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Leading causes of ignition coil failures

What are the leading causes of ignition coil failures?

Some engines are known for their ignition coil failures, while the ignition coils in other comparably sized engines can run for the life of the engine. So what makes an ignition coil go bad? Here are the most common causes of ignition coil failure.

Worn spark plugs are the #1 cause of ignition coil failures

As spark plugs wear, their gap increases and that larger gap requires a much higher voltage to jump the larger gap. When an ignition coil is forced to produce peak voltage for extended periods, they overheat which degrades the insulation on the windings. That causes the ignition coil to fail.

Worn spark plug wires are the #2 cause of ignition coil failures

As spark plug wires break down their resistance to electrical flow increases. When the ignition coil fires, much of the energy of the firing voltage is lost due to the increased resistance. Just like worn spark plugs, this higher voltage required to fire the plug increases the core temperature of the coil winding, causing them to fail.

In addition to conductor breakdown, the insulation on spark plugs also breaks down, allowing the spark to fire through the insulation to the nearest ground point. Arcing causes the ignition coil to overheat and fail.

Heat is the #3 cause of ignition coil failure

The wire windings inside the coil are coated with thin lacquer insulation and the winding bundle is usually encased in epoxy. Prolonged exposure to high heat can cause the epoxy to break down, which results in internal arcing and failure.

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Posted on by Rick Muscoplat


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