EGR Time-Delay Device
On most engine models, a time-delay device is incorporated into the EGR system which works in conjunction with the idle enrichment system to improve engine starting and performance. This system consists of an electronic timer and either one or two vacuum solenoids. The electronic timer energizes the solenoid(s) during starting and for 35 seconds thereafter. When the solenoid(s) energize(s), vacuum to the EGR amplifier is cut off, thereby stopping exhaust gas recirculation.