Measurement of Compression Pressure
WARNING: This page is about a different variant/trim than selected.
- Warm up the engine.
- Turn the ignition switch OFF.
- Release the fuel pressure.
Refer to FUEL PRESSURE RELEASE [QG18DE (EXCEPT CALIF. CA MODEL)] or FUEL PRESSURE RELEASE [QG18DE (CALIF. CA MODEL)] .
- Remove the ignition coils.
- Remove the spark plugs.
- Clean the area around the spark plug with compressed air before removing the spark plug.
- Attach a compression tester to No. 1 cylinder.
- Depress the accelerator pedal fully to keep the throttle valve wide open.
- Crank the engine and record highest gauge indication.
- Repeat the measurement on each cylinder.
- Always use a fully-charged battery to obtain specified engine speed
.
Compression pressure: kPa (bar, kg/cm 2 , psi)/RPM
Standard: 1,324 (13.24, 13.5, 192)/350
Minimum: 1,157 (11.57, 11.5, 168)/350
Maximum allowable difference between cylinders: 98 (0.98, 1.0, 14)/350
- Always use a fully-charged battery to obtain specified engine speed
.
- 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. Refer to VALVE CLEARANCE CHECKING , VALVE SEATS . 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.
- Install spark plugs, ignition coils and fuel pump fuse.
- Erase DTC if any DTC appears. Refer to HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION [QG18DE (EXCEPT CALIF. CA MODEL)] or HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION [QG18DE (CALIF. CA MODEL)] .