8 Signs of a Faulty Ignition Coil

The ignition coil plays a vital yet unseen role in your MINI’s startup and performance by firing the spark plugs. As one of the key components inside the distributor or coil packs, a faulty coil can lead to frustrating issues. It’s important to understand the signs that this important part may need servicing by the experienced technicians at your MINI dealer.

8 Signs of a Faulty Ignition Coil

1. Hesitation or Misfires

One of the first signs is hesitation, stalling, or misfires upon acceleration. This occurs as a failing coil struggles to generate a strong enough spark for proper combustion in each cylinder. You may also notice rough idling.

2. Low Fuel Economy

Misfires and hesitation from a faulty coil result in unburned fuel passing through the exhaust. This wasted fuel means lower fuel economy at the pump over time. Pay attention to rapidly decreasing mpg.

3. Diagnostic Trouble Codes 

Your MINI’s onboard diagnostic system is uniquely capable of detecting problems with individual coils and generating diagnostic trouble codes corresponding to the specific coil circuit. Have any ignition-related codes checked by the expert technicians at your local MINI dealer.

4. Deteriorating Spark Plug Performance

Over time, the weak spark from a failing coil can cause spark plugs to wear out prematurely. Plugs may look wet, oily, or burned at an accelerated rate. Replacing worn plugs may not resolve issues if the underlying coil is faulty.

5. Engine Knock or Pinging Sounds

Weak sparking can sometimes allow fuel to auto-ignite outside of the engine’s timed ignition window, producing audible pinging or knock. This damaged engine components over the long haul if left unresolved.

6. Hard Starting

When trying to start a vehicle with a bad coil, the starter may crank the engine for longer than usual before it catches. This is because weak sparking can’t fully ignite the air-fuel mixture on the initial cranking attempts. It takes extra time for combustion and the engine to stabilize. Hard starting is more prevalent in colder weather.

7. Check Engine Light

The check engine light will eventually illuminate most modern vehicles with coil failure. Advanced engine diagnostics detect misfires and store diagnostic trouble codes pointing to problems in the primary or secondary ignition circuits. Trust Dash lights as another clear sign for further inspection.

8. Occasional Mild Energy Surge

In rare cases, a faulty coil may produce an unusually strong spark, potentially causing a momentary energy surge felt through the vehicle. However, surging is not a very common symptom of a coil pack issue.

Replacing faulty coils identified by auto diagnostic tools can restore proper sparking and help prevent escalating repairs down the road. Visit us today at Tom Bush MINI in Jacksonville, FL, for a coil check. Our factory-trained technicians can diagnose ignition problems and ensure your MINI’s coil packs are in good working order to avoid future misfires.

Tags: Compact Cars, Jacksonville MINIs, MINI Cooper, MINI Service
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