Exhaust Gas RECIRCULATION (EGR): Notes
WARNING: This page is about a different car, the 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, and 1995 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
EGR system allows a predetermined amount of exhaust gas to enter cylinder with air/fuel mixture. This dilution of cylinder air/fuel volume reduces oxides of nitrogen (NOx) and helps prevent spark knock by reducing peak temperatures inside combustion chamber.
EGR system is a backpressure type. Backpressure transducer measures amount of exhaust gas backpressure on exhaust side of EGR valve and varies amount of vacuum applied to EGR valve. See Figure .
This system allows backpressure transducer to provide proper vacuum signal to EGR valve for all engine operating conditions. EGR system is controlled by an EGR vacuum solenoid using a manifold vacuum signal from throttle body.