Air Injection: Description and Operation

AIR INJECTION SYSTEM

Air Injection System Components - Typical:

The air injection system is used on 5.9L V-8 and 8.0L V-10 heavy duty cycle (HDC) gas powered engines only. The air injection system consists of:
- A belt-driven air injection (AIR) pump
- Two air pressure relief valves
- Rubber connecting air injection hoses with clamps metal connecting air tubes
- Two one-way check valves

The air injection system adds a controlled amount of air to the exhaust gases aiding oxidation of hydrocarbons and carbon monoxide in the exhaust stream. The system does not interfere with the ability of the EGR system (if used) to control nitrous oxide (NOx) emissions.

Air Inlet For Air Pump:

Air is drawn into the pump through a rubber tube that is connected to a fitting on the air cleaner housing.

AIR INJECTION PUMP

Air Injection Pump Mounting - Typical:

The air pump is mounted on the front of the engine and driven by a belt connected to the crankshaft pulley.

The air injection system is not completely noiseless. Under normal conditions, noise rises in pitch as engine speed increases. To determine if excessive noise is fault of air injection system, disconnect drive belt and operate engine.

CAUTION: Do not attempt to lubricate the air injection pump. Oil in the pump will cause rapid deterioration and failure.

Air Pump Diagnosis:

Refer to the AIR PUMP DIAGNOSIS chart for additional information.

ONE-WAY CHECK VALVE
A check valve is located on each of the air injection downstream tubes.

Each check valve has a one-way diaphragm which prevents hot exhaust gases from backing up into the hose and pump. The check valve will protect the system if the air injection pump belt fails, an air hose ruptures or exhaust system pressure becomes abnormally high.