What cause ignition spark

[Lextreme II]

My friend's UZFE powered car recently caught on fire. I wonder what cause spark discharge (arc) similar to this video.

http://www.youtube.com/watch?v=4E9pNWtYJwo&feature=related

The discharges were outside of the cap and among the spark plug wires.

 

[cribbj]

Electrical energy will always choose the path(s) of least resistance to return to earth. If any part of the ignition system has a lower resistance than the spark plug, the energy will use that path to go to earth. Cracks in distributor caps, secondary leads in poor shape, worn insulation on plug boots can all present an easier path to ground than the plug under the right conditions.

It's really amazing that we don't have more car fires, considering we have all the right ingredients under the hood for a major disaster. All it takes is an itty bitty fuel leak, and an ignition system with its secondary side in poor condition.

Another strong selling point for COP's!!!

 

[Lextreme II]

Thanks John,

From this incident http://lextreme.com/forums/showthread.php?t=11073 what do u think happened? Do u think the spark arc can melt the cap and create a fire? Or do u think spark arc helped by leaking fuel?

 

[cjsupra90]

David, Just like john said, the spark will always find the easiest way to ground. I've opened hood of running cars when it totally dark out and it looks like the 4th of july under there form bad wires....

Looking at that thread, My guess is residual fuel or fuel leak and a spark arc caused that fire.