Festiva L4-81 1.3L SOHC EFI (1989)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
Fig. 10 Idle speed control bypass air valve. 1.3L EFI models
The idle speed control bypass air (ISC-BPA) valve, Fig. 10, controls idle smoothness by regulating the throttle plate bypass air. The BAC valve
consists of the air bypass valve which functions only during cold engine conditions (below 140°F) and the idle speed control (ISC) solenoid which
operates throughout the entire engine speed and temperature range. The air bypass valve functions by sensing the engine coolant temperature supplied to
the valve, while the ISC solenoid is controlled by the ECA output. The BAC valve allows air to bypass the throttle plate to control cold engine fast idle,
hot engine idle speed and idle load corrections. The BAC valve is located on the lefthand side of the intake manifold.
