Intake Manifold Runner Control - 2.0L (VIN P), 2.5L (VIN L), Windstar 3.8L (VIN 4), & 4.2L (VIN 2)
On 2.5L, 3.8L & 4.2L engines, 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 located between intake manifold and cylinder head(s). See Fig 1-Fig 5 . On 2.0L, IMRC uses a motorized actuator mounted directly to a single housing, between intake manifold and cylinder head, without use of a cable or linkage. 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 less than 3000 RPM, electric actuator will not be energized, allowing IMRC butterfly valve plate(s) to remain in closed position. When engine speed is approximately 3000 RPM or more, electric actuator is energized, causing butterfly valve plate(s) to the open position to improve high speed engine performance. Some applications will activate IMRC butterfly valve plate(s) when engine speed is about 1500 RPM.