DESCRIPTION
Fuel evaporation system prevents the escape of fuel vapor into the atmosphere. System consists of a special fuel tank with integral expansion tank (if used), vapor separator tank (if equipped), vacuum relief filler cap, overfill limiter (2-way valve), fuel check valve, thermo valve (if used), charcoal canister, air cleaner carbon element (Ram-50), purge control valve, bowl vent valve (carbureted models only), and connecting lines and hoses.
Scheme 1
Scheme 2
OPERATION
When ignition switch is in "OFF" position, fuel tank and carburetor float bowl vapors are vented into charcoal canister. When engine is running above idle and warmed to normal operating temperature, thermo valve will open and allow vacuum to open purge control valve.
Canister vapors are then drawn into intake manifold through purge control valve for burning. Purge control valve is kept closed during idle and engine warm-up to reduce HC and CO emissions. On Colt Turbo purge control valve opens when the pressure difference between the turbocharged and throttle-port pressures exceeds a preset value.
Carbureted
- With engine warmed to normal operating temperature and ignition switch in the "OFF" position, remove purge hose from air cleaner and blow air into it. Air should not flow through purge control valve.
- Start engine and run at 1500-2000 RPM. Blow into hose and check that air flows through purge control valve. If valve does not operate as outlined, check thermo valve operation and connecting vacuum lines and hoses for breaks and obstructions.
Scheme 3
Fuel Injected
Disconnect hoses from purge control valve and remove valve. On all except Colt Vista models, apply 7.8 in. Hg to top vertical nipple of purge control valve. On Colt Vista, models, apply 7.8 in. Hg to bottom nipple of purge control valve. (Scheme 3) Blow into purge control valve's port to canister and check that air flows through valve. Replace valve if it does not operate as outlined.
Scheme 4
Scheme 5
OVERFILL LIMITER (2-WAY VALVE)
Remove valve and blow lightly through both inlet and outlet. If air passes with light resistance in both directions, valve is good.
Scheme 6
MAINTENANCE
Every 5 years or 50,000 miles, check fuel evaporation system for leaks and obstructions. Disconnect both ends of fuel vapor vent line and blow line clean with compressed air. Check operation of overfill limiter and replace all vapor/vacuum hoses and charcoal canister. Check filler cap packing for deterioration and filler tube sealing surface.
