Mechanical Inspection: Compression

Engine mechanical condition can be checked using a compression gauge, vacuum gauge, or an engine analyzer capable of performing a cylinder balance test. See engine analyzer instruction manual for availability and description of relative compression feature.

On models equipped with CIS fuel injection system, check compression with engine warm, all spark plugs removed and throttle wide open. Ground coil wire from center of distributor cap to engine block. Disconnect one end of duct between airflow sensor and throttle body to disable fuel injection system. Crank engine through at least 6 compression strokes per cylinder to determine engine compression.

On models equipped with Digifant fuel injection system, use a remote starter to crank engine during compression test, not the ignition switch. If use of remote starter is not possible, remove fuel injector(s) wire harness connector. This will prevent triggering of fuel injectors during the cranking mode.

CAUTION: Triggering of fuel injectors during test cranking of engine could create a fire hazard, flooding, crankcase contamination, hydrostatic lock-up, or lubrication to be washed off of cylinder walls.