Automatic Idle Speed (AIS) Motor

AIS (mounted on throttle body) is controlled by logic module. Logic module uses sensor input to determine optimum engine idle speed for any idle condition. AIS is then adjusted to allow a specific amount of air through an air by-pass on back of throttle body.

This by-pass is enlarged or restricted, as required, to meet varying engine operating conditions. This results in a change in air/fuel ratio, detected by the O2 sensor. Logic module then changes amount of fuel introduced to maintain an ideal air/fuel ratio.