The Carbureted vehicles covered by this guide utilize an additional emission control known as the AIR system. The purpose of the system is to reduce emissions in the exhaust while quickly heating the catalytic converter during cold engine starts. The faster the converter reaches operating temperature, the quicker it can begin to reduce engine emissions.
The system operates by allowing air flow through an ECM controlled valve to the exhaust ports during a cold engine start. This additional air speeds up the reactions occurring in the catalytic converter, heating it faster for more efficient operation. Air is diverted to the air cleaner (for quieter operation) during high rpm or Wide Open Throttle (WOT) and deceleration.
Refer to the diagnostic charts at the end of this section for functional checks of the AIR system.