Ignition coils Archives - UnderhoodService
The Do’s and Don’ts of Installing Spark Plugs

This article discusses the “conscious” steps you should perform during spark plug replacement.

Ignition Systems

The ignition coil is a very simple and robust circuit.

A Closer Look: Ignition Coils

OE coils are known for their high failure rates. Engine misfires, rough idle, a decrease in power under acceleration, poor fuel economy, and a check engine light are all signs of an ignition coil that has failed. Read along for more technical information on how to diagnose a failed coil, and why the original equipment

Ignition And Coil Flashover

If you see carbon tracking or “flash over” on a spark plug, boot or coil, it is not normal.

VIDEO: Why Are Ignition Coils Lubricated?

Do you know why Mercedes lubricates their ignition coils at the factory? This video is sponsored by Standard Motor Products.

VIDEO: How Much Energy Does It Take To Fire A Coil?

The condition of a spark plug can tell you a lot. This video is sponsored by Standard Motor Products.

VIDEO: Why Should You Replace All The Coils And Plugs

Not replacing them all could leave the root cause of the failure in the engine. This video is sponsored by NGK and NTK.

VIDEO: Diagnosing A Check Engine Light

What’s worse, a solid or flashing check engine light? This video is sponsored by Auto Value and Bumper to Bumper.

VIDEO: Intermittent Ignition Coil Failures

On coil-on-plug setups, the primary terminals may be located in a connector. This video is sponsored by Blue Streak.

VIDEO: What Makes For A High-Quality Ignition Coil?

Less expensive ignition coils use resins that are less resistant to vibration, heat and endless heat cycles under the hood. Taking a risk on a cheap ignition coil from an unknown source can put an engine at risk. Sponsored by Blue Streak.

Coil On Plug Ignition: The Wired Differences

For late-model vehicles, the norm is one ignition coil per cylinder, commonly known as coil on plug. The task of providing voltage potential to each spark plug is performed so reliably that it’s easy to take for granted.

Leading Causes Of Ignition Coil Failures

It may be surprising to learn that the leading causes of ignition coil failures have nothing to do with the coils themselves. Ignition coil damage is often caused by underlying issues never addressed in engine misfire repairs. Issues like spark plug gapping, leaking valve covers or moisture intrusion.