Ignition System Functions
Spark & Ignition
Regardless of whether you need a key to start your car or not, activating the ignition is the first step you’ll take to get your car started. The ignition ignites the fuel that is in the engine’s combustion chamber at the precise moment in the piston stroke to give your car power. Essentially, your engine mixes fuel and air and brings in a spark to create an explosion that starts your car.
Your ignition switch is just the beginning in a series of components that comprise your car’s ignition system and connects to the battery. The switch is connected to an ignition coil which is connected to a distributor, distributor cap, rotor, plug wires and spark plugs. Today’s cars use an engine control unit that controls ignition timing, fuel and other factors including idle speed.
Coils & Connections
A pair of coils, known as windings, work together to move electricity the primary coil makes the spark, the secondary coil forwards it to the distributor. A third wire is connected to the positive power source and is tasked with sending information across your car, enabling the other components to become activated.
The distributor is tasked with sending electricity to the spark plugs. It spins and connects to a rotor which also spins and reaches each point that sends the spark on through to the plug wire. Each of the contact points on the distributor cap are connected to a plug wire that sends the spark to the spark plug.
Ignition Control Module
Spark plugs are threaded into the cylinder head, with the ends of each plug found atop each cylinder. With the distributor’s lead, the intake valves bring in the precise amount of fuel vapor and air into the cylinder, that creates a spark that ignites the mixture and creates combustion. An ignition control module is a tiny computer that works with the distributor to regulate the ignition system. When this computer fails it is replaced as it isn’t a part that can be fixed.
What you see in the cabin with the ignition may be different, but once you get to its inner workings, an ignition system is nearly the same across all makes and models.