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What happens when spark plugs go bad? Tips to Prevent Spark Plugs from Going Bad

What Happens When Spark Plugs Go Bad

Is your car’s engine not performing well and showing unusual issues? Then your first duty will be to check the spark plug because most of engine issues arise from a bad spark plug. We are about to elaborately say, what are the possible outcomes of bad spark plugs.

What Happens When Spark Plugs Go Bad

You will also know about the reasons and precautions regarding spark plugs going bad. Hope your vehicle is going to benefit from it! 



1. Lack of maintenance:

 When one does car servicing, most of the time, the spark plugs are overlooked! But they require maintenance to be the most crucial component there. As a result, oil from the engine starts to build up in the plugs’ combustion chambers.

Over time, the oil congests the chambers resulting in improper functioning. Hence, if the chambers are cleaned once a while, then the spark plugs won’t go bad.

2. Overheating:

 The spark plug can get overheated due to lots of reasons. One of the main reasons is when your engine gets overheated and the cooling system malfunctions, which passes on the heat to the spark plugs.

Especially, the tip of the spark plug gets affected first due to overheating and causes premature wearing.

3. Carbon build-up:

 Like oil, you need to see if your spark plugs are getting carbon build-up or not. The longtime build-up from carbon deposits makes the spark plugs look black and corroded.

Carbon can damage the spark plugs through dirty fuel injectors, clogged air filter, or even cracked distributor cases. 

4. Improper placement: 

Improper placement of the spark plugs, such as gaps, causes the insulator tip to stress, making the plugs erode out faster. If any one’s gapping is misplaced, then slowly, the entire spark plug set suffers.

What Happens If You Drive With Bad Spark Plugs?

First, you’re likely to have trouble starting. You could go through several attempts at turning over the engine, so make sure to check your spark plugs regularly. 

Second, you might notice that your car is low on power or its fuel economy has decreased drastically. 

Lastly, you may hear a loud knocking coming from your engine, as the pistons will work harder due to the lack of spark.

What Does Bad Spark Plugs Sound Like?

Engine knocking, or detonation is a sound that can be described as thumping, banging, or popping. It is normally caused by improper fuel combustion inside the engine and is an extremely common indicator of an issue with the car’s spark plugs.

What Happens If Spark Plugs Are Not Changed?

Spark plugs will eventually wear out, becoming fouled with carbon deposits and dirt. This leads to the spark plug gaps becoming too wide, meaning that the spark can no longer bridge the gap and ignite the air/fuel mixture. Over time, the spark plug firing end will become hotter, which can eventually lead to failure. 

How to start a car with bad spark plugs

So how do you start a car with bad spark plugs? Here’s what you need to do:

  1. Start by locating the spark plugs in your car. Most newer cars will have them near the engine’s top, while older ones will have them near the bottom.
  2. Disconnect the spark plug wires from the spark plugs. Make sure you remember which spark plug wire goes to which spark plug.
  3. Inspect each of the spark plugs. If they are completely worn out or worn to the point where it is impossible to clean them, it is time to replace them. Look for visible damage to the electrode or the surrounding metal. If the plug is visibly damaged, replace it.
  4. Install the new spark plugs. First, install the spark plugs into the engine, making sure not to overtighten them. T
  5. Start the car to make sure the spark plugs are working properly. If your car still isn’t starting, you may need to check the other components of the ignition system, such as the spark plug wires, distributor cap, and spark plug coils.

Do new spark plugs make a difference?

The answer is a resounding yes! Spark plugs are a critical component of any vehicle’s performance. They are responsible for providing the correct spark that ignites the air-fuel mixture in the combustion chamber and powers the engine. 

Why do spark plugs go bad fast?

The most common reason spark plugs go bad quickly is because of carbon deposits. When the fuel mixes with air, it undergoes combustion. This process creates thousands of tiny carbon particles, which can build up in and around the spark plug. Over time, these deposits can thickly cover the spark plug, which prevents the spark from lighting the fuel.

How do you check spark plugs?

Step 1: Examine the Spark Plugs for Damage

Look closely at the spark plug to see if any dirt, oil, or corrosion is on any of the threads. Also, check the electrodes, ceramic insulator, and any other spark plug parts for signs of damage or wear.

Step 2: Check the Gap Between the Electrodes

Once you’ve given the spark plugs a thorough visual inspection, use a spark plug gap tool to check the gap between the electrodes.

Step 3: Clean or Replace the Spark Plugs

If you see any dirt or corrosion on the spark plugs, it’s best to clean them with a spark plug cleaner. If the electrodes or other parts of the spark plugs show signs of wear or damage, you should replace the plugs with new ones.

Step 4: Tighten the Spark Plugs

Once the spark plugs are clean (or replaced), use the spark plug gap tool to set the gap back to the correct setting. Then tighten the spark plugs with a good torque wrench.



1. Hampered acceleration:

 Acceleration will get rough or slowed down due to a bad spark plug. The spark plugs’ air-fuel combustion chambers won’t ignite as much as they should creating a smooth and steady acceleration.

2. Engine idling:

 It’s the most common problem everyone faces that occurs due to bad spark plug misfiring. The fuel does not burn enough fuel because of worn-out plugs.

Hence, your car starts rough idling. In some cases, the car also starts to sound like a tractor.

3. Fast fuel consumption:

Bad Spark plugs handle fuel inefficiently. Hence, you will have to visit the gas station often, as more gas gets consumed in less time.

If your car is old, you may not find fast-gas consumption relatable with bad spark plugs. Instead, you would think the engine got faulty over time.  Still, do check the spark plugs too.

4. Engine light showing misfire:

 Often, engine control displays misfiring, which occurs for bad spark plugs. Therefore, the trouble code on display brightens up. Then you know that something is wrong with the spark plugs.



Check them:

 Even if you do nothing for them, you should check them at least after every 24 hours of use. If any issue arises, you will get to beforehand rather than being late to prevent the mishaps.

Clean them:

 As a part of maintenance, clean the spark plugs once a while. Routine Cleaning will elongate their shelf life and prevent them from getting any buildup. Make sure you know the cleaning process and do not use harsh cleaners.

Hire a professional for any replacement: 

If you think of saving labor cost by replacing the spark plugs yourself with no prior knowledge, you are thinking wrong. Not placing the spark plugs the right way and position troubleshoot their performance to a great extent.

Spark Plug Location:

Spark plugs are placed under the ignition coil of the engine’s cylinder. Mostly, they are under the engine’s top cover. However, in some vehicles, the plugs are situated beside the cylinder head that makes the placement a bit harder.



Why is Spark Plug important in a vehicle?

The engine makes your vehicle run, and spark plugs make that engine run! So, now you know why it is such an essential component in a vehicle. These plugs are the engine’s power producers.

Does every vehicle contain spark plugs?

Any vehicle that runs with an engine contains a spark plug! Without them, the engine won’t produce fuel by converting chemical energy.


Now that you the results of spark plug going bad and its importance for your vehicle keep them safe! If you ever feel the need to change the spark plugs, then do that without any hesitation, as their cost is insignificant compared to the entire vehicle.

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