Golf GTI L4-1984cc 2.0L DOHC (9A) (1990)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
Idle Stabilizer
Idle Stabilizer Diagram
The idle stabilizer valve, which is located in the bypass pipe, maintains the appropriate idle speed for various engine operating conditions.
Idle Stabilizer Valve
The idle stabilizer is a single winding rotary type valve. It consists of a small single winding electric motor, a rotary valve and return spring attached to
the motor's armature.
The CIS-E Motronic control unit compares the actual engine speed with programmed speeds for various conditions (A/C on, A/T selector lever in Drive,
etc.).
The CIS-E Motronic control unit calculates the amount of time the motor winding is energized (duty cycle %), working against the return spring. The
amount of bypass air and the idle speed is determined by the position of the rotary valve in the idle stabilizer.