Pulse Air Injection System

Fig. 33 Pulse air system. 1983---88 6-258:

The system which is used on 6-258 engines, uses the alternating exhaust pressure pulsations instead of an air pump to inject air into the exhaust system, Fig. 33. Air is routed from the air cleaner through a hose to the air control valve which is controlled by an air switch solenoid. The air switch solenoid is in turn controlled by the CEC system Micro Computer Unit (MCU). At the appropriate signal from the CEC system the air control valve is opened and air is allowed to flow through the air injection check valve. From there the air enters the exhaust stream either at the front exhaust pipe (upstream) or at the catalytic converter (downstream) depending on which of the air injection circuits has been opened.