Compression Check: Testing and Inspection

INSPECTION

HINT: If there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.

1. WARM UP AND STOP ENGINE
2. REMOVE INTAKE AIR CONNECTOR
3. DISCONNECT HIGH-TENSION CORDS FROM SPARK PLUGS

NOTICE: Pulling on or bending the cords may damage the conductor inside.

4. REMOVE SPARK PLUGS





5. CHECK CYLINDER COMPRESSION PRESSURE
a. Insert a compression gauge into the spark plug hole.
b. Fully open the throttle
c. While cranking the engine, measure the compression pressure.

HINT: Always use a fully charged battery to obtain engine speed of 250 rpm or more.

d. Repeat steps a. through c. for each cylinder.

NOTICE: This measurement must be done in as short a time as possible.

Compression pressure: 1,230 kPa (12.5 kgf/cm2, 178 psi) or more
Minimum pressure: 880 kPa (9.0 kgf/cm2, 127 psi)
Difference between each cylinder: 98 kPa (1.0 kgf/cm2, 14 psi) or less
e. If the 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 repeat steps a. through c. for cylinders with low compression.
- If adding oil helps the compression, chances are that the piston rings and/or cylinder bore are worn or damage.
- If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.
6. REINSTALL SPARK PLUGS
Torque: 19 Nm (200 kgf.cm, 14 ft. lbs.)
7. REINSTALL HIGH-TENSION CORDS TO SPARK PLUGS
8. REINSTALL INTAKE AIR CONNECTOR