Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Mechanical (H4SO): Compression: Inspection
- After warming-up the engine, turn the ignition switch to OFF.
- Make sure that the battery is fully charged.
- Release the fuel pressure.
< Ref. to RELEASING OF FUEL PRESSURE , PROCEDURE, Fuel. >
- Remove all the spark plugs. < Ref. to REMOVAL , Spark Plug. >
- Fully open the throttle valve.
- Check the starter motor for satisfactory performance and operation.
- Hold the compression gauge tight against the spark plug hole.NOTE: When using a screw-in type compression gauge, the screw (put into cylinder head spark plug hole) should be less than 18 mm (0.71 in) long.
- Crank the engine by means of the starter motor, and read the maximum value on the gauge when the pointer is steady.
- Perform at least two measurements per cylinder, and make sure that the values are correct.
Compression (350 rpm and fully open throttle): Standard:
1,020 - 1,275 kPa (10.4 - 13.0 kgf/cm 2 , 148-185psi)
Difference between cylinders:
49 kPa (0.5 kgf/cm 2 , 7 psi) or less
NO RELATED
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.