Variable Induction Position Sensor: Description and Operation

Electronic Engine Controls


Intake Manifold Runner Control (IMRC) Sensor (6.8L 3V)

The 6.8L air induction system improves engine performance by using the IMRC as follows:

- The intake manifold has 2 runners per cylinder, feeding each of the intake ports in the cylinder heads.
- The IMRC assemblies are located between the upper intake manifold and cylinder heads, providing 2 air passages for each cylinder.
- The valve plates are opened and closed by the IMRC electric actuator, which is controlled by PCM.
- One air passage is always open and the other passage switches from closed to open by means of a valve plate.
- Below 1,500 rpm, this valve plate is closed to improve fuel economy and emissions.

For removal and installation, refer to Intake Manifold Runner Control (IMRC) Actuator - 6.8L Service and Repair.