Compression Check: Testing and Inspection
Measurement of Compression Pressure1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Release the fuel pressure. Refer to Powertrain Management; Fuel Delivery and Air Induction.
4. Remove the ignition coils.
5. Remove the spark plugs.
^ Clean the area around the spark plug with compressed air before removing the spark plug.
1 of 2
2 of 2
6. Attach a compression tester to No. 1 cylinder.
7. Depress the accelerator pedal fully to keep the throttle valve wide open.
8. Crank the 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:
Standard: 1,324 kPa (13.24 bar, 13.5 kg/cm2, 192 psi)/350 rpm
Minimum: 1,157 kPa (11.57 bar, 11.5 kg/cm2, 168 psi)/350 rpm
Maximum allowable difference between cylinders: 98 kPa (0.98 bar, 1.0 kg/cm2, 14 psi)/350 rpm
10. If cylinder compression in one or more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and retest compression.
^ If adding oil improves cylinder compression, piston rings may be worn or damaged. If so, replace piston rings after checking the piston and cylinder walls.
^ If pressure stays low, a valve may be sticking or seating improperly. Inspect and repair valve and valve seat. 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.
11. Install spark plugs, ignition coils and fuel pump fuse.
12. Erase DTC if any DTC appears.