sai injects air during start-up to improve emissions. the sai system consists of an air pump connected to an electrically-actuated pneumatic valve mounted on one head with a connector pipe to the other head.
there is also a charcoal canister located in the front right wheel well where evaporated fuel (evap) accumulates when the car sits. on start up this canister is purged to the intake via two valves - an electric valve located by the intake (the evap canister purge valve) and a second electric valve located on the charcoal canister. (the operating purge valve).
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