6 Bad spark plug symptoms and signs

Spark plugs are an important component of a car with a gasoline engine. The function of the spark plug is to produce a spark in the combustion chamber so that the mixture of fuel (gasoline) and air that has been compressed can be detonated and produce engine power. Without sparks from the spark plugs, the engine cannot start and cannot generate power to turn the wheels.

Like other car engine components with service life, so do spark plugs. It also has a service life, and we must replace the spark plug when the time has passed. We can replace the spark plugs based on the distance traveled or the length of time used.

For more details, please read the article When To Change Spark Plugs In A Car? Here's The Explanation, which has been posted previously.

In addition, we can also find out bad spark plug symptoms based on the conditions that occur in the engine. Well, the following article will tell you the signs of bad spark plug symptoms that we can know. Check out the full information below.

1. The engine is difficult to run

The first bad spark plug symptom is the engine is difficult to run. When the spark plug goes bad, the engine is easy to start, but it does not run even though we did start the engine many times. If the condition is like this, the number of damaged spark plugs is usually more than one.

If only one spark plug is damaged, the engine is usually still easy to start, but with a longer starter duration than when the spark plug was still good. Yes, spark plugs have an important role in burning a mixture of fuel and compressed air to produce engine power. Without a spark plug that works properly, the engine will be difficult to run and generate power.

2. Engine vibrates violently at idle and low rpm

The second bad spark plug symptom is when the engine feels vibrates at idle and low rpm conditions. Partially damaged car spark plugs (such as one or two damaged spark plugs) are often the cause of the engine vibrating and unsteady at low rpm. Mostly, the engine vibrates at idle, and this low rpm can also affect engine power. Usually, the engine becomes powerless and less responsive.

Damaged and dead spark plugs will make one or part of the engine cylinders not produce power. This condition makes the engine work imperfectly and makes the engine spin unbalanced, causing vibrations at both idle and low rpm. When the rpm is high, the engine's symptoms of limpness and vibration will usually disappear by themselves.

3. Exhaust smoke stings and smells bad

In addition to the engine vibrating and being difficult to start, the next sign of bad spark plugs is when the exhaust smoke feels stings and has a pungent odor. Yes, when the spark plug is partially dead or damaged, the exhaust fumes that come out will sting in the eyes, besides the pungent smell of fuel that is not completely burned will also be felt.

This condition indicates that one or part of the engine cylinder does not burn the compressed fuel mixture. As a result, the remaining fuel comes together through the exhaust gases from other cylinders. This condition can also cause the engine to waste more fuel, thereby reducing gas mileage.

4. The spark plug full of fouled carbon

The next sign of a bad spark plug is when the color of the spark plug head turns black and looks like it's wet with oil (fouled carbon). The color of the spark plug head, black soot and wet with oil, indicates that the spark has not occurred in the spark plug, so a spark plug replacement is required.

However, this condition does not indicate certainty that we must replace the spark plug. But from many experiences, the condition of this spark plug is no longer suitable for use.

Therefore, a tool called a spark plug tester is needed to determine whether the spark plug can still be used or must be replaced.

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5. The spark plugs gap is wider

Another bad spark plug symptom that needs to be replaced is when the spark gap is too wide. Due to the spark plug gap being too wide, replacement spark plugs are often done on iridium spark plugs. The reason is that we cannot adjust the spark plug gap on the iridium spark plug. It's different from traditional spark plugs. If the spark gap is too wide, it can still be adjusted back to the factory standard size.

6. The spark plugs can no longer produce a spark

The last sign of bad spark plugs symptom is when the spark plugs can no longer produce sparks. Generating sparks at this spark plug's head is the spark plug's main function. Without it, the engine will not be able to start.

To find out if the spark plugs can no longer produce sparks, we can use a spark plug tester or see directly when the engine is started. If there is no spark at the head of the spark plug, we must replace the spark plug with a new one.

That's the article about bad spark plugs symptoms that need to be replaced that we can convey this time. Hopefully, this article can be useful.