CALIFORNIA Models
Secondary (fresh) air is supplied to the exhaust port on the No. 2 and No. 4 cylinder side by the air suction valve (ASV-I) with cut-off valve. The air injection system is controlled by both coolant temperature sensed by the thermosensor and time governed by the ECM.
When coolant temperature is less than 95°F (35°C), the electronic control module signals the solenoid valve to allow manifold vacuum to open the cut-off valve. This enables the suction valve to operate. The solenoid valve remains open for a period of 123 seconds.
During this time, if a low vacuum condition (such as wide open throttle) should exist, a check valve is used to maintain vacuum at the solenoid and cut-off valve.
At the end of the 123 second period, the control module turns off the solenoid valve signal. Vacuum is no longer supplied to the cut-off valve and air injection is terminated. See Fig 1 .