Ignition coils are a vital part of your vehicle's ignition system. Their primary role is to transform the car battery's low voltage into the high voltage needed to create a spark in the spark plugs. This spark then ignites the air-fuel mixture in the engine's cylinders, allowing your car to start and keep running smoothly. When the ignition coils fail, your car may struggle to start, misfire, or lose performance. Engines require precise ignition to run efficiently, so maintaining your ignition coils in good condition is crucial for reliability, optimal fuel economy, and long-term engine health.

What Ignition Coils Do

You can think of your vehicle's ignition coils as small but powerful transformers, and each vehicle usually has one coil for each engine cylinder. Typically, your vehicle's battery provides about 12 volts, which isn't enough to create the spark needed for combustion. Ignition coils are needed to raise that voltage to a level high enough to create the spark that ignites the fuel-air mixture. The process works like this:

1. The ignition coil draws in the battery's current.
2. Copper windings in the coil create a magnetic field.
3. When the magnetic field collapses, the energy is released as a much higher voltage.
4. This voltage is sent to the spark plug, creating the spark needed to ignite the fuel and air.

Types of Ignition Coils

Ignition Coil Pack with Distributor

This is a traditional system that routes high-voltage current from a single coil pack through a distributor. The distributor then sends the current to each spark plug in the correct firing order. The ignition coil with a distributor system has more moving parts than modern systems and requires regular maintenance, such as replacing distributor caps and rotors.

Wasted Spark Coil Pack

In a wasted spark coil pack system, each coil fires two spark plugs at the same time. One spark ignites the air-fuel mixture in its cylinder, while the other occurs in a cylinder on its exhaust stroke (where it's "wasted"). This design gets rid of the need for a distributor, making it simpler, easier to maintain, and more reliable. A downside is that this system doesn't burn fuel as cleanly, which can harm the engine over time.

Coil-on-Plug (COP)

Most modern vehicles use coil-on-plug (COP) ignition systems. In this setup, each spark plug has its own ignition coil mounted directly on top of it. This reduces energy loss, improves fuel efficiency, and delivers stronger, more consistent sparks. Because each coil operates independently, diagnosing issues can be easier; however, replacement costs may be higher if multiple coils fail.

Maintenance

Ignition coils are generally durable, but like all electrical components, they can wear out over time. By carrying out the following preventative maintenance steps, you can extend their lifespan and reduce the risk of sudden breakdowns.

・Check the spark plugs regularly and replace any worn spark plugs that can put additional strain on the ignition coils and cause them to overheat and fail prematurely.
・Inspect the engine bay regularly for leaks and moisture, as these could damage the ignition coils.
・Ensure that there are no loose or corroded connections, as these could cause a drop in ignition coil performance. Also, make sure that wiring harnesses are clean and secure.
・When replacing coils, choose high-quality parts to ensure durability.
・A comprehensive engine tune-up by an automotive professional should include an ignition system check, which can prevent coil issues before they turn into costly repairs.

Signs to Replace Your Ignition Coils

A failing ignition coil can cause noticeable performance issues. If any of the following symptoms sound familiar, it may be time to replace one or more coils.

・Engine Misfires: When coils fail to deliver enough voltage, the spark plug won't fire correctly, leading to rough idling, hesitation, or stuttering during acceleration.
・Poor Fuel Economy: Without a strong enough spark, combustion is incomplete, causing your engine to burn more fuel than usual.
・Hard to Start the Engine: If your car struggles to start or cranks longer than usual, a weak ignition coil may be the reason.
・Check Engine Light Appears: A faulty ignition coil often triggers the check engine light.
・Diminishing Power: A loss of power can signal that the coils are faulty and not delivering enough voltage to the spark plugs.
・Sudden Backfires: A weak or inconsistent spark due to faulty ignition coils may cause unburned fuel to ignite in the exhaust, resulting in sudden backfires.

How to Choose the Right Ignition Coils for Your Car

Aftermarket or OEM

Original Equipment Manufacturer (OEM) coils are built to the same specifications as the parts your car came with. They're typically more reliable, last longer, and ensure proper performance.

Aftermarket coils are made by third-party manufacturers. They can be more affordable, and there are even aftermarket coils that can improve performance, but quality can vary. Poorly made ones can wear out faster or cause compatibility issues.

If long-term reliability is your priority, we recommend going for OEM parts.

Vehicle Compatibility

When buying replacement ignition coils, cross-check the engine type and Vehicle Identification Number (VIN). Also, be sure to get the correct coil system type (distributor coils, wasted spark systems, or coil-on-plug) and the correct number of coils you will need.

Installation Considerations

Ignition coil replacement is a fairly straightforward process that you can carry out on your own. Once you have your replacement coils on hand:

1. Ensure the ignition is off and the key is removed. Let the engine cool down.
2. Locate the coils by checking your owner's manual or under the hood. Coil-on-plug systems have coils mounted directly on the spark plugs.
3. Disconnect the negative battery cable to prevent any shocks.
4. Unplug the electrical connector, unbolt the coil, then gently pull it out.
5. Insert the new coil and install it by repeating the above steps in reverse, making sure it is securely fastened with bolts and that the wiring is reconnected.
6. Reconnect the battery and start the engine to test the new coil.

Where to Buy Quality New & Used Ignition Coils

Brand-new ignition coils can be found at various trusted Auto Parts dealers. For well-maintained used ignition coils at great prices, shop here with BE FORWARD Auto Parts.