Description And Operation: Notes

To reduce the emission of fuel vapor, the fuel tank is vented to atmosphere through activated evaporative emission canisters which collect the fuel vapor. The evaporative emission canister is periodically purged of fuel vapor when the evaporative emission canister purge valve opens the vapor line between the evaporative emission canister and the air intake induction elbow. This action allows manifold depression to draw air through the evaporative emission canister atmospheric vent, taking up the deposited fuel vapor from the charcoal adsorber inside the evaporative emission canister and burning the resulting fuel vapor in the engine.

There are two variants of the evaporative emissions system. All systems use the charcoal adsorber storage evaporative emission canisters and purge valve and operate as described above. The specific features of each system are described below. The evaporative systems are designated as:

• Vehicles with on-board refueling vapor recovery
• Vehicles without on-board refueling vapor recovery