Mixture Control Valve (MCV) Inspection

1. Disconnect large rubber hose (1) connecting MCV and intake manifold. See Fig 1 . Plug intake manifold side.
2. If MCV is functioning properly, secondary air should continue to blow from MCV for a few seconds when throttle is opened completely and released quickly. If secondary air continues to blow out for more than 5 seconds, replace MCV.

Fig 1: Cross-Sectional View of Mixture Control Valve

Courtesy of ISUZU MOTOR CO.