IGNITION SYSTEM

What is it?
The various components that control the igniting of fuel in the engine's cylinders. The ignition system has two parts: the primary side (the distributor and electronic control module), and the secondary side (the ignition coil, distributor cap, rotor, spark plug wires and spark plugs). In distributorless ignition systems (DIS), there is no distributor. Each cylinder has its own ignition coil, or coils are shared between paired cylinders that are opposite one another in the firing order.

What does it do?
Once the coil generates that very powerful spark, it needs to send it someplace. That someplace takes the spark and sends it out to the spark plugs, and that someplace is the distributor. The distributor is basically a very precise spinner. As it spins, it distributes the sparks to the individual spark plugs at exactly the right time. It distributes the sparks by taking the powerful spark that came in via the coil wire and sending it through a spinning electrical contact known as the rotor. The rotor spins because it's connected directly to the shaft of the distributor. As the rotor spins, it makes contact with a number of points (4, 6, 8 or 12 depending on how many cylinders your engine has) and sends the spark through that point to the plug wire on the other end. Modern distributors have electronic assistance that can do things like alter the ignition timing.