How To Tell If The Coil Pack Is Bad?

A coil pack takes the place of the distributor on more recent cars. It is a group of ignition coils that are electronically controlled by the computer of the car and used to ignite the spark in each spark plug in the engine. Because they have no movable parts and fire far less frequently than distributors, coil packs are, in general, much more trustworthy than distributors. Coil packs typically result in a greater spark, which improves combustion and increases horsepower in an automobile’s engine.

What is Coil Pack?

A coil pack is a collection of ignition coils that the computer in the car uses to start the engine. Sparks with energy of 50,000 to 75,000 volts are generated using the battery of the car as the source of electricity. The spark plug is then connected to the coil pack by cables to receive the voltage.

In the new car’s model, the distributor takes the position of the coil pack. This is frequently due to the coil pack’s superior dependability and consistency over the distributor. Additionally, the coil pack offers a better spark, which results in a quicker and more efficient combustion as well as more horsepower.

Symptoms of Bad Coil Pack:

If there is a coil pack issue, your automobile won’t run properly. How to identify whether a coil pack is bad can be determined by looking for the typical indicators of a bad coil pack.

Flames are flowing from the carburetor, the engine is misfiring, the automobile is making louder noises than usual, and more. Blinking engine lights, backfiring, a decrease in RPMs when accelerating, the gasoline-like scent of exhaust, engine light is illuminated, the car won’t turn over. The symptoms of bad coil pack are explained in given below one by one;

Misfiring of Engine:

One of the signs of a faulty coil pack is that the engine is misfiring. Such a vehicle’s engine will misfire, when it is tried to start, making coughing, and sputtering noise. When traveling at a high speed, the car will exhibit jerking and spitting behaviors. When a car is idling at a stoplight or stop sign, an ignition coil failure will also cause vibration.

Roughly idle engine:

A further sign of a poor coil pack is the engines choppy idle. When you are driving, it seems like there is some power lacking. Whenever the coil pack malfunctions, rough idling results, thus you must address it as soon as you notice this symptom.


How To Tell If The Coil Pack Is Bad?

Backfiring from your car may be a sign of an early-stage ignition coil failure. The unburned fuel in the engine’s combustion cylinders backfires when it escapes via the exhaust pipe. If this issue is not investigated and resolved, a costly repair may be necessary. You will notice the discharge of black smoke from the exhaust pipe if your car is backfiring.

Exhaust Smoke:

When the car is operating, the exhaust smoke that comes out can also be used to identify the signs of a faulty coil pack. Instead of the usual constant stream of smoke, it just sometimes releases itself.

A drop in RPMs when accelerating:

When you accelerate, your RPMs may drop. This might happen if your coil pack is malfunctioning. While driving, keep an eye on the RPM gauge to make the determination. The engine light’s check either illuminates continuously or blinks when the vehicle is being accelerated.

Lower fuel efficiency:

Your automobile will have to consume more fuel if the ignition coil doesn’t really send enough power to the spark plugs in it. Burning the excess and unused fuel is the one way the car can continue to run. Your automobile may have coil pack issues if it is getting much less gas mileage than usual.

Engine light is illuminated:

You should examine the engine light! Typically, while scanning with a car diagnostic tool, the engine light in your dash will illuminate and the engine code will be P0351. Examining the fault code is the simplest way to determine the symptoms of an ignition coil pack. Therefore, by examining the engine light and the error code, you may identify the coil pack issue.

The car won’t start:

One of the signs of a damaged coil pack is that the automobile won’t start. Your automobile may have a coil pack issue if you attempt to start it but it doesn’t seem to be responding.


The eight symptoms listed above are signs of a faulty coil pack. You could check with your automobile to see if it exhibits any of the symptoms; if it does, it may have a bad coil pack. Taking your car to a mechanic to have it diagnosed the issue or bad coil pack and repaired the coil pack if necessary.


What occurs when a coil pack begins to malfunction?

Typically, when a coil pack is damaged, one or even more cylinders will lose spark or ignite. Misfiring is the term used to describe this. Misfiring can make the crankshaft drag and often makes the engines operate very poorly.

Why do coil packs degrade over time?

The insulating material may disintegrate and lead to internal coil failure as a result of excessive heat and vibration. Spark plugs and wires that are worn out can make the coil work harder, need more voltage, and thus dramatically shorten the coil’s operating life.

Should I replace my spark plugs and coil packs?

It varies. The spark plugs are the part that needs to be changed the most frequently along with the ignition coils. Coils can be overworked by worn spark plugs, and the effort needed to replace both parts is frequently overlapped.

How can ignition coil failure be avoided?

Your likelihood of encountering ignition coil failures can be decreased by maintaining the condition of your spark plugs. The gap where each spark plug is ignited widens as spark plugs deteriorate, necessitating a larger voltage from the coil to close the gap.

Do I need to replace each coil pack individually?

No. One coil pack serves two engine cylinders, and the defective coil pack should be the only one changed. There is no chance that one faulty coil pack will have an impact on the others.

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