Which spark plug wires do I need?

Most manufacturers recommend an 8 or 8.5mm plug wire on most applications. Exceptions would be an all-out race car or a street rod where EMI/RFI suppression is not a concern, but weight and appearance are. In which case, a 5 or 7mm wire might be a better option.

How are spark plug wires connected in the correct order?

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.

What’s the number on the spark plug cap?

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.

What should I do if my spark plug is not connected?

If the engine of your vehicle backfires, turn it off immediately. After that, check if the spark plug wires are connected properly or not. You should always have your repair manual with you. That is one of the most important guides you can get to complete these procedures.

How many spark plugs are in a car?

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 should the resistance of a spark plug be?

If you get a higher reading than specified for your wires, replace all spark plug wires. Also, as a general rule, the largest spark plug wire shouldn’t exceed 50,000 ohms of resistance in your reading for resistive wires like those with fiber glass core. Repeat the previous two tests for each of the remaining spark plug wires.

What to look for in a spark plug?

Look for physical damage to the wires or boots, such as cuts and scorch marks. Use a flashlight or an area with good lighting to perform a visual inspection of the spark plug wires and the cap on top of them, called the boot.

Can a spark plug wire be cut to fit?

Spark plug wires are commonly direct-fit to work on a specific application. This makes installation very easy; however, you can also find universal spark plug wires that can be cut to fit. There are also a variety of color options and plug boot configurations (straight, 45-degree, 90-degree, etc.) to fit your particular needs.

How to test the conductor of a spark plug?

Old ignition system with mechanical contact breaker points. With this test, you’ll check the condition of the conductor that runs through the thick insulation of your spark plug wires. For this test, use a simple analog or digital ohmmeter. Set your meter to the ohms scale and to a setting that will let you read 50,000 ohms or above.