1. What Is an Ignition Coil? The ignition coil functions as part of the ignition system, alongside the switch battery, alternator, spark plugs and distributor. Your vehicle's ignition coil converts the low current from a car battery into enough power to ignite the fuel and start the engine. When there is a problem with an ignition coil, it can cause a range of mechanical and performance issues. 2. Types of Ignition Coils: Distributor coils: This type of ignition coil uses a mechanically driven distributor mechanism. It’s usually found on older vehicles and was very common until the 1990s. .