What Do Spark Plugs Do?

Knowing how does a spark plug faction to run your vehicle well and smoothly

Spark plugs appear as bolts and are used in the vehicle to produce a spark necessary for the ignition of the air and fuel mixture.

The nature of the spark provided needs to meet a specific threshold for the optimal performance of the engine.

Therefore, you should ensure the spark plug is in excellent condition as this will guarantee a good spark being produced.

By the way, do you know what do spark plugs do? They are usually connected to the ignition coil and generates high voltage. This voltage is required for the spark to burn the air and fuel mixture in the engine cylinder.

The electric energy transmitted through the components of the spark plug creates a spark.

This spark will ignite the air and fuel mixture, and this will cause combustion that will start the car.

This will then put the pistons of the engine in motion, and the vehicle will power up and work effectively and efficiently.

You should also know that the spark plug is in use from the ignition to when the car is switched off.

How Does The Spark Plugs Work?

Fuel moves from the gas tank and is pumped passing the fuel lines and makes its way to the fuel injectors.

Simultaneously, oxygen is being sucked through to the cylinders by the cold air intake portion.

What happens is that mixture containing the air and fuel will be mixed and become a highly combustible state. This is then injected to the cylinder.

At this time the spark plug will produce a spark that will ignite and tiny explosion will occur.

This will happen severally when the car is on; approximately at the rate of one thousand per one-minute interval.

The Types Of The Electrode

The spark plugs are made of different materials for the electrode. This usually marks the performance of each of the types of spark plugs.

You should be aware of the facts as far as the electrodes are concerned to ensure you get the best out of your spark plug.

You can work with either of the following spark plug electrodes:

  1. Copper Electrodes: These types of electrodes are the best option to go for if you are using an engine that is either modified or is a high performing. It is preferred due to high conductivity when compared with other types of electrodes.
    The only shortcoming is that you might need to replace it soon due to its inferior lifespan when compared with the iridium and platinum electrodes. They are also quite affordable and are the best choice for the high octane racing engines.
  2. Iridium Alloy Electrodes: One of the good things about these types of spark plugs is that they are long lasting. They have a high melting point and would last for more than 40000 miles.
    They have an inferior conductivity rate. You will also get them being sold at a higher price than the copper electrodes.
  3. Platinum Electrodes: These too are long lasting electrodes and have the ability to resist corrosion. You should get it if you have a new vehicle.

Selecting The Right Heat Range

Unlike what people know is that spark plugs do not produce heat, rather they conduct away heat from their working environment.

They transfer heat from the tip of the plug that is either copper, iridium or platinum. The rate at which this heat is transferred is determined by the length of the insulator mass.

This means that a plug with a longer insulator mass is designed with a hot heat range. The tip of the plug needs to be at the right temperature for it to work well.

It also needs to be at a lower temperature to avoid complications that arise from pre-ignition and knocking of the engine.

You need to adhere to the specs indicated by the factory when it comes to the heat range. This is because you can’t change the operating temperature of the burning of the fuel.

What Do Spark Plugs Do When They Go Bad?

The following are signs that will be seen when the spark has been damaged.

  1. The car will consume fuel at a higher rate than before: This might be the case if you are using spark plugs that are either dirty or are fouled with either carbon or oil deposits.
    As such, you will need to fuel your vehicle more often than it was the case before they got damaged.
  2. Bad spark plugs would be weak when it comes to the acceleration of the vehicle: You will notice this when you step on the gas pedal, and the acceleration from the car is not average. The bad spark plugs might just be the ones to blame for this situation.
  3. Poor starts: You may notice that your vehicle’s springs are not as smooth as they were initially. If all other factors, such as the battery, are in good condition, then the spark plugs might be damaged and hence unable to provide the required spark during ignition.
  4. Misfiring of the engine: This is usually the case if the gap on the spark plug is not verified when it gets altered.
    As such, the spark produced is too weak to fire appropriately and hence the occurrence of misfiring.
  5. Condition of the idling of the vehicle: You can put your vehicle in idling and be keen on the type of idling the engine it has.
    Comparing the engine of a vehicle with good spark plugs and that with bad ones, you will notice a significant difference.
    For the bad spark plugs, the engine usually idles quite rough and not smooth and steady as it should be like in the case of using spark plugs in good condition.

What Do Changing Spark Plugs Do?

Changing the spark plugs in your vehicle is one way to ensure that they are working in an efficient manner when they are installed in the car.

This is because, with a new spark plug installed in the vehicle, it will be in a better position to provide the required spark for the best performance of the vehicle.

A new spark plug will also guarantee top performance as it will not be affected by wear and tear that makes them less capable of their work.

This will ensure that fewer emissions are let out and that you don’t waste too much due to poor fuel emission.

You will also not have to deal with misfiring of the spark plugs that becomes an issue that affects the smooth running of the car when you are on the road.

When you change your spark plugs when it is time to do so, you will be able to realize the smoothest and efficient starts when you ignite the vehicle.

Other changes that a new spark plug comes with are fewer emissions to the environment as more fuel will be ignited. This is in the combustion chambers of the vehicle’s engine.

What Do Upgraded Spark Plugs Do?

You should consider upgrading the spark plugs in the engine of your vehicle to enjoy either of the following benefits.

