Intake Manifold Runner Control (IMRC) Electric Actuated System

The IMRC electric actuated system consists of a remote mounted motorized actuator with an attaching linkage for each housing on each bank. For additional information on IMRC components, refer to ENGINE CONTROL COMPONENTS . The linkage attaches to the housing butterfly plate levers. Some variations can have either 2 intake air passages for each cylinder with one passageway that is always open and the other is opened and closed with a butterfly valve plate. The other type has a butterfly valve with a small passageway that opens up into a larger size orifice when the butterfly plates are opened. The butterfly valve plates are opened and closed by an electric motor and the motorized actuator houses an internal switch or switches, depending on the application, to provide feedback to PCM indicating the butterfly valve plate position. If the IMRC system is not working correctly then a diagnostic trouble code (DTC) is set.

The motorized actuator does not energize below 3,000 RPM, allowing the linkage to fully extend and the butterfly plates to remain closed. The motorized actuator energizes above 3,000 RPM allowing the attaching linkage to pull the butterfly valve plates open. Some vehicles activate the IMRC near 1,500 RPM.

1. The PCM uses the TP sensor and crankshaft position (CKP) sensor signals to determine activation of the IMRC system. There must be a positive change in voltage from the TP sensor along with the increase in RPM to open the valve plates.
2. The PCM uses the information from the input signals to control the IMRC motorized actuator based upon RPM and changes in the throttle position.
3. The PCM energizes the actuator to open the butterfly plates.
4. The IMRC housing contains butterfly plates to allow increased airflow.

Fig 1: IMRC Electric Actuated System Diagram

Courtesy of FORD MOTOR CO.