Ignition coils take the low voltage from the battery and amplify it with the use of magnetic fields.

That higher voltage output was then sent out to the spark plugs where it ignited the air fuel mixture inside the engine.

As the years go by ignition coils have evolved and take on many forms and upgrades.

Types Of Ignition coils:

  • Distributor-Style
  • Electric Ignition
  • Ignition Coil Packs
  • Coil On Plug Ignition
  • Waste Spark Style
  • Coil-Near-Plug (CNP)
  • Stick Coil

Choose Your DannysEnginePortal.com Help Topic Below

Ignition Coil – Coil Types – Failure Symptom Warning Signs

Coil On Plug Ignition System (COP) – Function – Failure – Diagnosis

(DIS) Distributorless Ignition System – Replace The Distributor


What Causes Ignition Coils To Failure?

If your spark plug wires have too much resistance in them or spark plugs are extremely worn out, it will cause the ignition system to work harder. When that happens, the lifespan of the ignition coil usually shortens. It’s also possible for the plastic cases of the coils to crack from being exposed to heat, or corrosion could eat away at the electrical terminals!

What Are Symptoms of Ignition Coil Failure?

So, symptoms of failed ignition coils somewhat depend on the vehicle. If a vehicle has a single coil or a coil pack feeding the entire engine, then the engine will likely not run at all when a ignition coil fails. This typically happens abruptly. Consequently, one day the car will run great, the next day it is dead in the driveway from lack of spark.

For vehicles with a coil on plug ignition system, a bad ignition coil would cause a misfire in one or more cylinders at once. The engine will still run, albeit quite powerless, and rough. Some coil on plug ignition coils actually control two cylinders with a waste spark system (as described above). In that type of system some bizarre failures can take place. A single waste-spark coil may cause just one cylinder to misfire, and other times it may cause both cylinders that it controls to misfire.

When it comes down to diagnosis of a weak or failed ignition coil, the “Check Engine Light” is the best place to start. With a scan tool, the trouble code will tell you which cylinders are misfiring. From there, you can either mist some water over the coils or swap the ignition coils from one cylinder to the next to see if the misfire moves positions on the engine. Finally, both are very simple ways of diagnosing a potentially damaged engine ignition coil.

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