Evaporative Emissions System: Description and Operation

Evaporative Emissions Control (EVAP) System Schematic:

Charcoal Canister:

Fuel Pressure Control Valve:

PURPOSE
To prevent the discharge of fuel vapors into the atmosphere under all operating conditions.

OPERATION
The Evaporative Emission Control System (EECS) uses a activated carbon storage canister. Gasoline vapors from the fuel tank flow into the tube labeled "TANK." Any liquid fuel goes into a reservoir at the bottom of the canister to protect the carbon bed above. The vapors are absorbed into the carbon. When the engine is running above idle speed and commanded by the ECM, the canister is purged by intake air flow and consumed in the normal combustion process. When the engine is stopped, the canister purge solenoid is closed and fuel vapor is retained within the system.