Compression Inspection
WARNING:
Hot engines and oil can cause severe burns. Be careful not to burn yourself during removal/ installation of each component.
- Verify that the battery is fully charged.
- Recharge it if necessary.
- Warm up the engine to the normal operating temperature.
- Stop the engine and allow it to cool off for about 10 min.
- Relieve fuel pressure. See FUEL PRESSURE RELEASE under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Leave the fuel pump relay removed.
- Remove the ignition coils. See IGNITION COIL REMOVAL/INSTALLATION .
- Remove the spark plugs.
- Connect a compression gauge into the No. 1 spark plug hole.
- Fully depress the accelerator pedal and crank the engine.
- Note the maximum gauge reading. See Fig 1.
- Inspect each cylinder as above.
- 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 the compression in adjacent cylinders stays low, the cylinder head gasket may be damaged or the cylinder head distorted and overhaul is required.
- 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.
- Disconnect the compression gauge.
- Install the spark plugs.
Tightening Torque
15-22 N.m {1.5-2.3 kgf.m, 11-16 ft.lbf}
- Connect the ignition coil connector.
- Install the fuel pump relay.