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 1975-79 models, system consists of an EGR valve, a backpressure transducer (if equipped), a thermal vacuum valve, and a vacuum control valve (if equipped).

In 1974 models, 2 different EGR systems are used. On non-California models, the EGR system consists of pipes connected to exhaust system and intake manifold, an EGR valve, and a vacuum hose connected between EGR valve and carburetor.

On 1974 California models, the EGR system consists of pipes connected to exhaust system and intake manifold, regulating valve, shut-off valve, and vacuum hoses connected to intake manifold and ported vacuum port on carburetor.