Mirage L4-1597cc 1.6L DOHC Turbo (1989)
Wastegate Solenoid: Description and Operation
Waste Gate Solenoid Valve
The wastegate solenoid is used to regulate the turbo boost pressure from about 8 to 12 PSI. The ECU uses vehicle load condition inputs from the
detonation sensor and the air flow sensor to regulate the amount of manifold pressure or vacuum to the solenoid. The wastegate solenoid is spring loaded
in the closed (lowest boost) position until after the engine is started. It then will fully ground the circuit (highest boost) and leave it grounded while the
engine is running. This allows some of the boost pressure that would operate the wastegate actuator to be bled off thus allowing more boost. The ECU
does not control boost pressure it only regulates it during failures of the control components. The wastegate valve allows the excess pressure to
bypass the turbine blades.
