2 symptoms: change electrode and insulator guitar with a round scar

Diagnosis: This indicates that as early as the engine combustion, ignition time is premature or low octane number of gasoline, spark plugs, high calorific value of the reasons.

Symptoms 3: insulator cracked the top

Diagnosis: Generally speaking, broken insulator knock combustion is the main reason. And the premature ignition time, petrol with an octane number of low combustion chamber temperature is too high, may lead to engine knock combustion.

4 symptoms: a grey top insulator black stripes

Diagnosis: the emergence of such a block has been that spark plug leakage, the owner needs unconditional replacement parts.