Variable Induction System: Description and Operation

PURPOSE
The Intake Manifold Runner Control (IMRC) system improves engine performance and torque characteristics.

Intake Manifold Runner Control (IMRC):

OPERATION
The intake manifold has two runners per cylinder, feeding each of the intake parts in the cylinder heads.

One air passage is always open and the other passage switches from closed to open by means of a valve plate.

- Below 3000 rpm, this valve plate is closed to improve low speed and cold engine performance.

- Above 3000 rpm, this valve plate opens to improve high speed engine performance.

The valve plates are opened and closed by the IMRC vacuum actuator, which is controlled by the:

- IMRC solenoid.

- Powertrain Control Module (PCM).

Below 3000 rpm:

- The solenoid is deenergized.

- The vacuum actuator holding the valve plate closed is vented.

- The spring-loaded vacuum actuator pushes the valve plate open.