DESCRIPTION
The purpose of the Evaporation Control System is to prevent gasoline vapors (hydrocarbons), from the fuel tank and carburetor, from entering the atmosphere.
When fuel evaporates in the fuel tank or in the carburetor float chamber, the vapors pass through vent hoses to a charcoal canister.
The vapors are stored in the canister until they are drawn into the intake manifold after the engine begins to run. (Scheme 35)and (Scheme 36).
CARBURETOR FUEL BOWL
The fuel bowls on all carburetors are vented internally. Because of internal venting of the fuel bowl, some models do not require venting to the canister. In this case, the bowl vent port on the canister will be capped. Most carburetors are also externally vented to the charcoal canister.
CHARCOAL CANISTER
An open canister is used on all models except 3.7L and 5.2L engines which use a sealed canister. Fuel vapors from the fuel tank are stored in activated charcoal while the engine is not operating.
When the engine is operating, vapor is purged from the charcoal canister into the engine where it is burned with the air/fuel mixture.
FUEL TANK FILLER CAP
Relief valves in the fuel tank filler cap operate to prevent excessive pressure or vacuum in the fuel tank. The proper replacement cap must be used if the original cap is lost or damaged.
| CAUTION | Remove the fuel tank filler cap prior to removing or repairing fuel lines. |
ROLLOVER/VAPOR SEPARATOR
All models are equipped with a rollover/vapor separator valve to prevent fuel leakage if the vehicle is accidentally rolled over. This valve is located on top of the fuel tank.
TESTING
Note. Testing information not available.
MAINTENANCE
The only service that is required is to check the filter located on the bottom of the charcoal canister every 30,000 miles.
Replacement is only required if the vehicle is frequently driven in dusty areas or the filter is dirty or clogged. All hoses should be inspected periodically and replaced if cracked or leaking.
