Will Bad Spark Plugs Cause Check Engine Light?

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Will Bad Spark Plugs Cause Check Engine Light

The check engine light can be a significant worry for drivers when it suddenly illuminates your dashboard. It can signify numerous issues and can leave you driving uncertainly. One of the possible reasons behind your check engine light coming on could be bad spark plugs. They can cause problems with your vehicle’s ignition system and can make your car drive poorly.

In this blog, we will be discussing whether bad spark plugs can cause the check engine light to come on, the symptoms of bad spark plugs, how to reset the check engine light after changing spark plugs, and the relationship between spark plugs and check engine light.

1: What are Spark Plugs and How Do They Work?

Spark plugs are small devices that generate an electrical spark to ignite the fuel and air mixture in your engine’s combustion chamber. They sit on top of your engine’s cylinders and are connected to the ignition system. The spark plugs’ performance directly impacts your engine’s power, smoothness, and fuel efficiency.

2: Can Bad Spark Plugs Cause The Check Engine Light?

Bad Spark Plugs

The spark plugs play an essential role in your vehicle’s engine ignition system as they ignite the fuel/air mixture that supplies power to your engine. A malfunctioning spark plug can keep your engine from starting or running as it should. So, can bad spark plugs cause your check engine light to turn on? The answer is yes.

The electronic control unit (ECU) is responsible for regulating the engine’s performance, including the ignition system. If the spark plugs are weak or faulty, the ECU will detect a problem and may cause the check engine light to illuminate on your dashboard.

1: What are the symptoms of bad spark plugs?

Some common symptoms of bad spark plugs are given below:

1.1: Decreased fuel efficiency:

As spark plugs begin to wear out, they can cause a decrease in fuel efficiency, leading to reduced mileage. This happens when the spark plugs fail to ignite the fuel-air mixture completely, and the engine needs more fuel to obtain the same level of power and performance.

If you notice a decrease in your car’s fuel economy, or if you find yourself frequently refilling the gas tank, it may be time to replace your spark plugs.

1.2: Rough Engine Start:

Bad spark plugs can cause your engine to start roughly or a noticeable delay between attempting to start the car and the engine starting. As the spark plugs age, they may produce a weaker spark, and the engine may take longer to start, causing a jerking or shuddering sensation as it struggles to turn over. If your car seems to hesitate or takes a while to start, it’s time to get your spark plugs checked.

1.3: Misfiring engine:

A misfiring engine is a clear sign of bad spark plugs. Misfiring occurs when the spark plugs fail to ignite the fuel-air mixture properly, causing the engine to experience a momentary loss of power. You might notice a rough or jerky sensation when driving, especially when accelerating.

It can be especially problematic while driving at high speeds, causing the engine to stutter and shaking the car. A mechanic can replace your spark plugs to fix this issue.

1.4: Engine Warning Light:

If your car’s dashboard warning light – like the check engine light – is turning on, it can indicate a problem with the spark plugs. The engine warning light commonly triggers when the ignition system fails to operate correctly, causing bad spark plug symptoms in the engine.

If the light is flashing or continuously flickering or the car running rough or misfiring continuously, it’s essential to take your car to the mechanic as soon as possible to avoid further damage.

1.5: Slow acceleration:

If your car’s acceleration seems sluggish or ‘bogged down’ when you press down on the gas pedal, it could indicate bad spark plugs. It means that the spark plugs are failing to ignite the fuel-air mixture quickly enough, causing the engine to be slow to respond. In this case, a simple tune-up can do the trick, improving your car’s acceleration significantly.

2: How to Reset Check Engine Light After Changing Spark Plugs?

List of steps to follow for resetting the check engine light after replacing the spark plugs is:

Step 1: Disconnect the Battery:

The first step in resetting your check engine light is to disconnect the battery. Locate your car’s battery and use a wrench to disconnect the negative cable. Leave the battery disconnected for at least 15 minutes to allow all the capacitors and other electronic components in the car to discharge. This will ensure that the computer and all the sensors that were detecting the spark plug change are reset.

Step 2: Plug in the OBDII Scanner:

Once the battery has been disconnected, plug in the OBDII scanner to the car’s diagnostic port. You can locate the diagnostic port under the dashboard, near the steering wheel. Once you’ve plugged in the OBDII scanner, turn on the ignition of the car but do not start it. The scanner will read the codes appearing in the car’s computer.


3: How to Check and Replace Spark Plugs?

If you suspect that your spark plugs are causing your check engine light to turn on, you can take your car to a mechanic to have them inspected. They will perform a diagnostic test with a scan tool to retrieve the error codes stored in your car’s computer.

These codes will provide valuable insight into the cause of your car’s poor performance. If you need to replace your spark plugs, the mechanic will remove them from their sockets and install new ones. Alternatively, you can also replace them yourself if you have some experience working on cars.

4: How to Maintain Your Spark Plugs Properly?

To avoid spark plug-related issues, you should make sure to perform regular maintenance on your car’s engine. Spark plugs typically last between 30,000 and 100,000 miles, depending on their type, quality, and driving conditions.

You should follow your car’s manufacturer’s recommendations for replacing the spark plugs and check them periodically for signs of wear or fouling. Additionally, you should keep your car’s air filters and fuel filters clean to ensure that the engine receives the right amount of air and fuel to operate efficiently.

5: Why is my car misfiring after changing spark plugs?

Have you ever changed your car’s spark plugs only to find out that it’s suddenly running rough or misfiring? You may be wondering why this is happening despite replacing the spark plugs with high-quality ones. Misfires can occur for a variety of reasons, and today we’ll discuss some of the reasons why your car may be misfiring after changing spark plugs.

1: Loose or damaged spark plug wires:

Mechanics often detach and re-attach the wires connecting spark plugs to the ignition coil or distributor cap when performing replacements. If these wires are not screwed on tightly enough or damaged in the process, they can cause misfires. Check all the spark plug wires and make sure they’re secure and not frayed or cracked.

2: Faulty ignition coil:

A faulty ignition coil could be one of the culprits behind your misfire. It’s responsible for producing electrical power for the spark plugs to ignite the air/fuel mixture in the combustion chamber. If it’s not performing correctly, it can lead to a misfire or rough-running engine. If you suspect your ignition coil is faulty, you can test it using a multimeter, or consult a mechanic to diagnose the issue.

3: Incorrect spark plug gap:

Every car has a specific gap requirement for its spark plugs, and if this gap is too small, it can cause a misfire. Use a spark plug gap gauge to ensure the spark plug gap is set correctly, and adjust it carefully to the manufacturer’s specifications.

4: Dirty air filter:

A dirty air filter can restrict airflow into the engine, leading to incomplete combustion and misfires. It can also cause a rich fuel mixture, which can further clog up the spark plugs with black soot or cause fouling. Check your air filter and consider replacing it if it’s dirty or clogged.

5: Failed fuel injector:

Fuel injectors are responsible for delivering fuel to the combustion chamber, and if one or more is faulty, it can cause misfires. A fuel injector that’s clogged or stuck open can lead to constant or intermittent misfires and damage the spark plugs. If you suspect your fuel injectors are faulty, consider having a professional test and clean them.

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6: Conclusion:

In conclusion, bad spark plugs can be the reason behind your check engine light turning on. It is essential to identify the symptoms of bad spark plugs, and even after replacing them, resetting the check engine light is necessary. Always check the spark plug code and have it inspected immediately. Taking care of your vehicle’s spark plugs is crucial for your car’s performance and your safety. In case you are not confident about the DIY procedures, consult a professional mechanic.

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