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The proper functioning of a vehicle’s engine greatly relies on spark plugs. They are responsible for generating the spark that ignites the fuel and air mixture in the combustion chamber, which ultimately powers your car or truck. With time, these tiny parts may wear out or get damaged, resulting in an irregular gap between them. This can cause misfires, decreased performance, and even damage your engine. In this article, we will guide you through everything you need to know about How to Close the Gap on Spark Plugs – from identifying when it needs adjustment to step-by-step instructions for doing it yourself.

How to Close the Gap on Spark Plugs

How to Close the Gap on Spark Plugs

The gap on spark plugs refers to the distance between the center and ground electrodes at the tip. This gap is critical in ensuring proper ignition timing and combustion within an engine cylinder. Closing this gap can improve engine performance by increasing power output and fuel efficiency while reducing emissions. Car owners often face the gap between spark plugs becoming too wide or narrow. If this happens, it can cause poor fuel efficiency or lead to the engine not starting. So what should you do if you need to close the gap on your spark plugs? Here are some steps that you can follow.

Select a gap gauge or a feeler gauge.

When selecting a gap gauge or a feeler gauge, there are definite things to consider. The first thing you need to consider is the gap’s size. The gap size will dictate which gauge type you should use, as each gauge has different thicknesses and ranges. For example, a thin feeler gauge would work with small gaps. But a thicker gauge would work better when dealing with more significant gaps.

The next thing to consider is the material used to make a gauge. Different materials are available for gauges, such as plastic, brass, and steel. Each material has advantages and disadvantages, so choosing one that will suit your needs is essential. Plastic gauges are inexpensive but not very durable and tend to wear quickly.

Wash the spark plug

Washing your spark plug can help to keep your engine running smoothly. Carbon deposits and other debris can build up on the spark plug’s surface, leading to poor performance and engine damage. By washing your spark plug regularly, you can remove these deposits and ensure it works as efficiently as possible.

To wash a spark plug, first, remove it from the engine using a wrench or socket set. Use a wire brush or abrasive pad to gently scrub away any debris that has built up on the surface of the electrode. Be careful not to bend or damage the electrode while cleaning it, as this could cause problems when you try to reinstall it. Once you have cleaned the electrode thoroughly, rinse it off with water and allow it to dry completely before reinstalling it in your engine.

Gap measurement

To ensure the smooth and efficient functioning of your vehicle, it is essential to maintain the spark plug of your engine correctly. Measuring the gap between the center and ground electrodes on a spark plug is essential to maintenance. Your owner’s manual should provide the correct gap measurement range for your specific vehicle.

To determine if your spark arrestor falls within this range, run the spark plug inspection tool through each arrestor in the circuit. This process is relatively simple and involves removing each spark plug from its cylinder head and using a feeler gauge to measure its gap distance. If plugs fall outside the recommended range, it may be time for a replacement or further investigation into potential engine issues. Regularly checking and maintaining proper gap measurements in your vehicle’s spark plugs can help avoid potential performance problems such as misfires or decreased fuel efficiency.


Checking and adjusting the spark plugs is considered one of the most crucial tasks in car maintenance. Preventing spark plug wires from arcing is another essential aspect of car maintenance that complements checking and adjusting spark plugs. Here are a few steps to adjust the spark plugs in your vehicle.

Remove the spark plug wires with a twisting motion so you don’t damage them. Use a socket wrench to unscrew each spark plug from its hole one at a time. Check the condition of each one and clean them with a wire brush or replace them if necessary. Set the gap on each plug using a feeler gauge or checking your car’s manufacturer specifications. Then, screw each new or cleaned spark plug back into place and reattach the wires firmly but gently.

Examine the process

If you’re experiencing engine issues, the spark plug gap may be a culprit. The gap between a spark plug’s centre and ground electrodes is critical to proper combustion in an engine. It can affect performance and fuel economy even if it’s slightly off. That’s why it’s essential to ensure that the gap is error-free.

To examine the process, remove each spark plug from your engine and inspect them for wear or damage. Next, measure the gap using a feeler gauge. If it isn’t within specifications, adjust it accordingly using pliers or specialized tools designed for this purpose. After adjusting, recheck the gap to ensure accuracy before reinstalling the plugs into your engine. It’s important to note that getting the proper spark plug gap requires patience and attention to detail.


Closing the gap on spark plugs is a quick and easy maintenance task that can improve your vehicle’s performance and fuel efficiency. With the right tools and knowledge, you can confidently adjust the gap to ensure proper ignition and prevent misfires. Regularly checking and adjusting your spark plug gap will also prolong the lifespan of your vehicle’s engine. Consult your owner’s manual for recommended gap measurements, and be cautious when working with electrical components. Take care of your car’s spark plugs, and it will take care of you on the road. So, don’t hesitate to close that gap today!

Frequently Asked Question

How Can You Create The Difference Between A Gap And A Spark Plug Gap?

Understand what the optimal gap size is for your specific engine. This information can usually be found in your vehicle’s owner manual or by consulting with a mechanic. Once you know the recommended gap size, you must use a feeler gauge to measure and adjust the existing gap if needed. To adjust the spark plug gap, gently bend the ground electrode towards or away from the center electrode using pliers until it matches the recommended size. Ensure not to touch either electrode with your fingers, as oil residue can interfere with the electrical flow.

Why Does The Gap On The Spark Plug Matter?

A correctly set spark plug gap can improve fuel efficiency, reduce emissions, and enhance engine performance. This affects the intensity of the spark generated when electricity flows through it. If the gap is too small or too large, there will be insufficient voltage to ignite the fuel-air mixture efficiently, leading to poor combustion and decreased power output from your engine.