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Can a spark plugs cause a car not to start

Can Spark Plugs Cause A Car Not To Start?

One of the most important minor components of your vehicle would be the spark plugs. The spark plugs are responsible for causing a spark that creates a minor fire and fires up the engine. For a car to work, the spark plugs need to be in optimal condition. Many have been asking if can spark plugs cause a car not to start.

One of the main symptoms of bad spark plugs would be when your vehicle cranks but doesn’t start. If the spark plugs are unable to cause the spark that causes your car to start, they would simply reduce the chances of your car ever starting or igniting to get the car running efficiently.

To help you better understand the role of spark plugs, we will look at some of the symptoms of spark plugs and what they do in your vehicle. You should know why and how spark plugs operate for you to know how they work. Once you know the symptoms, you will know to replace the spark plugs.

5 Common Symptoms Of Bad Spark Plugs

Fortunately, we now have the expertise to determine beforehand if the spark plugs are causing the issue or if your vehicle has any other issues related to starting the engine. Here we can look at some of the most common symptoms that would indicate your spark plugs are at fault or about to go:

1. Hard Starts

Car not starting
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Problem: Once you get behind the wheel of your car and turn the ignition, you might find that it cranks but does not start. This is typically a symptom of the spark plugs not creating a spark to ignite the fuel in the engine.

Solution: The solution would be to replace the spark plugs and ensure that they are in working order when you want to start the car. However, this could also be due to a flat battery. It is important to check and see if the car starts when replacing the spark plugs or you might have a dead battery.

2. Reduction In Overall Power

Car no power
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Problem: One of the main symptoms of dirty spark plugs would often be a reduction in the overall power of your vehicle. This could be due to misfires created by the dirty spark plugs or when only a few of them can work.

Solution: You should check the spark plugs to see if they are dirty or even flooded. If there has been any water damage to your engine, you could be dealing with flooded spark plugs. By cleaning or letting them dry efficiently, you should be able to get the spark plugs working.

3. Rough Idling

Man fixing car not idling
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Problem: Rough idling could be another symptom of dirty spark plugs. This is when the spark plugs only create a spark sporadically, which could reduce the efficacy of the idling of your vehicle. The spark plugs might once again be flooded, but they are often contaminated by fuel particles for the most part.

Solution: The same applies as in the previous point and you will need to make sure that your spark plugs are clean. One of the ways to do this is to remove each spark plug and wipe it down. You should leave it a few minutes to dry before replacing it. This should alleviate the problem and allow your vehicle to start once again.

4. Knocking Sound In The Engine

Loud car engine
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Problem: Another severe issue is often a bad knocking sound coming from the engine. The knocking sound would indicate that the spark plugs are not continuously igniting the fuel before it enters the combustion chamber. Your vehicle would often combine the factors of bad idling and a reduction of power.

Solution: This is often one of the telltale symptoms that you should consider replacing your spark plugs to have the fixed. You should focus on checking the plugs to make sure they are not dirty or impeded by oil or water. However, spark plugs are cheap to buy and very easy to replace without the assistance of a mechanic.


How Will My Car Act If The Spark Plugs Are Bad?

Before the car does not want to start, the first thing you would notice will be that the car would misfire continuously. The misfires would prevent the car from igniting and occasionally, you might have the ignition process take place. It could be frustrating to continually crank the car in an attempt to have it start.

How Do You Know If You Have A Starter Or Spark Plug Issue?

The starter motor is often another culprit, which could prevent your car from starting. The starter motor would stop the car from cranking and this could reduce the chances of the car eventually starting. The symptoms are similar and if you fix or replace the spark plugs and the car still doesn’t want to start, you could be dealing with a starter motor.

How Do You Know The Spark Plugs Failed?

Aside from simply replacing them and seeing if this fixes the issue, you might want to invest in a spark plug tester. The spark plug tester would check to see if it turns over when you turn the ignition. This would be a great indicator that it is time to replace the spark plugs.


An avid car enthusiast, I love spending time researching new cars and seeing how technology improves each year. With a passion for cars, I often find problems with certain vehicles and believe these should be addressed to ensure everyone can have a happy driving experience. I spend hours on the road each year and having driven numerous cars, I have encountered some basic and unique problems. I love sharing my knowledge and experience with you to help you prevent and even deal with some of these issues before they become fatal!!!

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