Evaporative Emission Control Canister: Description and Operation

Canister and Purge Valve:

PURPOSE
Storage container for fuel vapor.

LOCATION
On R.H. side of firewall.

OPERATION
The purge valve is an integral part of the canister. When the engine is running, vacuum (control vacuum signal) is supplied to the top of the purge valve to lift the valve diaphragm and open the valve. The lower tube on the purge valve is connected to manifold vacuum on the throttle body.
The control valve only opens when sufficient vacuum is applied, thus preventing purge under conditions of low ported vacuum.


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