Expedition 2WD V8-281 4.6L VIN W EFI (1997)
Compression Check: Testing and Inspection
Gauge Check
1. Make sure the oil in the crankcase is of the correct viscosity and at the proper level and that the battery is properly charged. Operate the vehicle
until the engine is at normal operating temperature. Turn the ignition switch to the OFF position, then remove all spark plugs.
2. Set the throttle plates in the wide-open position.
3. Install a compression gauge such as Compression Tester in No.1 cylinder.
4. Install an auxiliary starter switch in the starting circuit. With the ignition switch in the OFF position, use the auxiliary starter switch to crank the
engine a minimum of five 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.
