Exhaust Gas RECIRCULATION: Operation
This system reduces oxides of nitrogen (NOx) emissions by recirculating a controlled amount of exhaust gases back into the engine. The EGR valve is mounted on exhaust manifold and controls flow of exhaust gases. On 1975-79 models, the vacuum signal which controls the EGR valve is taken from throttle bore, allowing for exhaust gas recirculation between idle speed and full throttle. A fuel trap keeps liquid fuel vapor from entering EGR valve.