Normally Open Valve Without Vacuum Vent
- With engine at normal operating temperature, parking brake applied, and transmission in Park or Neutral, disconnect air supply line at valve outlet. Disconnect vacuum line at vacuum nipple.
- With engine at 1500 RPM, air should be heard and felt at valve outlet. Connect a direct vacuum line from any manifold vacuum source to vacuum nipple on valve. Air at outlet should be momentarily decreased. Air pump supply air should be heard at silencer ports.
- Reconnect vacuum and thermactor lines. If valve fails any test and air pump functions properly, replace valve.