1979 Federal Models

This valve is mounted in line between an intake manifold vacuum source and vacuum line of EGR system. When intake manifold vacuum exceeds 13.2-14.4 in. Hg, this valve will bleed off excess vacuum.

Fig 1: Exhaust Gas Recirculation System (Typical)

Courtesy of GENERAL MOTORS COMPANY

Fig 2: Vacuum Control Valve Flow

Courtesy of GENERAL MOTORS COMPANY