System Checking: Overview

The following difficulties may indicate a malfunctioning ventilation valve:

1. Engine stalls frequently after stops, runs rough after restart
2. Engine loses power and surges at speeds above idle.
3. Engine has rich rolling idle, produces black smoke at tailpipe.
4. Idle speed fluctuates, but engine does not stall.

Fig 1: 1961-62 POSITIVE VENTILATION VALVE

Courtesy of GENERAL MOTORS COMPANY

Fig 2: 1961 OPEN VENTILATION SYSTEM (6 CYL.)

Courtesy of GENERAL MOTORS COMPANY

Fig 3: 1962-63 OPEN VENTILATION SYSTEM (6 CYL.)

Courtesy of GENERAL MOTORS COMPANY

Fig 4: 1964-65 OPEN VENTILATION SYSTEM (V8)

Courtesy of GENERAL MOTORS COMPANY

Fig 5: 1964 OPEN VENTILATION SYSTEM (6 CYL.)

Courtesy of GENERAL MOTORS COMPANY