How to Put Spark Plug Wires in the Correct Order

Engine spark plugs are the smallest component of your car but greatly affect how well your engine will run. You should replace a vehicle engine every 80,000 miles. However, if your vehicle uses ceramic units, then you can replace them after 100,000 miles. There are several things that you, as a car owner, should learn about the engine. One of them is how to put spark plug wires in the correct order.

Sometimes you may get yourself in a situation where you need to replace the spark plugs, and you cannot find a mechanic. It may initially sound like a complicated process, but it will be quite easy with the right information. Here is a guideline on how you can put the engine spark plus in good order.

Things you will need:

How to put spark plug wires in the correct order: Step by step guide

Putting spark plug wires is an easy process, but you need to be very careful. If you place the spark plugs wrongly, then it will affect the performance of the engine. If your mistakes are more severe by interchanging more than two plugs, the engine will not start. This guide helps one to answer the question of what order do spark plug wires go in. 

You should follow the process of putting spark plugs step by step. The distributor cap sends electricity according to the firing order of the engine. Each spark plug gets the electricity at a specific time when the piston located on top of the cylinder compresses the mixture of air and fuel. 

The role of the spark is to ignite the mixture and cause combustion. If the vehicle has crossing spark plug wires, the spark plugs get the heat at the wrong time. This means that the process of combustion does not happen, and the engine won’t run. Here are basic steps on how to connect spark plug wires in the correct order:

Get the owner’s manual for your specific car

One thing that will make your repair process easy is by having a car owner’s repair manual. Some of these repair manuals are also available online. You can also find and use one online.

In the owner’s manual, you will find a spark plug wire diagram and the firing order. With the right guide, the process of connecting the wires will take barely 2 minutes. In case you don’t get the owner’s manual, then follow the steps below:

Check for the distributor rotor rotation

Start by removing the distributor cap. This is a big round part where all four spark plug wires are connected. The distributor cap is located in the front or at the top of the engine. It is held in place tightly by two latches. Remove the latches using a screwdriver.

At this point, use a marker to make two lines. Make one line on the cap and another on the distributor’s body. You then put the cap back in the same place. Under the distributor cap, you will find the distributor rotor.

The distributor rotor is a small part that will turn each time the vehicle’s crankshaft turns. Crank it and see in which direction the distributor rotor will turn. The rotor can either go clockwise or counterclockwise but will not move in both directions.

distributor cap diagram
Image Source: vanpeltsales

Locate the number 1 Firing Terminal

In most cases, the number 1 spark plug distributor cap has a mark. If not, you will have to look at the owner’s manual or find any difference between one and the other firing terminals.

Luckily most manufacturers, however, will mark the number one terminal. You will see number 1, first, or something else written on it. This is the wire which connects the firing terminal in question with the first spark plug firing order.

Connect the number 1 Firing Terminal to the first Cylinder

Link the number one firing terminal with the first cylinder on the engine. But, this is the first cylinder in the spark plug firing order. This cylinder can be the first or second on the block. In most cases, it will have a marking but if it doesn’t have, consult your owner’s manual.

One thing you need to know is that only petrol-powered cars have spark plugs. Diesel vehicles use pressure to ignite the fuel. Your car usually has four spark plugs. Each one is reserved for one cylinder. Some cars may have two spark plugs per cylinder. This is common in some Alfa Romeos and Opel cars.

If your car has them, you will basically have twice as many cables. You need to connect the wires using the same guide but add another cable to the suitable spark plug. What this means is that terminal one will send two cables to cylinder one. The timing and the rotation remain the same as those with one spark plug

Connect all the spark plug wires

This last step is a little bit complicated. To make it easy, you need to understand the spark plug wire identification numbers. By now, you know that the first firing terminal is different from the others, and it is connected with the first cylinder. The firing order is usually something like 1, 3, 4, and 2.

This can be different from one car to another, especially if your vehicle has more than four cylinders. However, the points and steps are always the same. Connect the wires according to the firing order on the distributor. Since the first spark plug is already connected, turn the distribution rotor once.

