EGR BACKPRESSURE Variable Transducer

A vacuum bleed hole, located inside transducer, vents EGR vacuum to atmosphere until there is sufficient exhaust backpressure to close bleed hole. When bleed is closed, vacuum is routed to EGR and normal operation begins.

The EGR backpressure variable transducer modulates EGR vacuum so exhaust gas flow is proportionate to throttle opening. This is accomplished by sensing exhaust backpressure and bleeding off some of vacuum when backpressure is low. Since exhaust pressure depends on engine load, it is equivalent to throttle opening signal. The EGR backpressure variable transducer is mounted just above EGR valve.