On-Off EGR System (Turbo)
Exhaust gases are routed through the number 2 cylinder head port to EGR valve. SeeFig 1 . Opening of EGR valve is regulated by a vacuum port in throttle valve housing. At idle, vacuum is not applied and EGR remains closed.
The EGR system opens when engine speed reaches 1900 RPM. Special size orifice is used for controlling amount of recirculated exhaust gas. The EGR operation is prevented when engine temperature is below 110°F (43°C) by the thermostatic switch.