What causes spark plug wire to arc at coil boot?
What causes spark plug wire to arc at coil boot? The root cause is usually a misfiring spark plug. Over time a spark that is jumping can damage the plug wire or coil boot as the case may be. With the spark plug out I would advise running a compression check on that cylinder. How long does it take for a spark plug wire to arc? A connection is made to apply 12vdc to a coil. Current starts to flow but it is opposed by the induction of the coil. The voltage slowly overcomes the induction and more current flows....