Compression Check: Testing and Inspection
COMPRESSION TEST1. Before checking engine compression, check the engine oil level. Also check that the starter motor and battery are all in normal operating condition.
2. Check the DTC and note it. Use the scan tool to clear the ECM'S memory.
3. Start the engine and wait until engine coolant temperature reaches 80 - 90°C (176 - 205°F).
4. Disconnect the fuel pump connector.
5. Turn off engine and disconnect the spark plug cables.
6. Remove the spark plugs.
7. Disconnect the Ignition Coil connector.
8. Crank the engine to remove any foreign material in the cylinders.
9. Insert the compression gauge into the spark plug hole.
10. Depress the accelerator pedal to open the throttle fully.
11. Crank the engine and read the gauge.
Standard value: 1275 kpa (13.0 kg/cm2, 185 psi)
Limit: 1128 kpa (11.5 kg/cm2, 164 psi)
12. Repeat steps 9 to 11 over all cylinders, ensuring that the pressure differential for each of the cylinders is within the specified limit.
Limit: Maximum 98 kpa (1.0 kg/cm2, 14 psi) between cylinders
13. If a cylinder's compression or pressure differential is outside the specification, add a small amount of oil through the spark plug hole, and repeat steps 9 to 12.
1) If the addition of oil makes the compression to rise, it is likely that there may be wear between the piston ring and cylinder wall.
2) If compression remains the same, valve seizure, poor valve seating or a compression leak from the cylinder head gasket are all possible causes.
Tightening torque
Spark plug: 19.6 - 29.4 Nm (2 - 3 kg-m, 14.5 - 21.7 ft. lbs.)