Air Injection: Description and Operation

Fig. 1 Air Injection System Components (Typical):

Fig. 2 Air Inlet For Air Pump:

Fig. 3 Air Inlet And Air Pump Air Filter:

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

Fig. 4 Air Injection Pump Mounting (Typical):

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

Refer to Air Injection System Description and Operation for information.

ONE-WAY CHECK VALVES
For air injection systems: A pair of one-way check valves is used with the air injection system. The check valves are located on each of the air injection downstream tubes.

Each one-way check valve has a one-way diaphragm which prevents hot exhaust gases from backing up into the air injection hose and air injection 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.