What Causes Spark Plugs To Go Bad Fast? (8 Causes)

Spark plugs create the spark needed to ignite the air and fuel mixture inside the engine. This allows you to start the car and keep it running. They are a crucial component in the combustion process and must stay operational. So, what causes spark plugs to go bad fast?

There are several reasons why spark plugs wear out or burn out fast. This is especially if they are new. In this post, you’ll learn some of the causes behind it and the symptoms you should watch out for.

Here’s what causes spark plugs to go bad fast

1.     Leaking oil

The most common cause behind spark plugs that wear out fast is oil that leaks into the combustion chamber. This happens a lot in older vehicles that burn too much oil.

The steady flow of oil causes the tip of the spark plugs to get dirty and oily. This results in oil buildup which shortens the life of the plugs and causes them to fail eventually.

2.     Carbon buildup

When your vehicle continuously burns a rich mix of fuel and air, it produces carbon and soot that deposits on some of the engine parts.

The carbon buildup finds its way to the spark plugs and creates a coating on the electrodes that reduces the lifespan of the plugs. It also causes them to turn black.

In addition to burning a rich mix of fuel and air, other reasons for carbon buildup include dirty fuel injectors, a clogged air filter, a bad distributor case, and driving excessively at slow speeds.

3.     Overheating

Continuous overheating of the spark plug electrodes causes them to wear out prematurely. Some of the causes behind this include pre-ignition and wrong ignition timing.

It leads to heat buildup in the combustion chamber. If the cooling system does not respond appropriately, it will cause some of the engine components to burn out fast, including the plugs.

4.     Improper spark plug gap

A well-functioning spark plug has a gap at the tip between the center and the electrode. This gap must be precisely calibrated to ensure arcing occurs at the right voltage.

This ignites the fuel and air mixture to make the engine run. If the gap isn’t right, it causes extra stress on the tip and causes the metal parts to wear out and erode faster.

The specific gap measurement is done for the type of engine in question during installation. If any of the spark plugs is slightly off, it will go bad fast.

5.     Poor fuel quality

Contaminated fuel may cause unwanted debris to go past the fuel filter and get into the engine through the intake manifold.

Leaded fuel is also known to introduce lead inside the engine which ends up depositing on the spark plugs and causing premature wear.

This and other contaminants can cause electrical shorts that will ruin the spark plugs and affect the performance of the engine.

6.     Electrical problems

Sparks also go bad fast due to loose wire connections or low-quality plugs. This causes problems in how voltage is sent to the spark plugs.

Ensure that all the electrical connections are perfect and that there are no corroded or damaged connectors when installing your spark plugs. Also, use only high-quality plugs that will last long.

7.     Clogged fuel filter

A fuel filter provides protection against rust particles, dirt, debris, and other contaminants. When it gets clogged, it can allow the contaminants to find their way to the engine.

This can affect the performance of your spark plugs. It’s important to carry out your scheduled maintenance and replace the fuel filter when needed.

8.     Spark plug maintenance

Auto professionals recommend changing your spark plugs after every 30,000 miles or after every 3 years. But, it’s good to note that the lifespan depends on the driving conditions the plugs are subjected to.

If you notice any signs of wear or experience performance issues that indicate you have a bad spark plug, do a proper diagnosis.

Also, use high-quality fuel and good synthetic engine oil. You will be able to prevent new spark plugs from suddenly going bad.

What happens when spark plugs go bad fast?

Below are the most common signs of bad spark plugs:

1.     Poor fuel economy

Bad spark plugs can fire erratically causing wastage of fuel and increased emissions. This is mostly caused by aging spark plugs.

The space between the two electric contacts expands over time causing firing issues. This results in inefficient combustion, which leads to more trips to the gas station.

2.     Engine misfire

A misfire occurs when one or more engine cylinders fails to produce the power needed. It’s a common sign when one of the spark plugs goes bad.

It may be characterized by violent shaking, sputtering noises, and a sudden loss of engine power. If the misfiring goes on for a long time, it will cause more damage to the engine.

3.     Rough idling

Rough idling is normally characterized by fluctuating engine RPMs. Look out for any signs of pinging, knocking, or rattling.

These could indicate that you have bad spark plugs that are preventing the engine from running smoothly at idle.

4.     Acceleration problems

Spark plugs that delay firing can cause a slow response when you step on the gas. This causes acceleration issues that prevent your car from increasing speed.

However, it’s good to note that this can also be caused by other faults such as dirty fuel injectors, a failing fuel pump, and bad oxygen sensors.

Take your vehicle for a proper diagnosis when you start to see acceleration problems.

5.     Hard starts

Spark plugs must deliver the initial spark to start the engine. This is very important, especially in cold weather.

If the plugs are worn-out, dirty, or damaged, they may cause a jerk as the vehicle struggles to start. If this goes on long enough, it can result in a dead car battery and damage the engine.

Frequently Asked Questions

How quick can a spark plug go bad?

Most car professionals recommend replacing your spark plugs after every 30,000 miles (45,000 km). However, it’s good to note that spark plugs can serve up to 100,000 miles without going bad.

Those made of iridium and platinum are known to last longer than copper spark plugs. The lifespan also depends on the condition the plugs are subjected to inside the engine.

Do spark plugs go bad after sitting?

Spark plugs do not typically go bad after sitting for a long time. This is because they are designed to last for years without going bad.

The only thing that causes them to wear out is overheating and other extreme conditions when in use. Expect your spark plugs to last at least 30,000 miles before needing to be replaced.

What kills a spark plug?

The most common spark plug destroyer is overheating. Once the temperatures rise above 8500C or 15000F, the ceramic material on the center electrode starts to blister and causes the electrodes to melt. This will affect how the engine fires and lead to severe engine damage in most cases.

What happens when you over tighten spark plugs?

It weakens and damages the spark plug threads. This can cause the plugs to blow out and take the cylinder head threads with them.

It’s important to properly torque the spark plugs and to avoid overtightening them. Ideally, anything that needs to be threaded in your car should not be overly tight.

Should I replace ignition coils with spark plugs?

You can replace the ignition coils as well if the spark plugs caused excessive load on them.

It helps to improve the vehicle’s performance and ensure that the firing of the air and fuel mixture is right. It’s common for mechanics to replace ignition coils alongside the spark plugs.

What visual signs would you find on a spark plug that needs to be replaced?

A good spark plug should be light grey or brown at the firing end. This indicates that the electrodes are clean and working well.

Any signs of charring, black carbon buildup, white deposits, oil, or soot indicate that the spark plugs are contaminated and may interfere with the ignition system.

On That Note

Once you know the signs and symptoms to watch out for and the causes behind bad spark plugs, it becomes easier to figure out what to do when you need to change the spark plugs. Since other problems can cause some of the performance issues discussed, it’s important to do a proper diagnosis on the vehicle.