Compression check
1. Warm up the engine well. Then turn it off.
2. Relieve the fuel pressure as follows:
- a. Remove the rear seat assembly.
- b. Open the inspection hatch cover
- c. Disconnect the connector from the fuel level sensor, fuel filter and fuel pump assembly and start the engine. See Chapter Accelerator, fuel system and exhaust system.
- d. After the engine stalls, crank it two or three times and release all fuel pressure.
Caution: After relieving fuel pressure and until the compression test is completed, leave the connector disconnected.
3. Remove the ignition coils and spark plugs from all cylinders. See sections "Ignition coil" and "Spark plug (with platinum tip)".
4. Connect the tachometer (not required when using CONSULT-II tester).
5. Screw the compression gauge (1) into the spark plug hole using an adapter.
Diameter 20 mm.
Use a compression tester adapter with a tip diameter of less than 20 mm. Otherwise, it may get stuck in the cylinder head when unscrewing.
6. Fully depress the accelerator pedal, turn the ignition key to the "START" position and turn the crankshaft. When the compression gauge needle settles, read the compression pressure and engine speed. Repeat the measurements on all cylinders.
kPa (kg/cm²)/350 rpm
| Engine | CR14DE |
| Standard | 1383(14,1) |
| Minimum | 1187(12,1) |
| Maximum cylinder spread | 98(1,0) |
Caution: Always use a fully charged battery to achieve the required engine speed.
If the engine speed is different from the norm, check the specific gravity of the electrolyte in the battery. Check the engine speed again with the normal density of the electrolyte.
If the compression pressure is below the minimum value, check the valve clearances and combustion chamber related components (valve, valve seat, piston, piston ring, cylinder walls, cylinder head, cylinder head gasket). After checking, measure the compression again.
If some cylinders have low compression, pour a small amount of engine oil into the spark plug hole of that cylinder and recheck the compression.
If the compression increases after adding engine oil, the piston rings may be worn or damaged. Check the piston rings and replace if necessary.
If the compression pressure remains low despite adding engine oil, the valves may be faulty. Check for damage to the valves. Replace the valve or valve seat, respectively.
If the compression pressure in two adjacent cylinders is low and remains low even after adding engine oil, there is a gasket leak. In this case, replace the cylinder head gasket.
7. After completing the inspection, install the removed components in the reverse order of removal.