Air Injection: Description and Operation

Fig. 84 Air injection system.:

Fig. 85 Air injection system.:

The air injection system, Figs. 84 and 85, provides fresh air to the exhaust manifold to continue the combustion process and promote oxidization of hydrocarbons. Vacuum created by exhaust pulses is used to draw air from the air cleaner into the manifold. Air flow is controlled by a vacuum operated air suction valve. Vacuum signals to the air suction valve are controlled by an air suction control solenoid valve and the solenoid is operated by the emission system electronic control unit.
When the air suction control solenoid valve is energized, vacuum signals are applied to the air suction valve diaphragm. When vacuum is applied to the air suction valve diaphragm, the diaphragm opens the secondary air passage and air flows into the exhaust manifold through reed valves. The reed valves prevent exhaust from traveling back through the system into the air cleaner.