Cylinder Compression Pressure

Ensure battery is fully charged and starter motor is in good operating condition. Remove engine cover from engine. Remove 4 ignition coils from the cylinder head cover. Remove spark plugs. Remove EFI main relay from fuse/relay block 1. Install a compression gauge into a spark plug hole. Depress the clutch pedal on vehicles equipped with manual transmission. Hold throttle in Wide Open Throttle (WOT). Crank engine through 4 compression strokes for each cylinder being tested. Measure the highest pressure reading. See ENGINE COMPRESSION SPECIFICATIONS table.

ENGINE COMPRESSION SPECIFICATIONS

Application

Specification - psi (kPa)

Normal Compression Pressure

⁽¹⁾ 218 (1500)

Minimum Compression Pressure

⁽¹⁾ 145 (1000)

⁽¹⁾	No cylinder compression reading should be less than 15 psi (100 kPa) of highest compression reading.

After testing all cylinders, install all parts removed. Compare results with the following for diagnosis:

Normal Operation

The pistons, piston rings and valves are operating normally if the cylinder compression pressure increases quickly and evenly to the compression specification.

Faulty Piston Rings

If cylinder compression is low on the first stroke or cylinder compression increases on the following strokes but does not reach the compression specification, this indicates that the piston rings are faulty.

Faulty Valves

If cylinder compression is low on the first stroke or cylinder compression does not increase on the following strokes, this indicates that the valves are faulty.