System Operational Test
Install T-fitting and vacuum gauge into vacuum line at primary vacuum port of distributor. With ambient air temperature 65°F or higher, start engine and allow to idle. Vacuum reading should be zero. Increase engine speed to 1500 RPM or slightly higher. Vacuum reading should be five inches or more. Disconnect EGR port hose and plug line to carburetor, reading should drop to zero. Reconnect EGR port hose and disconnect one of the electrical leads at vacuum valve. Vacuum gauge should now read over six inches with engine speed slightly above 1500 RPM. This test indicates that system is operating properly.