  1. The upgraded spark plugs are designed with features that improve their efficiency and thus make them less vulnerable to wear and tear.
    As such, the upgraded spark plugs will be able to last for longer than the other ones, which normally have an inferior lifespan.
  2. Upgraded spark plugs will ensure the engine is at optimal performance all of the time. You might notice that the simple and ordinary spark plugs are always misfiring due to one issue or another.
    This is not the case for the types of spark plugs that are designed with superior and advanced technology.
  3. With the upgraded spark plugs, you will be able to realize fuel efficiency when it comes to consumption as well as less harmful emissions to the environment.
    This is because the advanced spark plugs do not cause incomplete combustion that will lead to the emission of harmful substances to the environment through the exhaust pipes of the vehicles.
  4. An upgraded spark plug would be of great use when the temperatures get too cold. This is because they are designed to provide optimal performance even when the conditions are so harsh as when it gets too cold in the morning.
  5. The upgraded spark plugs will protect other parts of the component of the engine in which they are in use. You may realize that with inferior types of spark plugs, the misfire, and this affects other components that might be too costly to repair.
  6. The upgraded spark plugs bring the best out of modern cars as they are designed to provide better performance that is needed for such types of vehicles.
    It would not be ideal working with an inferior version of the spark plug in a modern vehicle that has a relatively higher demand level.

What Do The Spark Plugs Gap Do?

The space between the ground electrode and the side electrode is referred to as the gap of the plug; this needs to be at a specific length always.

It is the position of the spark plug that the spark ignites the air and fuel mixture and needs to be maintained for the optimal performance of the spark plug when in use.

For instance, when it is either too narrow or too wide, the engine might experience some complications that might make it unable to function well.

You may start realizing misfiring, fouling of the spark plug, wearing out of the spark plug, or even poor efficiency of the consumption of fuel from the vehicle’s engine.

When the gap is too narrow, the spark produced by the plug will be too weak to ignite the air and fuel mixture, and this might cause a case of incomplete combustion.

When it is too wide, the spark plug might misfire and have some complications when you are accelerating on the road.

As such, you need to maintain the measurement of the gap according to the manufacturer’s specs.

You can do this by gapping a spark plug before installation using the recommended ways of getting this done.


Now you know what do spark plugs do according to the information I provided above. You can also learn related questions below that people are curious about!

Q1. What Is Inside Of A Spark Plug?

The spark plug is comprised of a center electrode, an insulator, a metal casing, and a ground electrode.

Inside the plug is the center electrode that is laced horizontally along the length of the spark plug; its role is to conduct electricity from the ignition cable to the electrode gap.

The insulator is ceramic and covers the center electrode, leaving a part on the upper and lower end uncovered.

The metal casing appears as a hexagon-shaped shell that has threads along its surface.

The side electrode is designed as a short and thick wire that is made from nickel alloy, which is connected to both the metal shell and the center electrode.

The center electrode and the side electrode are separated by a gap that is approximately 0.05 inches, averagely, for the creation of the spark of the air and fuel mixture.

Q2. Are Spark Plugs Only Used For Starting?

No, the spark plugs are not only used for the starting of the vehicle, rather they have a number of uses in the vehicle engine. Unlike what many people think, the spark plug has a variety of uses.

For instance, they work as thermal regulators while they are in a position in the combustion chamber.

This they do to create a favorable temperature range for the optimal performance of the other parts in the combustion chamber.

Similarly, the spark plugs are also utilized when the car is moving on the road.

This is the case when you step on the gas pedal; you will realize that if the spark plug is not working well, the acceleration would not be as smooth as in a normal situation.

As such, you can realize that the spark plug is used on more than one occasion. In fact, it is used from the moment you ignite your car up until when you switch it off and park it!

Q3. How Often Does A Spark Plug Fire?

The rate of the firing of the spark plug depends on the type of engine that your vehicle is using.

For instance, for gasoline or any other type of engine that does not run on diesel, they fire one time for each combustion cycle.

This means that in the case of a four-cycle engine that is common for most cars around, they fire for every other crankshaft rotation.

For the two-cycle engines, the firing happens for every crankshaft rotation. This is the case for the engines of the chain saws, lawnmowers, or some motorcycles that were used way back.

In the case of the engines running on diesel, the spark plug works differently.

For these, a glow plug is used until the engine gets warm enough, and the air and fuel mixture gets ignited by itself. The compression of the engine helps with all this.

Q4. Which Is Better Iridium or Platinum Spark Plugs?

The iridium spark plugs are far much better than the platinum spark plugs.

What you should know is that both iridium and platinum are used on the tip of the spark plug’s electrode so that they improve their performance.

Either of these is much better for the optimal performance of the spark plug than the nickel alloy or any other type of metal that may be used.

Even though platinum spark plugs are a favorite for their longevity, iridium spark plugs beat them hands down because of more superior and energy-efficient features.

You can notice this by comparing every single property of either of the types of spark plugs.

Iridium, between the two, is a much better inclusion on the spark plug when it comes to optimizing its performance.

This is because it is relatively tougher than platinum and has a superior melting point than it.

This makes them last for longer than the platinum spark plugs as they are not that is easily vulnerable to wear and tear.

They also have a fine wire center electrode that conducts electrical energy better, and this improves the efficiency of the firing of the spark plug.

This is probably why they are costlier than the platinum spark plugs.


As seen in the discussion above, the spark plug is one item in the engine of the vehicle that plays a major role in determining its performance.

This is because it works all through from the moment the car is ignited to the time when you switch it off completely and park it.

This makes it quite a significant part of the engine of the vehicle.

This is probably why you need to have the spark plug in good condition so that the vehicle’s engine is at top performance most, if not all, the time you use it.


1. AutoAnything – https://www.autoanything.com/resources/what-do-spark-plugs-do/


Written by Kane Dan

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