If it lands on terminal 3, connect the terminal with the third cylinder. The next terminal should be connected to spark plug 2, and the last terminal is connected to the spark plug and cylinder number 4.

Understanding the direction of the distribution order will help you to know the firing sequences of that distribution rotor. It is the same as the firing order of the engine. This answers how do you know which spark plug wire goes where.

An easier method to do this is to replace the spark plug wires, one at a time. Pull the old one from the spark plug and the distribution cap and replace it with a new one. Repeat the step for all 4 cylinders. This method is extremely simple, and you will not have to remove the distributor cap. However, if the wiring is mixed, then you have to use the guide above.

How to Put Spark Plugs in the Correct Firing Order YouTube Video:

Frequently Asked Questions (FAQs)

Q. Does Spark Plug Wire Order Matter?

The spark plug wire order matters a lot. In most cases, the wires are labeled with numbers that will help you match with the right cylinder. To avoid mixing up and placing spark plug wires in the wrong cylinder, it is prudent to replace them one at a time. Placing spark plug wires in the wrong order will affect the engine’s performance or prevent it from starting. 

Q. What Happens If You Put Spark Plug Wires on Wrong?

Putting spark plug wires wrongly will lead to cylinder misfires. The unburned fuel will flow to the exhaust, damaging the cat and O2 sensors after some time. If you place more than two wires wrongly, the vehicle will not start. If the engine runs, the vehicle will run roughly since the timing of the air and fuel combustion will not align with the 

Q. Are Spark Plug Wires Numbered?

Most of the spark plug wires are numbered. They mainly come in black, but you can also get them in yellow, orange, red and blue. If the wires are not numbered, you can lay them down, and the length will guide you. If you still cannot tell which is which, check the car owner’s manual, and it will guide you on the numbering of the wires. 

Q. What Is the Correct Firing Order?

The firing order of straight-four engines is 1, 3, 4, and 2. However, this can be different in some vehicles. At times the firing order can be 1,3, 2, 4, or 1, 2,4,3.  

Vehicles using more than 4 cylinders have different tiring orders. Straight five engines use a firing order of 1, 2, 4, 5, 3 to reduce the vibration of a rocking couple.

The straight-six engines use a firing order of 1, 5, 3, 6, 2, 4. This provides a perfect secondary and primary balance.  The firing order of most of the V6 engines which feature a 90 degrees angle between the cylinder banks are R1, L3, R3, L2, R2, L1 or R1, L2, R2, L3, L1, R3.

Vehicles using straight-8 cylinder engines use a firing order of 1, 6, 2, 5, 8, 3, 7, 4. Cadillac 472, 425, 368 and 500 V8 engines firing order is 1, 5, 6, 3, 4, 2, 7, 8.

Q. Will a Car Run With the Wrong Firing Order?

When the firing order is wrong, the vehicle may run, but it will not run properly. The wrong firing order makes the spark be delivered to the cylinder either when there is no air and fuel mixture or when the mixture is not properly compressed. In an extreme case, the engine will not start after turning the ignition. 

Q. Can You Mix Different Brand Spark Plug Wires?

Most spark plug wire manufacturers cross-reference with other brands, so it is okay to use wires from different brands. The engine will work the same as when you would have used wired from the same brand. However, when purchasing, it would be prudent to look for comfortably interchangeable brands. 

Conclusion

To successfully replace the spark plug wires, you need to understand the spark plug wire firing order. This guide will help you learn how to put spark plug wires in the correct order and complete the task within minutes. On average, you will need around 20 minutes to finish the replacement process.

Take your time and make sure that each spark plug gets the electricity according to the firing order. It may sound not very easy, but it is far from that, and all drivers can do it in their garage. You also need to learn the symptoms of crossed spark plug wires. This will help you know when something is wrong with the spark plugs and work on it immediately.

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Tito

Hi There, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I have been working as a mechanic for over fifteen years. I worked for a long time at Global Rebound Automotive companies (Toyota, TATA, BMW, Nissan, TVs, and Others ) as a Mechanic and Mechanics Supervisor.

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