What Are The Reasons For Bad Spark Plug Sound?

When I try to start my car it doesn’t start on the first try. I was in an urge to go to the office as I was late for 45 minutes. After a long trial, the car started. Soon I heard a knocking sound coming out of the engine. Also, my fuel level decreases soon than the normal scenario. I think it was a symptom of a bad spark plug sound.

The spark plug has to start up the fuel that makes an explosion which in turn generates power to the engine. There is no contact between those spark plugs. There must be a gap between them but they can generate electricity like an arc.  Otherwise, it results in a bad spark plug sound."Bad spark plug Sound" At some moment, when you ignite your car, it produces some unusual sound at the very beginning which irritates us. You feel hard to start up your car. This is due to having a bad spark. If you are also having a bad spark plug sound in your car, let’s check out the article to fix this problem.

What Are The Symptoms Of A Bad Spark Plug Sound?

Here are some of the reasons you need to figure out in your vehicle if you have a bad spark plug sound. They are

1. Engine Knocking

You may hear a distinct knocking sound while accelerating the car. This sound is created due to improper detonating spark plugs. This will ignite all the fuel present inside. Fuel and air vapor get fired and detonate instead of ignition. Thus bad spark plug causes engine knocking.

2. Hard Start

You need a perfect blending of fuel mixture and perfect combustion at the compressor while turning on the vehicle. Combustion is initiated by the ignition. Here the electrode at the end of the spark plug provides the ignition during the power stroke."Hard start"

There must be a small electrode gap for the better functioning of the spark plug. The spark plug fails to produce enough spark if the electrode gap increases. The electrode gap increases when the electrode is severely worn. The vehicle suffers from a hard start while experiencing a weak spark. This accounts for the symptoms of a bad spark plug sound.

3. Poor Fuel Economy

As mentioned earlier, a strong spark is necessary to run the vehicle more efficiently. In the absence of fuel, more gas will be used for the vehicle running. A worn electrode in the spark plug uses more gas to ignite the vehicle. Fuel economy will be decreased by 30% of normal fuel economy due to the bad spark plug."poor fuel Economy"

4. Misfire

The engine will start to misfire when the spark plug is completely worn. An appropriate ratio of air and fuel mixture is to be ignited in the engine during the power stroke. The engine will begin to shake at all speeds due to misfire. This lights up the check engine indicator. A bad spark plug triggers the misfire codes in the check engine light.

5. Poor Performing Engine

Decrease in engine performance and hesitation is noticeable during taking off when the spark plug worms completely. Rpm needle in the gauge began to bounce and the engine began to slightly shake. This usually indicates that all the spark plugs wear out at the same time.

6. Compression Leakage

This symptom can be found only through visual inspection. Look at the top of the insulator from the removed spark plugs. Look for the orange or the brown color. Then the spark plug is on its way out due to compression leakage.

Take a look at the tip of the electrode. If it is in white then your engine is running lean. If it is in black then your engine is running in a rich condition.

What Are The Reasons For The Bad Spark Plug Sound?

Three things can damage the spark plug. They are

1. Rich Fuel Mixture

Gray or matte black appears over the spark plug. It has disturbed evenly over the spark plug electrode and porcelain. Too much fuel in the cylinder makes the spark plug grey. Carbon which is released as the result of combustion gets onto the parts of plugs and sticks. The Two ways to finds whether the engine is using a rich fuel mixture or not are

  • Look into the short-term and long-term fuel numbers
  • Look at the state of injectors whether it is a clogged injector or a stuck injector.

Using this way we could assume that they have damaged the spark plug.

2. Engine Oil Leak

Another cause that can damage a spark plug is an Engine oil leak. Engine oil deposits on the spark plug will have a black finish or the shiny black finish. You can differentiate oil leaks from carbon deposits by the point that oil leaks will be inconsistent and accumulate in some of the colder areas of the spark plug.

This oil leak on the spark can also be caused by two other reasons they are

  • Due to the positive crankcase ventilation system
  • Due to the things which allow crankcase vapors and oil droplets into the combustion chamber."oil leak"

Also, take a look at these side issues while replacing the spark plugs.

3. Coolant Leaking

Coolant can cause damage to the spark plug. A leaking head gasket or the intake manifold gasket in the vehicle allows the coolant to get into the combustion chamber. Ii sticks to the spark plug. It deposits a grey-ashy look in color.

Some issues can contaminate the spark plug. Resolve these issues before replacing the bad spark plug sound

How To Replace My Bad Spark Plug?

On average, a spark plug has to be replaced every 30,000 to 60,000 miles. It can vary depending upon the manufacturers and the build quality. For better precision go through the user manual."Replace my spark plug"

Steps to be followed while replacing the bad spark plug are

  • Spot the spark plug located in the vehicle.
  • Pull out the spark plug wires without damaging them.
  • Using the spark plug socket pull them out.
  • Go for a visual inspection whether it has been damaged or not.
  • Go for the new spark plug as same as the old one.
  • Check whether the electrode gap is perfect or not.
  • An appropriate electrode gap is mentioned in the user’s manual.
  • Use dielectric grease over the spark plug, spark plug wires, and the caps as an insulator.
  • Replace the spark plug with the help of a spark plug socket.
  • Follow these for the remaining number of spark plug

Now you have successfully installed the brand new spark plug without the help of auto-mechanics.

Which Engine Has Spark Plugs To Ignite?

Generally, spark plugs are present in fuel engine vehicles. Fuel engines are interns known as spark engines. Spark is nothing but a little electrical ignition to start up the car. In petrol engines, it helps to start up the fuel mixture. But in the case of a diesel engine, there is no compulsion to have those spark plugs as it can start up without this.

What Happens If I Use A Bad Spark Plug For A Long Time?

Having a good spark plug less the workload of your engine to start up the car. But if you have a bad spark plug it leads the engine to put enormous energy. If the condition stays long or if you take a long time to replace the spark plug, the engine will face so many issues with it. It starts to lose its capacity soon. If the engine alone generates enormous power for a long time it may lead the engine even to completely shut down.


Thus engine knocking, starting trouble in vehicles, engine misfires, and consumption of higher volume of fuel are the potential symptoms of the bad spark plug. You can replace the damaged spark plug with your newly purchased spark plug by yourself or with the help of an auto mechanic.

"bad spark plug"

A good start-up always leads to a good journey. Likewise having a good spark plug ignites your engine smoothly. If you’re hearing a bad spark plug sound then take immediate action to save the life of your engine. If measures shouldn’t be taken, let it dry your engine soon. Hope you have understood what are the symptoms of a bad spark plug sound? and how to rectify it?. If any queries kindly comment below.

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