Spark plugs are the smallest component of your car that has the biggest effect on how well your engine will run. They need to be replaced after 80.000 miles or 100.000 if you get the ceramic units. But, you also have to know how to put spark plug wires in the correct order. This may sound complicated and it relatively is but we will help you get the job done as easy as possible.
Things you will need:
- Owner’s manual for your car
- Work light
How to put spark plug wires in the correct order: Step by step guide
In order to avoid spark plug wires wrong firing order and make sure all the cables are placed in the correct order you need to follow the guide below. If you make a mistake, the engine won’t work properly. If you make even more severe mistakes by switching two or more wires the engine won’t start. We will help you learn how to put spark plug wires in the correct order properly.
You need to understand why this is a mandatory process. The distributor cap will send electricity according to the firing order of the engine. Each spark plug will get that electricity at a specific time when the piston is located at the top of the cylinder and compresses the mixture of air and fuel. The spark is used to ignite the mixture and cause combustion. When we switch the wires in the incorrect order, a spark plug will get the electricity at the wrong moment, when the piston isn’t at the top dead point. There won’t be combustion and the engine won’t run. So how you can connect the wires into the correct order? Use the steps below.
Get the owner’s manual for your specific car
You can get the actual paper owner’s manual for your specific model and type of car. You can also find and use one online. The goal is the same. This isn’t a must, but we highly recommend you to use this step. When you have the owner’s manual you will simply see the firing order and the wiring diagram for the spark plugs. Connecting the wires is a 2-minute job in this case scenario. If you can’t find the owner’s manual or you don’t want to use it, you can get the job done using a more advanced method.
Check for the distributor rotor rotation
The first thing here is to remove the distributor cap. It is a big round part where all 4 spark plug wires are connected. Usually, it is located in front or top of the engine. The distributor cap is held in place with 2 latches and you can use a screwdriver to unlatch them. At this point is useful to use a marker and make two lines, one on the cap and another on the body of the distributor. You should put the cap back in the same place.
Under the distributor cap is the distributor rotor. It is a small part that will turn each time you turn the crankshaft in the car. Crank it and see in which direction the distributor rotor will turn. It can go either clockwise or counterclockwise, but won’t go in both directions.
Locate the number 1 firing terminal
Number 1 spark plug distributor cap might be marked. If not, you will have to look at the owner’s manual or to find any difference between one and other firing terminals. Luckily most manufacturers will mark the number one terminal. You can see number 1, first or something else. This is the wire which connects the firing terminal in question with the first spark plug in the firing order. More of this will be explained below.
Connect the number 1 firing terminal to the first cylinder
The firing terminal you located has to be linked to the first cylinder on the engine. But, this is the first cylinder in the firing order. It can be the first on the block or it can be second. You will need to see the marking on the engine if your car has it or you will have to use the owner’s manual. Remember that the firing order is completely opposite to the order of the cylinders!
Here we can add several useful things. First of all, as you already know only petrol-powered cars have spark plugs. Diesel vehicles use pressure to ignite the fuel. Your car will usually have 4 spark plugs. Each one is reserved for one cylinder. Some cars may have two spark plugs per cylinder. This was common on some Alfa Romeos and Opel cars. If your car has them you will basically have twice as many cables. All you have to do is to connect the wires using the same guide, but add another cable to the suitable spark plug. What this means is that the terminal one will send two cables to the cylinder one. The timing and the rotation remain the same as with one spark plug example.
Connect all the spark plug wires
The last step is a bit complicated. Now you know that the first firing terminal is different than the other and you know that it is connected with the first cylinder. Your firing order is usually something like 1, 3, 4, 2. It can be different and it will be if your car has more than 4 cylinders. Anyway, the point and the step is always the same. You need to connect the wires according to the firing order on the distributor. The first spark plug is already connected. Now you need to turn the distribution rotor once. It will land on the terminal three. Even if it isn’t market you will know that this is the terminal that has to be connected to the third cylinder. The next terminal should be connected to the spark plug 2 and the last terminal is connected to the spark plug and cylinder number 4. The step above told you to check for the direction of the distribution order. Once you know this, and you know the first firing terminal you can easily see all other firing sequences of that distribution rotor. In all cases, it is the same as the firing order of the engine.
There is a simple method you can use sometimes. If you are replacing the spark plug wires, all you have to do is to replace one at a time. Pull the old one from the spark plug and from the distribution cap and replace it with a new one. Repeat the step for all 4 cylinders. This method is extremely simple and you won’t have to remove the distributor cap or do anything else. But, if the wiring is mixed you will have to use the guide above.
Spark plug wire firing order is the only thing you will need to understand in order to successfully replace the spark plugs and the wiring. 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 without any additional help. Take your time and make sure that each spark plug gets the electricity according to the firing order. Your only mission is to match the firing order of the distributor to the cylinders. It may sound complicated but it is far from that and all drivers can do it in their own garage.
Learn More: Best Spark Plug Gap Tool