Ignition Coil Packs (Everything to Know)

Are you having a hard time trying to figure out why your car doesn’t start up when you go to start in the morning? Or maybe when you’re exploring the roads, it doesn’t appear to possess the same amount of power, energy, and grunt as you do? One possible cause could be the Coil Pack.

The ignition coil pack inside your car is a crucial component that is an important part of the ignition system. If the coil pack isn’t functioning properly, the ignition system won’t function, and your car won’t start.

While all the components of your vehicle are essential and need to be in sync to perform to a high degree, the coil pack may be among the most vital components involved in starting your car and engine.

In this electronic coil pack, the ignition coils are controlled electronically by the car’s main computer.

The most important purpose of a coil pack is to produce an electrical spark that starts the ignition process. Once the voltage has been released through the cable to the spark plugs, a burning process begins.

In most advanced cars, the coil pack is used to replace the distributor. Due to its durability and stability, coil packs are usually preferred over distributors.

Additionally, the coil pack has greater spark, resulting in greater combustion efficiency and higher horsepower.

What Is An Ignition Coil?

Ignition coils are spark coils whose purpose is to produce a spark or high voltage (measured in Volts) through the use of electricity.

A car’s ignition coil turns a low-voltage current from the battery into a high voltage to ignite sparks in your engine’s spark plugs, which then help combustion occur so that your car can start.

During the ignition process, the electric spark generated by the high voltage is a quick electric discharge that occurs as a result of an ionized and electrically conductive channel.

The electricity spark could be visible within the ignition plugs.

Electrical current from the ignition coil is delivered to the engine’s combustion chamber by spark plugs.

When the compressed air and fuel mixture are ignited by the spark, they can keep the pressure in the engine for combustion and maintain the proper amount of pressure.

One of the most likely reasons for the ignition coil to fail is an inadequate spark spacing between the spark plugs.

How Does A Coil Pack Work?

The ignition system of a vehicle consists of the ignition coil (which consists of the coil pack), the ignition switch, battery, spark plugs, alternator, and distributor 

As a device that transforms high energy into low energy, the ignition coil is basically a step-up transformer in your car that makes your car’s engine easier to start by boosting the 12V power from the battery to about 20 Kv to 40Kv so that the car can be started.

The ignition coils in your vehicle are responsible for causing the spark plugs to ignite compressed fuel.

Once the ignition coil is activated, it sends a surge of energy to a much more tightly wound internal coil that then changes this current into an extremely high voltage necessary for the ignition of these forced explosions inside the pistons so as to propel them (and subsequently your engine) in order to move forward.

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Symptoms Of A Bad Coil Pack

Symptoms of a bad coil pack

If your coil pack fails, the car won’t work properly. Here are some symptoms that can help you determine if the coil pack is failing and or has failed.

1. The Engine Is Misfiring.

If you’re trying to start your vehicle and it seems as if the engine isn’t firing correctly, not starting at all, or is producing abnormal noises like sputtering or coughing, it’s possible that one of the spark coil packs has failed.

If you feel that your car is jerking while driving at very high speeds or when your car is stationary, an ignition coil that is faulty might be the cause.

2. The Engine Is Idling Roughly

Another sign that your coil pack is failing is a rough or jerky idle of the car’s engine. It may feel like the engine is losing power while you’re driving; this can indicate that the coil pack is faulty.

It’s best to have your car looked at by a mechanic as soon as possible if you notice this symptom.

3. Backfiring

If a car backfires, the coil pack may soon fail. A misfire occurs when fuel is not burning in the engine’s combustion chamber, which then either goes unused or escapes via the exhaust pipe.

When your car backfires, it could lead to excessive wear and tear of the motor parts.

It will become apparent by the thick black smoke coming from your vehicle’s exhaust pipe, which will soon develop into more expensive repairs in the future if not immediately fixed.

4. Continuous Smoke From The Exhaust Pipe

Another sign that you need a new coil pack is when there’s plenty of exhaust smoke coming from your vehicle.

If the smoke you see is coming out in “bursts” or short, frequent spurts – it could be a sign that you need a replacement coil pack because yours isn’t functioning properly.

However, if your car emits an exhaust stream of continuous smoke, it may be an indication that something else within your vehicle’s engine is going wrong.

5. A Drop In RPM During Acceleration

If your ignition coil pack is faulty, you might encounter a drop in RPM as you accelerate.

The easiest way to tell this is by viewing the RPM gauge whilst driving and finding that it continuously flashes or intermittently stays on for a substantial amount of time.

6. Lower Fuel Economy

If your car’s ignition coil is damaged, and the spark plugs are not receiving enough power, you may have to burn more fuel to continue operating it.

If your vehicle is getting significantly lower gas mileage than usual, it might be due to issues with the coil pack.

