F 150 4WD Pickup V8-302 5.0L (1986)
EGR Control Solenoid: Description and Operation
EGR solenoid valve assembly (dithering type)
Dithering Type
The dual EGR solenoid valve assembly consists of two dithering solenoid valves. One is a vacuum valve which supplies vacuum to the sonic EGR valve
when energized. The second valve is a vent valve which vents the EGR valve to the atmosphere when de-energized. Both solenoid valves receive
variable duty cycle signals from ECU (EEC IV) according to EGR requirements. A restrictor is added in vacuum valve inlet port to reduce its flow
compared to vent valve. So in case vacuum valve sticks open, the vent valve will be capable of venting the vacuum flow immediately without affecting
the devices being controlled.
It is used with the EGR valve in EEC IV systems.
