Compression Check: Testing and Inspection
Measurement of Compression Pressure1. Warm up engine.
2. Turn ignition switch OFF.
3. Release fuel pressure.
4. Remove all spark plugs.
5. Disconnect distributor center cable.
6. Attach a compression tester to No. 1 cylinder.
7. Depress accelerator pedal fully to keep throttle valve wide open.
8. Crank engine and record highest gauge indication.
9. Repeat the measurement on each cylinder as shown above.
^ Always use a fully-charged battery to obtain specified engine speed.
Compression pressure: kPa (kg/cm2, psi)/300 rpm
Standard: 1,196 (12.2, 173)
Minimum: 883 (9.0, 128)
Difference limit between cylinders: 98 (10,14)
10. If cylinder compression in one or more cylinders is low, pour a small amount of engine oil into cylinders through spark plug holes and retest compression.
^ If adding oil improves cylinder compression, piston rings may be worn or damaged. If so, replace piston rings after checking piston.
^ If pressure stays low, a valve may be sticking or seating improperly. Inspect and repair valve and valve seat. Refer to Valve, Intake/Exhaust; Specifications and Valve Seat; Specifications. If valve or valve seat is damaged excessively, replace them.
^ If compression in any two adjacent cylinders is low and if adding oil does not improve compression, there is leakage past the gasket surface. If so, replace cylinder head gasket.