Bremi/STI 12138611236, 20709 Ignition Coil – BMW

Ignition coils create the power needed for the spark plug to ignite the air-fuel charge in a gasoline engine’s cylinder for combustion. They are induction-style coils that amplify the 12 volts used by your vehicle’s electrical system to up to 40 kilovolts needed to make a spark strong enough for complete combustion. Some vehicles use only one or two ignition coils for the entire engine, while others use a single ignition coil for each cylinder or sometimes two.

Failed or failing ignition coils, even if producing voltage, may not be strong enough, causing a weak spark or no spark to the cylinders. When this happens, it can cause one or all the cylinders in your BMW to misfire, making the engine run rough, if at all.

Replacing the Ignition Coils in Your BMW

When replacing an ignition coil in your BMW, whether as part of maintenance or due to a failed ignition coil, it is a good idea to replace any other connected ignition components. For engines that use a distributor, you should replace the distributor cap, distributor rotor, ignition wires, and spark plugs along with the ignition coil. For engines with a single ignition coil per cylinder or a single ignition coil for every two cylinders, you should replace the ignition wires or boots and spark plugs with the ignition coils. Additionally, it is always recommended to replace all the ignition coils simultaneously.

BMW Ignition Coils.