Compression Check: Testing and Inspection

Engine Compression Inspection

NOTE: After the inspection, you must reset the PCM. Otherwise, the PCM will continue to stop the fuel injectors from operating.

1. Warm up the engine to normal operating temperature (cooling fan comes on).

2. Turn the ignition switch to LOCK (0).

3. Connect the HDS to the DLC.

4. Turn the ignition switch to ON (II).

5. Make sure the HDS communicates with the vehicle and the PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.

6. Select ALL INJECTORS STOP in the PGM-FI INSPECTION menu with the HDS.

7. Turn the ignition switch to LOCK (0).

8. Remove the six ignition coils and the six spark plugs Service and Repair.

9. Attach the compression gauge to a spark plug hole.






10. Step on the accelerator pedal to open the throttle fully, then crank the engine with the starter motor, and measure the compression.





11. Measure the compression on the remaining cylinders.





12. If the compression is not within specifications, perform a cylinder leak down test to determine the problem area. Then check the following items, and remeasure the compression:

- Incorrect valve clearance
- Confirmation of camshaft timing
- Damaged or worn cam lobes
- Damaged or worn valves and seats
- Damaged cylinder head gaskets
- Damaged or worn piston rings
- Damaged or worn piston and cylinder bore

13. Remove the compression gauge from the spark plug hole.

14. Install the six ignition coils and the six spark plugs Service and Repair.

15. Select PCM reset in the PGM-FI INSPECTION menu to cancel ALL INJECTORS STOP with the HDS.