapors from coming out of the tank and polluting the atmosphere. In order to relieve pressure buildup in the tank, and to allow the tank to "breath" as fuel is pumped out of it, there is a vent line that goes to a charcoal filled canister. The canister is located in the drivers rear fender, behind the fill pipe. When vapors vent out of the fuel tank, the charcoal absorbs the hydrocarbons.

Then when the engine is running, the EEC purge solenoid on a bracket on the passenger side of the intake manifold will open, and pull air through the canister to pick up the hydrocarbon vapors, pull them through the plastic line that runs along with the fuel supply and return lines, through the purge solenoid, and into a port on the side of the throttle body. That way, the air and hydrocarbon purge gets burned in the combustion process.

The charcoal canister can get saturated with liquid fuel, or the charcoal can "wear out". But it isn't likely that this would show up on a smog test. They don't test the air that vents out of the EEC canister.

The catalytic convertors and EEC canister have nothing to do with each other.

 

Thanks for the detailed info!