Spark Plug Defects

SPARK PLUG DEFECTS:




1. Normal ignition voltage spike: spark plug OK.
2. Low ignition voltage spike: Small electrode gap.
3. High ignition voltage spike: Large electrode gap.

Evaluation of combustion period at idle speed:




- Normal combustion period : Spark plug OK.




- Long combustion period: Small electrode gap.




- Short combustion period: Large electrode gap.