Ignition Coil

An ignition coil is a component of the ignition system of a vehicle. As an electronic engine management part, it helps to convert the 12 volts of a vehicle into the required thousands of volts to ignite the air-fuel mixture in the engine. While older ignition systems use a single coil to spark all the cylinders, modern designs typically have one coil for each cylinder. Any problems with this part are likely to cause engine performance issues. Read on to learn more about these crucial ignition components.

Enter your vehicle’s info at the top of this page to find the right fit.

What Is an Ignition Coil Made Of?

An ignition coil is a transformer. It consists of two coils of copper wire surrounding a laminated iron core. The coil has an open magnetic circuit forming a closed loop around the windings. The coil transfers the energy from the magnetic field of the core to the spark plug to start the fuel combustion process.

Different Ignition Systems

In older vehicles, high voltage wires may run from a mechanical distributor to spark plugs. Newer ignition systems tend to use an individual coil-on-plug or coil pack, which assigns one coil to each engine cylinder or pair of cylinders. Engine issues may be caused by failed coils or spark plug cables.

Ignition System Designs

Before replacing ignition coils, you should determine whether your vehicle relies on a coil-on-plug or coil pack ignition system. Depending on which design the vehicle uses, the precise replacement procedure will differ.

Ignition Coil Problems

Coils may be the cause of problems, or problems may be caused by failing spark plug wires. Coils that must generate higher voltage will wear out faster than coils connected to wires with normal resistance. Excessive moisture can also cause coils to fail.

You may need to remove plastic covers or air intake tubing to access ignition coils. Remove the negative battery cable before disconnecting wiring harnesses and pulling off electrical connectors. Remove any retaining bolts or open a locking tab to take out a coil or pack.

For most vehicles, this part should last about 100,000 miles. You can likely check your vehicle’s service intervals for a more precise figure. Some of the benefits of replacing ignition coils include better fuel economy, generation of sufficient voltage to start the engine, and effective fuel combustion.

The signs to look for with a faulty or worn-out ignition coil include a sputtering or jerking motion when the car starts, shaking when the car is idling or in low speed, or repeated loss of power.

How to Select the Right Part

Knowing how to select the correct ignition coil is important as it ensures your vehicle is in prime working condition. That’s why AutoZone makes finding the right part easy. Simply enter your vehicle’s year, make, model, and engine to the top of this page and we will show you parts that fit.