Electric Air Control (EAC) Valves With Relief Tube

When engine is cold or at wide open throttle, control module energizes solenoid on valve, and air is directed to exhaust manifold ports. When coolant temperature increases, solenoid is de-energized and air goes into air cleaner.

At higher engine speeds, air is directed to air cleaner through pressure relief valve (if equipped), even though solenoid may be energized. Air should not be entering exhaust manifold during closed loop mode.

During deceleration, the increased manifold vacuum signal directs air to air cleaner. Check valve on air injection pipe prevents exhaust gases from entering air pump. Solenoid is de-energized under rich mixture condition or if SERVICE ENGINE SOON light is on.