Inspecting the spark plug (Honda Civic 5)

1. Inspect the electrodes and ceramic insulator:



Burning or wear can be caused by the following reasons:

• Early ignition timing
• Weakening spark plugs
• Thermal characteristics (chimney) too low.
• Insufficient cooling.

Spark plug contamination can be caused by:

• Late ignition timing.
• Oil in the combustion chamber.
• Incorrect spark plug gap.
• Thermal characteristics (heat rating) too high.
• Excessive idle/low speed RPM.
• The air purifier element is clogged.
• The ignition coil or ignition wire armor is damaged.

2. Check the electrode gap.

Adjust the gap with a suitable tool.



Replace the spark plug if the center electrode is rounded as shown below:





3. Apply a small amount of anti-seize compound to the spark plug threads and screw the spark plugs into the cylinder head with your fingers. Then tighten them to 18 N·m (1.8 kgf·m).