L-Series Wagon 2WD F4-1781cc 1.8L SOHC (Carb) (1986)
Pulsed Secondary Air Injection: Description and Operation
Air Injection System - California
Fig. 25 Air injection system.
This system, Fig. 25 promotes oxidation of hydrocarbons and carbon monoxide under cold operating conditions. It consists of an air suction valve, cutoff
valve, air suction pipe, air introduction hose, air filter, thermosensor, solenoid valve, check valve, and electronic control module.
Exhaust gas pulses are transmitted to air suction valve through air suction pipe. When a negative pressure is present, ambient air flows from air cleaner to
exhaust passage. When positive pressure is present, air switching valve is inoperative.
the system incorporates thermosensor and an ECM timer to govern air injection operation. When coolant temperature is below a specific value, ECM
opens intake manifold vacuum passage of solenoid valve for 123 seconds, which causes diaphragm vacuum actuator to open cutoff valve and operate air
switching valve. After 123 seconds, the ECM closes vacuum passage of solenoid valve and opens atmospheric pressure passage. The vacuum in vacuum
chamber of cutoff valve then flows out through solenoid valve, which closes cut-off valve and deactivates air switching valve.