Exhaust Emissions System - Exhaust Gas RECIRCULATION: Description

Exhaust gas recirculation system is used to reduce oxides of nitrogen (NOx) by recycling some exhaust gas back into the intake manifold to lower combustion temperatures. On 1976-78 models, system consists of EGR valve, thermal vacuum valve, steel pipe, and various vacuum lines. On 1979 Models, system consists of an EGR valve mounted under intake manifold, a back pressure transducer which monitors exhaust system pressure, a thermal vacuum valve which senses coolant temperature, and a vacuum control valve (if equipped).