Burning status & FAQ
If the high voltage pulse of the ignition coil runs away with the carbon fouling , the spark plug will misfire , and the engin would have problems while driving . When overheated , the insulator nose appears become white electrode melted . The attached fouling has spot, If it is further heated , the electrode would burn away . If the temperature reaches 800oC , the insulator nose will have pre-ignition , which would harm the engine .
If the spark plug is carbon fouled , the resistor range would decrease, meanwhile the voltage of the ignition coil will decrease . If this voltage is not as high as that the normal ignition needed , the spark plug will misfire.