Spirit L6-258 4.2L VIN C 2-bbl (1982)
Vacuum Spark Delay Valve: Testing and Inspection
Vacuum Spark Control Delay Valve
Fig 49 Vacuum Spark Control Delay Valve
1. Connect vacuum gauge to fitting at port 1, Fig. 49.
2. Connect a second vacuum gauge to fitting at port 4, Fig. 49.
3. Vacuum should be equal on both gauges when TVS is open (cold).
4. When TVS is closed (warm) and vacuum at port 1 is greater than vacuum at port 4, air from port 4 moves through unseated check valve to port 1.
5. When the TVS is closed and vacuum at port 1 decreases to less than vacuum at port 4, check valve seals and air from port 1 moves through orifice
to port 4. When the vacuum is greater at port 1 than at port 4, air can move freely through the unseated check valve. When vacuum at port 4 is
greater than at port 1, air moves through the orifice creating a delay in the flow of air through the valve.
