Compression Check: Testing and Inspection

COMPRESSION INSPECTION [AJ]

Warning:
^ Hot engines and engine oil can cause severe burns. Turn off the engine and wait until it and the engine have cooled.

1. Verify that the battery is fully charged.
^ Recharge it if necessary.
2. Warm up the engine to the normal operating temperature.
3. Perform "Fuel Line Safety Procedure". Leave the fuel pump relay removed.

Warning:
^ Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
^ Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injures or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete the "Fuel Line Safety Procedure".

4. Remove the ignition coils.
5. Remove the spark plugs.





6. Install the compression gauge into the spark plug hole.
7. Crank the engine a minimum of five compression strokes and record the highest reading. Note the approximate number of compression strokes required to obtain the highest reading.
8. Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
9. The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75% of the highest reading.
^ If the compression in one or more cylinders is low or the compression difference between cylinders exceeds the maximum, pour a small amount of clean engine oil into the cylinder and recheck the compression.
- If the compression increases, the piston, the piston rings, or cylinder wall may be worn and overhaul is required.
- If the compression stays low, a valve may be stuck or improperly seated and overhaul is required.
- If two adjacent cylinders indicate low compression pressures and squirting oil on piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil and/or coolant in the cylinders could result from this condition.
10. Remove the compression gauge.
11. Install the spark plugs.

Tightening torque
9 - 20 Nm (91 - 204 kgf.cm, 79 - 177 in. lbf)

12. Install the ignition coils.
13. Install the fuel pump relay.