Compression Check: Testing and Inspection

1. Verify that the battery is fully charged. Recharge it if necessary, refer to Starting and Charging.
2. Warm up the engine to the normal operating temperature.
3. Stop the engine and allow it to cool for about 10 minutes.
4. Perform "Fuel Line Safety Procedures". Leave the fuel pump relay removed, refer to Powertrain Management.
5. Remove the spark plugs.
6. Install the Special Service Tool (SST) into the No.1 spark plug hole.
7. Fully depress the accelerator pedal and crank the engine.





8. Note the maximum gauge reading.
9. Check each cylinder as above.

NOTE: - Compression:
^ Standard: 1,270 kPa (185 psi) @ 300 rpm
^ Minimum: 981 kPa (143 psi) @ 300 rpm
^ Maximum difference between cylinders: 196 kPa (28 psi).

10. If the compression in one or more cylinders is low, pour a small amount of clean engine oil into the cylinder and recheck the compression.
a. If the compression increases, the piston, piston rings, or cylinder wall may be worn.
b. If the compression stays low, a valve may be stuck or improperly seated.
c. If the compression in adjacent cylinders stays low, the cylinder head gasket may be damaged or the cylinder head distorted.
11. Remove the SST.
12. Install the fuel pump relay.
13. Install the spark plugs.