Ignition coils are an electronic component as part of the vehicle’s ignition system.
The ignition coil functions as an induction coil that converts the battery's low voltage into the thousands of volts needed to create an electric spark in the spark plugs to ignite the air-fuel mixture. Back in the old days, ignition systems would use a singular canister type coil to provide for all cylinders but most modern cars now use direct individual coils for each cylinder (Ranging from 4 to 8 cylinders on). Fitted on top of the spark plugs(click HERE to read about spark plugs), it created a much more efficient spark phase. It improved fuel efficiency, emissions, performance, and diagnostics.
Though that has also brought in a new set of problems that commonly plagues not just BMWs but other modern cars as well. Issues such as misfiring, rough idling, loss of performance to name a few; can commonly be found with ignition coils to be the root of the problem. To prevent these re-occurring issues, BMW has consistently made many changes over the years. But it isn't always exactly because of a flaw in the coil's design, or bad manufacturing. There are many other reasons that can contribute to an ignition coil's failure, that doesn't have anything to do with the coil itself such as heat, electrical issues, oil contaminations and so on.
Are there any difference between BMW and OEM ignition coils?
Let's look into the meaning of OE and OEM before we continue.
OE = Original Equipment - These are the original parts from the BMW's assembly line. Made by the same manufacturer, carries the BMW logo and has met all of BMW's quality standards. It's exactly what you get from the BMW dealership, purely original parts.
OEM = Original Equipment Manufacturer - These are parts that come from the same manufacturers that supplies the parts to BMW but they are boxed in their respective brands and without the BMW logo on them. Without going through the BMW dealer network and sold directly from the manufacturer to retailers or suppliers, the price of the parts are significantly cheaper therefore you pay less for pretty much the same thing. But these parts do not go through BMW's quality control tests so the quality of the parts may vary.
So the answer is - yes and no. There isn't much of a difference between OE and OEM itself as they are essentially built the same. Other than the BMW logo, the quality tests and an important factor to all, the price!
In most cases, purchasing OEM products directly from the manufacturers hasn't posed much of an issue and many customers opt to do so.
What OEM options do I have?
If you're familiar, you would've heard about Bosch, Delphi and Eldor coils by now. They are the OEMs for BMW ignition coils but, they are not all the same.
Bosch ignition coil
Bosch was the main manufacturer for BMW's ignition coils for quite a long time, before Delphi and Eldor came along. There were many re-designs along the way, one example being when the 12138647689(Bosch 0221504470) superseded the 12131712219(Bosch 00124), due to a change in the attachment to the spark plug. When installing the 12131712219(Bosch 00124), you would hear an audible click once it's secured. This was caused by a catch mechanism in the rubber boot of the coil to establish a secure fit over the spark plugs.
It was then re-designed, resulting in the 12138647689(Bosch 0221504470) coil. This coil uses a contact spring to attach itself to the spark plug tip instead which provides better coil performance at the spark plug connecting point. The new design has been in use for many years with no issues. Though the change seemed minor, many technicians were aware simply due to the click sound they were so accustomed to.
Delphi Ignition Coil
Delphi also started manufacturing coils for BMW and they are still active and in use for many of the current BMW cars using the 12138616153 part number. They have a nice sturdy outer metal shell and are heavier than the Bosch coils. A nice touch is the use of a special epoxy to insulate the wires and keep them separate. They also use a special vacuum technique to remove air bubbles from the epoxy to avoid compromising the integrity of the insulation.
Eldor ignition coil
In early 2016, Eldor also became an OEM to BMW. The newly improved BMW coil part number - 12138657273 which is manufactured by Eldor, supersedes both the Delphi 12138616153 and Bosch 12138647689. Similar to the Delphi, it has a outer metal body but in black. The eldor coils has a snugger fit on the spark plugs and are heavier than the Bosch or the Delphi. These eldor coils are also used in some of Roll Royce's car such as the Wraith.
What this also means is that these ignition coils are interchangeable. So if you're currently using Delphi 12138616153, you may switch to Eldor 12138657273. However, it is recommended for all of your coils to be of the same part number/brand at any one time and not to use a combination as there are minor differences in each new part number/brand and to consult a professional before interchanging them.
What about aftermarket ignition coils?
Bimmerlife ignition coil
Most aftermarket ignition coils are catered for the performance enthusiast. Many of these aftermarkets are marketed to be high voltage coils, in order to be able to power higher output cars. Aftermarket brands like Bimmerlife carry such performance coils. Bimmerlife's plug and play coils(check it out HERE) employs the use of genuine Audi R8 coils with their customized harness. These coils are "smart" coils, meaning they have a built in ignitor and current is no longer carried through the Digital Motor Electronics (DME). A re-flash has to be done on the MHD flasher as well to complete the set up.
There are a wide range of aftermarket performance coils for BMWs, talk to us to find the right ones for your car.
When should I replace my ignition coils?
Ignition coils can become faulty due to quite a number of reasons. Over time the coils can start deteriorating. High temperatures and constant vibrations can lead to failure of the internal parts. Damage from leaking engine oils, condensation or other fluid leaks are very common too. Faulty spark plugs could also in turn affect ignition coils and result in premature failure.
Some common symptoms of faulty ignition coils:
This is one of the most common symptoms of faulty coils. The ignition coils plays a huge role in the ignition system, if it fails to ignite the spark plug, this causes it to misfire. Resulting in rough idling and a dramatic loss in power that can't go unnoticed. You'll feel your car sputtering and jerking when you try to accelerate. If it's bad enough, your car may even stall.
Poor fuel economy
If you're clocking way less mileage than before, this could be a sign that your ignition coil is faulty.
Check engine light on
If your check engine light is on, a workshop can assist to check on the laptop to see if there are any fault codes up for your ignition coils or in any case, check what is causing an issue.
As you can tell, there are quite a lot of factors when it comes to choosing the right ignition coils. This article is just a guideline for you to have a better understanding of the options you have. If you have any questions, do not hesitate to contact us on Whatsapp using this link https://wa.me/6597883616 or email us at email@example.com