The days of controlling idle speed by adjusting a few screws on the side of a carburetor are long gone. In modern fuel injection engines, the engine idle speed is controlled by modifying the idle control valve.
The idle control valve, also known as idle actuator or idle motor, is typically located on the throttle body or in the engine area, near the throttle body. The engine control module sends an electrical pulse to the idle controller, and in response, the controller’s rotary shafts move back and forth depending on the intensity of the pulse. The movement and position of the rotary shaft regulate the airflow of the throttle body, which in turn adjusts the idle speed.
A wide variety of control valves are used today, depending on the manufacturer. The position of the idle controller varies from model to model. When installing a new control valve, it is essential to consult the manufacturer’s service information. The following procedure serves only as a general guide.
- Step: Disconnect the negative battery cable (unless advised against in the manual) and unplug the electrical connection of the idle controller.
- Step: The idle controller is usually attached to the throttle body with two screws, which may require a Torx tool.
- Step: Once the idle controller is removed, clean its housing of dirt and deposits.
- Step: Replace the idle controller, screw it in, and reconnect the connector.
- Step: Reconnect the negative cable to the battery.
Check if readjustment is recommended: Most idle controllers are Plug and Play – you simply replace the old device with a new one. However, some idle controllers require readjustment, such as disconnecting the negative (ground) battery cable for 30 minutes (note the radio code beforehand).
Here are some installation videos for idle controllers with instructions: