Grand Marquis V8-255 4.2L (1982)
Air Injection Control Valve: Testing and Inspection
Thermactor Vacuum Vent Valve
1.
If necessary, remove air cleaner assembly.
2.
Disconnect vacuum tubing or connector block from valve, noting location of tubing. It may be necessary to remove valve from bracket or air
cleaner tray to gain access to vacuum ports on valve.
3.
Connect the black vacuum port to a manifold vacuum source.
4.
Connect an external vacuum source to white body vacuum port.
5.
With engine idling in neutral, apply 10 inches Hg vacuum to white port and trap. If vacuum cannot be obtained, replace valve.
6.
Remove manifold vacuum source line from black port. The trapped vacuum should drop to zero. If not, replace valve.
