Evaporative Emissions System: Testing and Inspection

Fig. 3 EEC system:

The evaporative emission control system, Fig. 3, draws fuel vapor, emitted from the fuel tank and carburetor when the engine is not operating, into a charcoal canister. The system comprises a tank pressure control valve, a charcoal canister, a venting switching valve, a thermal vacuum valve and connecting lines. When the engine is not operating, fuel vapor is stored in the charcoal canister. When the engine is started, the stored vapor is mixed with ambient air and fed directly to the intake manifold for combustion.