Air Switching Valve (ASV)
The ASV is operated by air pump pressure and by intake manifold vacuum through the vacuum switching valve. The ASV redirects airflow from the air pump to either the check valve or atmosphere.
When manifold vacuum is applied to pipe No. 1, the ASV allows air to flow from air pump to the check valve. When the vacuum switching valve directs air pump pressure to pipe No. 1, the ASV shuts airflow to air injection manifold and vents pressure to the atmosphere (air cleaner).