Vacuum Control Valve

1. Connect a vacuum tester with Y distributor to vacuum amplifier line (line with check valve) and check vacuum with engine idling.
a. With an engine speed of 680 ± 20 RPM, vacuum reading should be 360 - 410 mbar.
b. Turn ignition switch to OFF position.
c. Regulating linkage should be resting against its full load stop and zero inches of vacuum should be noted.
d. If not, check vacuum line routing, vacuum pump and vacuum control valve, repair or replace components as necessary.

2. Check supply vacuum (above 700 mbar), and vacuum vent line for restrictions.
a. Adjust vacuum control valve if not within specification.
b. Replace vacuum control valve if necessary.