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EM-24 < PERIODIC MAINTENANCE > COMPRESSION PRESSURE COMPRESSION PRESSURE Checking Compression Pressure INFOID:0000000009886407 1. Warm up the engine thoroughly. Then stop the engine. CAUTION: If CONSULT is not used to release fuel pressure leave the fuel pump fuse disconnected until step 7. 3. Remove the spark plug from each cylinder. Refer to EM-17, "Removal and Installation" 4. Connect the engine tachometer (not required in use of CONSULT). 6. With the accelerator pedal fully depressed, turn the ignition switch to “START” for cranking. When the gauge pointer stabi- lizes, read the compression pressure and engine rpm. Perform these steps to check each cylinder. Unit: kPa (kg/cm 2 , psi) /rpm CAUTION: Always use a fully charged battery to obtain specified engine speed. • If the engine speed is out of the specified range, check the battery liquid for proper gravity. Check the engine speed again with normal battery gravity. • If the compression pressure is below the minimum value, check the valve clearances and parts associ- ated with the combustion chamber (valve, valve seat, piston, piston ring, cylinder bore, cylinder head, cylinder head gasket). After checking, measure the compression pressure again. • If some cylinders have low compression pressure, pour a small amount of engine oil into the spark plug hole of the cylinder to re-check it for compression. - If the added engine oil improves the compression, the piston rings may be worn out or damaged. Check the piston rings and replace if necessary. - If the compression pressure remains at a low level despite the addition of engine oil, the valves may be malfunctioning. Check the valves for damage. Replace the valve or valve seat accordingly. • If two adjacent cylinders have respectively low compression pressure and their compression remains low even after the addition of engine oil, the gaskets may be leaking, or a valve in adjacent cylinders may be damaged. Inspect and repair as required. 7. Installation of the components is in the reverse order of removal. Tool number : EG15050500 (J-45402) Standard Minimum Deference limit be- tween cylinders 1,520 (15.5, 220) / 200 1,324 (13.5, 192) / 200 98 (1.0, 14) / 200 WBIA0605E |