Checking Compression Pressure
- Run the engine until it reaches normal operating temperature.
- Turn the ignition switch to OFF.
- Release fuel pressure and leave the fuel pump electrically disconnected.
Refer to FUEL PRESSURE RELEASE .
- Remove all six spark plugs.
Refer to "REMOVAL AND INSTALLATION ".
- Attach a compression tester to No. 1 cylinder.
- Depress accelerator pedal fully to keep the electric throttle control actuator butterfly-valve wide open to maximize air intake flow.
- Crank the engine and record the highest gauge indication.
- Repeat the measurement on each cylinder (steps 5 - 7).
- Always use a fully-charged battery to obtain specified engine speed. DIFFERENCE LIMIT BETWEEN CYLINDERS REFERENCE
Unit: kPa(kg/cm2 , psi)/rpm Standard Minimum Difference limit between cylinders 1,275 (13.0, 185)/300 981 (10.0, 142)/300 98 (1.0, 14)/300 - If compression in one or more cylinders is low:
- Pour a small amount of engine oil into cylinders through the spark plug holes.
- Retest compression (steps 5 - 8).
- If adding oil helps raise compression pressure, then the piston rings may be worn or damaged. If so, replace piston rings after checking piston.
- If the pressure stays low, a valve may be sticking or is seating improperly. Inspect and repair the valve and/or valve seat. Refer to " VALVE ". If the valve and/or valve seat is damaged excessively, replace as necessary.
- If compression stays low in two or more cylinders that are next to each other:
- The cylinder head gasket may be leaking.
- Both cylinders may have valve component damage. Inspect and repair as necessary.