5.9L V8
Vacuum is tapped at throat of carburetor venturi or airflow sensor to provide control vacuum to vacuum amplifier. This low vacuum signal is increased in an amplifier to a level which will operate EGR valve. Dump diaphragm compares venturi and manifold vacuum to prevent EGR operation at wide open throttle. EGR operation is mainly determined by venturi signal, but is also affected by intake manifold vacuum and exhaust gas pressure.