Concord L6-258 4.2L VIN C 2-bbl (1982)
Vacuum Gauge/Economy Meter: Testing and Inspection
Fig. 3 Typical vacuum gauge
This gauge measures iotake manifold vacuum. The intake manifold vacuum varies with engine operating conditions, carburetor adjustments, valve
timing, ignition timing and general engine condition.
Since the optimum fuel economy is directly proportional to a properly functioning engine, a high vacuum reading on the gauge relates to fuel
economy. For this reason some manufacturers call the vacuum gauge a "Fuel Economy Indicator." Most gauges have colored sectors the green sector
being the "Economy" range and red the "Power" range. Therefore, the vehicle should be operated with gauge registering in the green sector or a high
numerical number for maximum economy.
TROUBLESHOOTING
The vacuum gauge is a nonadjustable mechanical gauge. Accuracy may be tested by connecting a test vacuum gauge of known accuracy with the
existing gauge using a T-fitting. Compare the vacuum readings of the gauges and replace defective gauge as required.