Warm Engine
With coolant temperature greater than 128°F (53.3°C), the 4-port PVS opens and ported vacuum is applied to the diverter valve. Manifold vacuum is also applied through a temperature vacuum switch in the air cleaner at ambient temperatures greater than 60°F (15.5°C). Air pump output is channeled to the exhaust manifold at idle, to the catalytic converter at part throttle, and vented to the atmosphere at wide open throttle.