Colt Vista 4WD L4-1997cc 2.0L SOHC (1985)
Fig. 8 Dual type EGR control valve
EGR CONTROL VALVE
The EGR Control Valve controls the flow of exhaust gasses during specific modes of operation. During high load operation, the control valve
increases EGR flow to help meet the stringent emissions standards required by law. However, during low load operation, the control valve reduces EGR
flow to help improve driveability. Two types of control valves are used.
The single type EGR Control Valve, Fig. 7, is operated by carburetor vacuum in response to throttle valve opening. EGR flow is not available at idle
or wide open throttle operation. The dual type EGR Control Valve, Fig. 8, consists of primary and secondary valves which are operated by different
carburetor vacuums in response to throttle valve opening. The primary valve controls EGR flow when the throttle valve is slightly open, while the
secondary valve controls EGR flow during wider throttle openings. EGR flow is not available at idle or wide open throttle operation.
