Cylinder Compression Pressure

The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions. Ensure the battery is completely charged and the engine starter motor is in good operating condition. Otherwise the indicated compression pressures may not be valid for diagnosis purposes.

1. Clean the spark plug recesses with compressed air.
2. Remove all spark plugs from engine.
3. Secure the throttle in the wide open position.
4. Disable the fuel system.
5. Remove the Auto Shutdown (ASD) relay from the Power Distribution Center (PDC). See Figure . PDC is located in engine compartment.
6. Insert compression pressure gauge and rotate the engine with the engine starter motor for three revolutions.
7. Record the pressure on the 3rd revolution. Continue the test for the remaining cylinders.
8. For compression specifications, see COMPRESSION SPECIFICATIONS  table.