The air-injection or AIR system is an exhaust-emission-control system that uses a low-pressure pump to inject fresh air into the exhaust system.

• It reduces hydrocarbons and carbon monoxide emissions by injecting fresh air into the exhaust gases after leaving the combustion chamber.
• The air causes the unburned and partially burned fuel to continue burning. This system reduces the amount of these pollutants and helps convert them into carbon dioxide and water.
• The air enters the exhaust manifold through the nozzles positioned opposite the exhaust ports.
• When the air hits the hot exhaust gas coming from the exhaust port, much of the hydrocarbons and carbon monoxide changes into water and carbon dioxide. The air-injection system requires no routine service except to replace the air filter if specified in the maintenance schedule. Most air pumps have a centrifugal filter which requires no service, so check the air-pump drive belt periodically for tension and wear.