2.6L 4-Cylinder
The dual EGR system has primary and secondary valves which respond to different carburetor vacuums in response to throttle opening. EGR operation is suspended at idle and wide open throttle.
The primary valve controls EGR flow at relatively small throttle opening angles. The secondary control valve allows recirculation of exhaust gas into the intake mixture at larger throttle opening angles.
Vacuum applied to the dual EGR control valve is controlled by a thermo valve. The sub-EGR valve is directly opened and closed with motion of the throttle valve though mechanical linkage.
Two thermo valves sense coolant temperature at the intake manifold and prevent operation of the dual EGR valve below the preset temperature of the thermo valve.