Intake Manifold Runner Control - 2.0L (VIN P), 2.5L (VIN G & L), 3.8L - Windstar (VIN 4) & 4.2L (VIN 2)
Intake Manifold Runner Control (IMRC) system consists of a remote mounted electric actuator with an attaching cable or linkage to operate the housing butterfly valve plate levers for each housing on each bank. See Fig 1. PCM uses a positive change in Throttle Position (TP) sensor along with the increase in engine RPM from Crankshaft Position (CKP) sensor to open butterfly valve plates.
IMRC housing is an aluminum casting with 2 intake air passages for each cylinder. One passage is always open and the other is opened and closed with a butterfly valve plate(s). IMRC housing uses a return spring to hold butterfly valve plate(s) in closed position. Electric actuator houses an internal switch or switches, dependent on application, to provide feedback to PCM indicating butterfly valve plate(s) position.
When engine speed is below 3000 RPM, electric actuator will not be energized, allowing IMRC butterfly valve plate(s) to remain in closed position. When engine speed is about 3000 RPM, electric actuator is energized, causing butterfly valve plate(s) to the open position. Some applications will activate IMRC butterfly valve plate(s) when engine speed is about 1500 RPM.