In the past, most cars and trucks were made with a distributor. Part of a vehicle's overall ignition system, it lives up to its namesake by distributing voltage. Most automakers, however, have since phased out distributors in favor of a coil pack. Nonetheless, if you own a vehicle that was manufactured over 20 years ago, it may possess a distributor.
What Is a Distributor?
A distributor is an ignition component that distributes an equal and appropriate amount of voltage to the vehicle's spark plugs. Spark plugs, of course, are designed to ignite the mixture of air and gas inside the engine's combustion chamber. To perform this otherwise essential task, they require voltage. The distributor gives the spark plugs the correct voltage so that they can ignite the air and gas, thus powering the engine.
How Distributors Work
Most vehicles have a battery, which is responsible for providing electricity to their electrical components. Spark plugs are considered an electrical component because they require electricity to operate. Distributors are also considered electrical components.
There's typically a single spark plug over each of the engine's cylinders. With multiple spark plugs, problems can occur if they receive different amounts of electricity. If one spark plug receives more electricity than another spark plug, the cylinder with which it's used will generate more power. A distributor ensures that all of the engine's spark plugs receive the same amount of electricity. It takes the electricity from the battery and evenly distributes it to the engine's spark plugs.
Why Distributors Have Been Phased Out
You won't find many new vehicles with a distributor. Instead, most vehicles now use a coil pack. Distributors often suffer from timing problems. Even if a distributor sends the correct amount of electricity to the spark plugs, it may use the wrong timing. In other words, the distributor may fire some of the spark plugs at different times than other spark plugs, which can lead to performance issues with the engine.
Coil packs are less prone to errors and failure. Consisting of a collection of ignition coils, they are regulated by the vehicle's engine control unit (ECU). The ECU is a computer that monitors, as well as controls, engine processes. It tells the ignition coils how much electricity they should distribute to each spark. At the same time, the ECU controls the timing of this activity to ensure optimal engine performance.