How to Detect a Failing Ignition Coil in a BMW

Representing the pinnacle of refinement and sophistication, BMWs are the perfect vehicles for professionals and go-getters. However, if neglected, even vehicles produced with the highest-quality parts will start to fail. One such failure common amongst BMW is ignition coil failure. With this in mind, in this article we will learn what the ignition coil does, why it fails, discuss the symptoms of its failure, and advise you where to go for help with this issue.

What is the ignition coil and what does it do?

The ignition coil looks like a silver tube that connects to your engine via a black plastic aperture. At its core, the ignition coil is a transformer. Its purpose is to convert low voltages into high voltages. The high voltage output is used to power spark plugs, which released this electricity in a spark that ignited the pressurized air and fuel mixture inside the engine. These sparks both start and maintain the combustion cycle, allowing you to drive your BMW. Therefore, if the ignition coil fails, your BMW’s engine will not function.

What causes the ignition coil to fail?

Knowing the causes of ignition coil failure will help you to detect when an issue has occurred. The common causes of failure are as follows:

1. Defective Voltage Supply

This type of failure tends to be caused by either an overload or excessive wear upon the ignition control unit. It can also be caused by faulty wiring and battery weakness.

2. Mechanical Damage

Failure of the valve cover gasket, damaged insulation, and leaking engine oil are all examples of mechanical failure. These can harm your ignition coil.

3. Short Circuits

When the ignition coil overheats, usually when old or faulty, then short circuits are likely to occur. This can wreak damage to your electrical system and cause costly repairs.

4. Contact Faults

The leading causes of contact faults are debris build up, engine washing, and high humidity or moisture buildup under the hood.

Ignition Coil Failure Symptoms

Symptoms of ignition coil failure are the main way you will be able to detect an issue. Knowing the signs associated with ignition coil problems will help you to accurately narrow down your suspicions.

1. Poor Fuel Efficiency and Low Gas Mileage

The are many reasons why your BMW may not be achieving the same miles per gallon that it used to, and one such culprit is your ignition coil. This is because your engine and its systems are trying to compensate for the failed part.

2. Ignition Misfires and Stalling

As we’ve learned, your ignition coil is chiefly responsible for insuring the spark plugs are able to ignite the fuel in the engine. Therefore, if the coil has developed faults, then ignition may be a struggle or fail to happen at all, which will increase the risk of misfires or stalling.

3. A Struggle to Start

On a similar note to the previous point, you may notice your BMW doesn’t start the first time and may need several attempts to get the engine running. This should be seen as a serious issue and should be dealt with swiftly to prevent the coils from suddenly falling entirely, leaving you stranded.

4. Overheating Engine

One of the leading causes of premature engine failure is overheating. Therefore, if you’ve struggled with overheating recently, or noticed temperature spikes within your engine, you might need to check your coil for damage.

5. Engine Vibrations

A noisy, juddering engine is a clear sign of a problem somewhere within the engine system. It can also cause further issues too, such as with the ignition coils because of vibrations damaging the delicate inner workings.

6. Spark Plugs

As they work directly with the ignition coil, if the spark plugs fail, then they can cause your ignition coil to fail as a result.

Professional Automotive

Professional Automotive of Marlborough, MA, is hand to help you with any problems your BMW might develop. We are open Monday through Friday. Our dedicated team of ACE Certified technicians will work tirelessly to ensure all repair work is completed in a timely manner. We offer free loaner cars and are so sure of the quality of work we produce that we offer a 24-month/24,000 guarantee on all parts and labor as a guarantee!

Call our team today to see how we can help you and your BMW with all your servicing and maintenance needs.