1980 California RX-7s and all 1986–89 models are equipped with a system for recirculating exhaust gases from the thermal reactor/exhaust manifold and introducing them into the combustion chamber, in order to lower the combustion chamber temperature and prevent the formation of oxides of nitrogen (NOx). The system consists of an EGR valve, an EGR valve solenoid, a vacuum switch and No. 1 water temperature sensor (1980 only).