Evaporative Emissions System: Description and Operation

Evaporative Emission Controls:

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The system consists of the following components:

CHARCOAL CANISTER:
A canister for the temporary storage of fuel vapor until it can be cycled through the engine and burned. Located passenger side of engine compartment, below the fuel filter.

VAPOR PURGE CONTROL SYSTEM:
Canister purging is accomplished by drawing fresh air through the canister and into a port on the throttle body. The ported vacuum is controlled by the purge control solenoid valve, located drivers side of engine compartment, bolted to the firewall next to the brake master cylinder and the purge control diaphragm valve, located on top of the charcoal canister. The purge control solenoid turns off after the engine is started, if the coolant temperature is above 167°F (75°C) on 16 VALVE VTEC (D15Z1): engine, or 158°F (70°C) for all other engines.


FUEL TANK VAPOR CONTROL SYSTEM:
The Fuel Cut-Off Valve and Liquid Vapor Separator prohibit liquid fuel from entering the two-way valve. When fuel vapor pressure in the fuel tank is higher than the set value of the two-way valve, which is bolted to the left front corner of the fuel tank, the valve opens and regulates the flow of fuel vapor to the canister. If the two-way valve should fail, the pressure (or vacuum) in the tank is vented through the filler cap.