How to Splice Spark Plug Wire – 5 Easy Steps

Knowing how to splice spark plug wire is a crucial skill that may save you time, money, and heartache whether you’re a seasoned technician or a DIY enthusiast. Repairing or replacing faulty spark plug wires may keep your engine running smoothly and effectively, whether you’re restoring historical autos or maintaining your everyday vehicle. 

In this post, we’ll walk you through the step-by-step procedure of splicing spark plug wires like a pro, ensuring that your ignition system is in top shape for peak performance. So gather your tools and prepare to master this fundamental skill that every vehicle enthusiast should know.

How to Splice Spark Plug Wire – Step by Step

Step 1: Detach and Assess the Spark Plug

This entails disconnecting the spark plug wire after stopping the engine and letting it cool. After the cable has been disconnected, look for any evidence of wear or damage. The functionality of the wire can be greatly impacted by fraying or spark plug cracks, so it is imperative to make sure there are none throughout its length.

Step 2: Remove Damaged Open Barrel Terminal

The broken open barrel terminal must be removed with dexterity and accuracy. Using wire cutters, start by gently removing any insulation that is close to the terminal. Next, use pliers to carefully crimp a small section of the termination to release its hold on the wire.

Release the grip and remove the terminal by sliding it off the wire, then dispose of it. Making sure that there are no traces of the old terminal remaining on the cable is essential.

Step 3: Strip the Wire

After cutting the wire to the required length, carefully remove the insulation from the end of the wire by using a wire stripper or sharp knife to remove around half an inch. By doing this, the internal conductor will be made visible, enabling a solid connection with the spark plug.

Step 4: Slide on the Boot

Replace the spark plug boot that comes with your new spark plug after removing the wire. Make sure it covers any exposed bare metal and fits snugly over the exposed conductor. The boot aids in keeping moisture and dirt out of the engine, guaranteeing a consistent spark.

Step 5: Crimp the Terminal

The spark plug wire must be ready before it can be inserted into the terminal. The terminal must then be crimped firmly onto the wire. Strong connections that can survive the demands of engine operation are ensured by using the correct crimp. For a reliable and secure crimp, use a high-quality crimping tool made especially for spark plug wires.

5 Methods To Splice Spark Plug Wire

There are various methods for splicing spark plug wires, each with its own set of advantages and disadvantages. Knowing methods to splice spark plug wires correctly can save you time and money while ensuring your vehicle’s ignition system performs optimally.

Method 1: Using a wire stripper tool

Using a wire remover tool to splice spark plug wires can make all the difference. This useful tool enables precise and efficient wire stripping, resulting in a clean and secure connection.

You can locate the ideal wire stripper for your unique needs in a variety of sizes. You may reliably remove just the proper quantity of insulation without risking harm by simply changing the stripping blades to match the diameter of the wire.

Method 2: Using a crimping tool

A crimping tool is a convenient and effective way to connect spark plug wires. This helpful tool helps you to make solid and long-lasting connections between wires, ensuring that your spark plugs work optimally.

You can achieve professional-looking splices in no time by combining wire strippers and electrical tape with a crimping tool.

Method 3: Using heat shrink tubing

Begin by removing about half an inch of insulation from each end of the wire you want to splice with wire cutters.

Next, securely twist the exposed copper strands together and slip a piece of heat shrink tubing of sufficient size over the connection.

Then, using a heat gun or another heating source, such as a blowtorch, apply heat evenly to the tubing until it shrinks around the connection. Allow it to cool before checking the newly spliced spark plug wire.

Method 4: Soldering the wires together

One dependable and long-lasting method of splicing spark plug wires is to solder them together.

To begin, remove approximately 0.5 inches of insulation from every wire and securely coil them together.

After that, heat the wires with a soldering iron until the solder melts and forms a firm bond, applying flux to the twisted area.

By using this technique, a strong connection that can tolerate the harshness of heat changes and engine vibrations is guaranteed.

Method 5: Using electrical tape as a temporary solution

While it is not a permanent solution, utilizing electrical tape can help you get your vehicle back on the road quickly.

Begin by cutting the broken piece of the spark plug wire, leaving enough length on both ends for splicing.

Next, remove about an inch of insulation from each end and securely twist them together.

Wrap multiple layers of electrical tape around the exposed wire to establish a solid connection.

While employing electrical tape as a temporary fix may appear to be an unconventional method, it can be a reliable stopgap in emergencies. Here is the video that help you to understand better


1. Why would I need to splice a spark plug wire?

You may need to splice a spark plug wire if it is damaged, or worn out, or if you want to customize the length for your specific needs.

2. What tools do I need to splice a spark plug wire?

You will typically need wire strippers, electrical tape, heat shrink tubing, and a heat gun or lighter.

3. How do I identify which wires need to be spliced?

Inspect the spark plug wires and look for any visible signs of wear, fraying, or damage. Additionally, check for inconsistent performance or misfires in your engine.

4. Can I splice any type of spark plug wire?

Yes, you can splice most types of spark plug wires as long as they are compatible with your vehicle’s ignition system.

5. Can I just replace the entire spark plug wire instead of repairing it?

Yes, replacing the entire spark plug wire set is an alternative option when dealing with multiple or severe cuts in the wires.

6. Can I use force to remove stuck spark plug wires?

While it’s tempting to use force, it is not recommended as it may damage the wire or other components. There are safer methods available to help loosen and remove stuck spark plug wires.

Conclusion: Choose the best method for your needs.

Finally, splicing a spark plug wire is a quick and low-cost solution to repair and maintain your vehicle’s ignition system. Anyone with the necessary equipment and resources may execute this activity effectively. It is critical to carefully follow the instructions to achieve a strong and tight connection. Inspecting and replacing damaged or old spark plug wires regularly will assist in enhancing engine efficiency and prevent failures. So don’t be afraid to give it a shot the next time you detect a problem with your spark plug wires – learn how to splice spark plug wires to save money and keep your car operating smoothly!

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