Grand Marquis V8-4.6L VIN V Flex Fuel (2006)
Compression Check: Testing and Inspection
Compression Test - Compression Gauge Check
WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to Fire
Suppression System.
1. Make sure the oil in the crankcase is of the correct viscosity and at the correct level and that the battery is correctly charged. Operate the vehicle
until the engine is at normal operating temperature. Turn the ignition switch to the OFF position, then remove all the spark plugs.
2. Set the throttle plates in the wide-OPEN position.
3. Install a compression gauge such as the Compression Tester in the No. 1 cylinder.
4. Install an auxiliary starter switch in the starting circuit. With the ignition switch in the OFF position, and using the auxiliary starter switch, crank
the engine a minimum of 5 compression strokes and record the highest reading. Note the approximate number of compression strokes required to
obtain the highest reading.
5. Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
6. WARNING: If equipped with fire suppression system, repower the system. For important safety warnings and procedures, refer to Fire
Suppression System.
If equipped with fire suppression system, repower the system.
Compression Test - Test Results
The indicated compression pressures are considered within specification if the lowest reading cylinder is at least 75 percent of the highest
reading. Refer to the Compression Pressure Limit Chart.
Compression Pressure Limit Chart
