Evaporative Emissions System: Description

Evaporation Control System (ECS) is designed to minimize the escape of fuel vapors to the atmosphere. Included in the system are a special fuel tank and filler cap, liquid-vapor separator, carbon canister, canister purge hoses, and carburetor modifications. Fuel vapors which would otherwise escape to the atmosphere are directed into the carbon canister. The carbon adsorb the vapors and stores them. The vapor is removed from the canister during periods of engine operation as manifold vacuum draws the vapors into the engine and burns them. This system was first released in 1970 for vehicles originally sold in California. In 1971, the Federal Government required that all trucks with a gross weight of less than 6, 000 lbs., were to be equipped with such a system.