EGR Control

A vacuum solenoid is utilized to control the EGR supply vacuum. The solenoid is controlled by the ECM in response to the engine coolant temperatures signal. When the engine coolant temperature signal indicates that coolant temperature is below 110° F, a signal from the ECM energizes the EGR solenoid blocking vacuum to the EGR valve. The solenoid is also activated during cranking and at wide open throttle. Above 160° F the EGR solenoid is deactivated and the EGR valve is actuated according to normal (ported) vacuum and exhaust backpressure signals.