GASOLINE MODELS
System is designed to route fuel vapor from fuel tank and carburetor into carbon canister where they are stored until intake vacuum draws vapor into combustion chambers for burning.
Components include a sealed filler cap, vapor separator tank, charcoal canister and purge control valve, solenoid operated vent switching valve (carbureted engines), 2-way valve, evaporator valve, and connecting lines and hoses.
OPERATION
When engine is not running, fuel vapor from tank vents through evaporator valve, or depending on model, into charcoal canister. On carbureted models, the vent switching valve opens to allow carburetor vapor to vent to charcoal canister. Purge control valve is closed when engine is not running.
When engine is running, vent switching valve closes by solenoid action (if equipped). Purge control valve opens on vacuum signal from distributor advance mechanism and allows canister vapor to be drawn into intake manifold.
Purge control valve opens when vacuum acting on purge control valve is 7.1-8.7 in. Hg on 1.9L engine, or 2.8-4.4 in. Hg on 2.0L turbo engine. When valve is opened, vapor is drawn into intake manifold.
MAINTENANCE
The system and all components should be inspected for condition and function every 15,000 miles. Check all hoses and lines for deterioration, damage, and obstructions.
VAPOR SEPARATOR TANK
Remove hoses from tank and test for leaks by blowing into any outlet while sealing other 2 outlets.
EVAPORATOR VALVE
Remove hoses from valve and remove valve from vehicle. Blow into valve and ensure air flows through valve in both directions. Block one port and ensure air does not leak from valve.
SYSTEM TESTING
- With ignition in "OFF" position, remove evaporation hose at common chamber and blow into hose. (Scheme 4) Hose must be free of obstructions and air must flow into canister. Reconnect hose to common chamber.
- With engine running at idle, remove vapor hose to fuel tank at canister. Vacuum must not be present at canister's purge air port and port to fuel tank. Replace valve if it does not operate as outlined.
