Why Do My Spark Plugs Keep Burning Out? [Here’s Why]

Spark plugs are an essential part of a gas-powered engine. They create the spark that ignites the air/fuel mixture. Meanwhile, the ignition coil creates the voltage required to spark the air/fuel mixture.

So, you might be asking, “why do my spark plugs keep burning out? Generally, engine overheating, wrong spark plug heat range, a loose spark plug, faulty fuel mixture that is too lean, or an ignition timing are all possible causes.

Continue reading to learn more about why spark plugs burn out.

Reasons Why Your Spark Plug Keeps Burning Out

Defective spark plugs can weaken your vehicle’s performance. Driving with damaged or fouled spark plugs can cause plenty of issues for your engine. You might notice the following.


Overheating the tip of a spark plug repeatedly might cause the plug to break early. Pre-ignition and a defective cooling system are some common reasons for overheating.

Pre-ignition can result from the spark plugs failing due to overheating in the combustion chamber.

The engine and spark plugs can overheat if the cooling system isn’t working properly. Overheating might cause the spark plug electrode to wear out more quickly.

Carbon Buildup

Sudden failure can also be caused by carbon accumulation on the tip. This can occur for various causes, including dirty injectors, a blocked air filter, etc.

Consider your machine as a fireplace or grill. When you burn wood, the smoke or carbon that coats the sidewalls is a by-product.

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Carbon accumulates in the cylinders and intake and exhaust valves for automobile engines.

Improper Ignition Timing

If the spark plug fires too early or too late during the compression stroke, damage to the engine might occur. Every cylinder is equipped with its plug fire. Turn off the first plug on the power stroke and the down plug on the power stroke to reduce emissions.

Normal system response times vary from 5 to 2 milliseconds. The spark counts as one line whenever it moves across the plug gap. There should be one difference between these two figures in most cases.

Your Spark Plugs Are Failing: Here’s Why

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Spark plugs can fail for various reasons, including inappropriate heat ranges, poor gapping, and chemical contamination.

A wrenched socket is required to secure every high-energy spark plug used in an industrial engine to a housing chamber.

The spark plug can release the enormous heat it creates via the cylinder head and align with its gas and electrical contacts.

For most cars, it should be replaced every 80,000 ~ 10,0000 miles. Malfunctioning spark plugs will result in noticeable problems with the engine. Some of the most common noticeable warnings of defective spark plugs in a car are listed below.

  • Engine misfire
  • Trouble starting
  • Increased fuel consumption
  • Rough idle
  • Struggle in acceleration

Frequently Asked Questions (FAQs)

Does a spark plug fire continuously?

Automobiles that run on biogas have shorter spacing than those on ordinary gasoline. The gap adjustment can be critical to the proper operating condition.

The plug will nearly always burn on each cycle, even if the gap is too small or weak to ignite the fuel-air mixture successfully.

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What color should spark plugs burn?

A light brown color indicates that the spark plug is at the proper temperature. It also means that the engine is in good working order. The side electrode of a regular spark plug will have brown or grayish-tan deposits.

How do you fix rich fuel mixtures?

You may solve this by installing an aftermarket air filter, replacing old spark plugs with newer ones with a larger heat range, and replacing ragged or broken ignition wires with fresher ones.

What is the typical spark plug burn time?

The duration of the ignition burn time should be roughly comparable. A response time of 1.0 to 2.0 milliseconds is considered normal. It may be acceptable depending on the engine and ignition system architecture.

How often does a spark plug fire?

Each spark plug fires once per two engine rotations due to how a conventional vehicle engine works.

Even when your car is idling at 800 rpm, the plugs must ignite 400 times each minute. Every other time, the piston goes down at the start of the cycle.

Pulling in fuel and air, then rises and compresses the mixture, then the mixture is ignited by the spark, producing tremendous heat.

The piston rises, forcing out the waste air-fuel, and the cycle is repeated at 3000 RPM. The power stroke occurs 1500 times per minute or 200 times per second in each cylinder.

How do I know if my fuel mixture is too rich?

Every time you start your car, many events occur. The pistons and crankshaft begin to move after the spark plugs ignite the engine. On the other hand, most cars run on either gasoline or fuel.

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When an automobile runs rich, the engine receives too much gasoline and not enough air. When your automobile runs rich, it will still start and move, but you’ll notice some trouble. This includes low gas mileage, slow acceleration, and a heavy gasoline odor.

What causes a spark plug to burn on an insulator?

Blistering on the insulator tip, melted electrodes or white deposits are indicators of a burned spark plug overheating.

In addition, engine overheating, inappropriate spark plug heat range, a loose spark plug, faulty ignition timing, or a fuel mixture that is too lean are all possible causes as well. When these happen, it’s time to replace the spark plug.

What causes spark plugs to run too hot?

A spark plug should work within a specific temperature range. When changing the spark plug, it’s advisable to take it when it’s cold. However, operating a plug too cold will cause damage.

It’s not easy to choose the right heat range spark plug. If you’re unsure, go with a plug on the colder side of the recommended heart range.

When the temperature is too low, you can increase the temperature by one digit. Below are some reasons why a spark plug runs too hot.

  • Tightening torque is insufficient
  • There is no gasket
  • Ignition timing is too advanced

Can a damaged spark plug be replaced on a weed eater?

These ignition systems generate a high voltage charge and go from the ignition module to the spark plug tip.

If the weed eater doesn’t make a spark, you’ll need to troubleshoot the complete ignition system to figure out what’s wrong.

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Like any other gas-powered tool, your weed wacker, also known as a string trimmer, relies on its spark plug for heat to ignite the gasoline in the ignition chamber.  

It’s normally near the handle, and its black wire connector, known as the boot, should be easy to see. A 5/8-, 3/4-, or 13/16-inch socket may be required to remove yours.

How do you check spark plugs without removing them?

A visual check may be sufficient to determine whether or not a spark plug is defective.

The center electrode will wear away with time, and it will no longer be able to perform its function. But what if it isn’t the case? What are the signs that the spark plug isn’t able to fire?

You can check if a spark is present at the coil pack or spark plug wire. It can conduct a spark by placing the screwdriver’s tip into the plug and bringing the shank to within 1/8th of an inch of the ground. During the test, don’t hang on to the screwdriver. You’re likely to be shocked if it isn’t isolated.

Spark Plugs Keep Burning Out

Your engine’s spark plugs must be clean, with no damage to the electrodes, in order for your car to work on all cylinders.

Certainly, spark plugs are unquestionably an important component of starting the car and must be attended to.

Maintaining the greatest possible condition of your spark plugs is the best approach to keeping an ignition coil from becoming a bad one.

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