7. Engine Light Comes On

When your coil pack fails, the engine light will illuminate on your dashboard, and if you use an auto diagnostic tool, a P0351 Engine Code will appear.

Look for error messages in your engine light to discover the cause of a coil pack issue.

By reading your vehicle’s engine light, you should be able to diagnose a problem if you see an error message.

8. The car won’t start

If your car won’t start after you try to start it, it is probably suffering from a coil pack issue.

As soon as you notice symptoms such as those outlined above in your vehicle, take steps to ensure that your car’s ignition coils are working properly.

Use the multimeter inside your vehicle’s toolbox, then perform the following steps to examine your ignition coils.

How to Test Your Coil Pack

How to Test Your Coil Pack

Step 1.

Open the hood of your car and disconnect the negative battery cable from your car’s battery. Locate your vehicle’s coil pack by following the spark plug wires from the spark plug to the coil pack.

Step 2.

Each spark plug wire should be disconnected from the coil pack one at a time. Keep track of each wire by labeling it. Remove the coil pack from the engine bay after disconnecting the electrical connectors using a ratchet and socket.

Step 3

Measure the coil pack’s primary resistance with an ohmmeter. The ohmmeter should be set to 10 ohms. One lead should be attached to the center prong of the coil pack’s electrical connector, while the other lead should be attached to the terminals of the spark plug. Ideally, the ohmmeter should read below 2 ohms. Have the coil pack replaced if the readings are over 2 ohms.

Step 4

The secondary resistance of the coil pack should be measured. The ohmmeter should be set to 20,000 ohms. Connect both leads to each spark plug terminal. There should be a reading of between 6,000 and 30,000 ohms on the ohmmeter. The coil pack should be replaced if the reading is over 30,000 ohms or under 6,000 ohms.

Make sure all electrical connectors are connected to the coil pack and that it is reinstalled in the engine bay. Ensure that the spark plug wires are plugged into the coil pack in the correct order. The negative battery cable should be connected again and the hood closed.

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The amount you pay for an ignition coil replacement is contingent on your decision to change the ignition coil yourself or hire a professional mechanic to change it for you.

Follow this guide to learn how to replace your ignition coil yourself.

How to avoid a faulty Coil pack

Follow the steps below to ensure that your coil is operating efficiently and effectively:

1. Checking The Regularity Of Your Spark Plugs

As earlier mentioned, bad spark plugs can cause extra strain on the car battery that may block the electrodes of a plug, disrupting ignition and eventually shortening the life of the coil pack.

To prevent this from happening, always make sure the spark plugs are in good working condition.

2. Examine The Sasing Of The Coil To Check For No Oil Leaks.

Keeping track of the wires that link the coil to the electrical system will help you identify potential problems before they get worse.

3. Regularly Perform Scheduled Service Checks

You should pay attention to the manufacturer’s instructions for ensuring that your vehicle is in perfect working order by performing regular maintenance.

Frequently Asked Questions

Can you drive with a bad coil pack?

There is a possibility to drive with a damaged Coil pack, but it’s not recommended. If you drive with a damaged coil pack you could harm other components of your car’s engine.

Are coil packs and spark plugs the same?

Although the spark plugs and the ignition coil don’t work the same, they play a vital role in the ignition system. In the case of an ignition coil, it converts the battery’s power and produces enough energy to spark the spark plugs to ignite each cylinder of the engine.

Is it easy to replace a coil pack?

It is possible to replace a damaged ignition coil fairly quickly at home; however, keep in mind that you’re dealing with high voltages, and you should disconnect your battery before starting.

Can you replace just one coil pack?

There is a possibility to replace just one defective coil pack. But you should know that if one of the coils gets bad, the remaining coils may eventually fail as well.

Can a coil pack fail suddenly?

When the coil is just beginning to get damaged, it could send intermittent electric currents to the spark plug. This is the reason why you might normally be driving alright, but suddenly encounter problems later.

What happens when the coil pack starts to fail?

One of the most frequent symptoms associated with a defective ignition coil is issues with engine performance. The problem with the coils could result in the vehicle having misfires, slow idle, a decrease in acceleration and power, and a decrease in the mileage of gas. In certain instances, the performance issues may even lead to the vehicle slowing down.

Can a coil pack ruin a spark plug?

A faulty ignition coil pack can cause the ignition to fail, resulting in the spark plugs failing. Make sure to replace the spark plugs and when changing the ignition coil. This will help restore the efficiency and power of the fuel.

Where is the coil pack located?

A coil is a set of coils that are combined (molded) together into one piece. It is attached directly to the spark plugs in the same way as the spark plugs that are part of the COP system. The coil packs are placed just above the motor cam cover.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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