240 L4-2127cc 2.1L SOHC B21A (Can) (1984)
Fig. 9 EXHAUST GAS RECIRCULATION SYSTEM, WITH THROTTLE PARTIALLY OPEN
When the throttle is partly open, Fig. 9, the opening for the E.G.R. hose moves behind the throttle. Behind the throttle there is partial vacuum which is
transmitted to the vacuum chamber of the E.G.R. valve. The atmospheric pressure in the E.G.R. valve reference chamber forces the diaphragm
backward so that the valve opens. Exhaust gas now recirculates to the intake manifold and back into the cylinders for combustion.