What are Spark Plugs and How do They Work?

Every internal combustion engine has a set of spark plugs, with one plug in each cylinder. Why do spark plugs exist, though, and why does your engine need them? This article will tell you everything you need to know about spark plugs.

What is a Spark Plug?

Nissan spark plug

The spark plug is best described as the core of the internal combustion process. It’s a small tube-shaped part that delivers electrical current to ignite the fuel/air mixture. The main purpose of having spark plugs in your engine is to initiate the combustion process. Without spark plugs, your engine can’t start.

How Spark Plugs Work

A spark plug is made of a few parts:

  • Central electrode
  • Ground electrode
  • Resistor
  • Porcelain shell

When you start the car, the ignition coils sends high voltage current to the spark plugs. The car's ECU controls the order and timing of the ignition coils. The voltage is high enough to jump the gap between the central electrode and the ground electrode. This creates a visible spark, which ignites the fuel in the cylinder. This combustion, along with the energy from all the other cylinders, creates enough power to move the car.

How to Know if You’ve Got a Bad Spark Plug

Spark plugs will go bad over time. A bad spark plug greatly affects your engine’s performance and fuel economy. That’s why we recommend keeping an eye out for decreased engine performance once your car hits 40,000 miles. The following issues are telltale signs that one of your spark plugs has gone bad:

  • Poor acceleration
  • Decreased fuel economy
  • Misfiring engine
  • Difficulty starting the engine

Where to Find an OEM Replacement Spark Plug at Wholesale Pricing

OEM nissan spark plug

Have you determined that one of your spark plugs has gone bad using this diagnostic tutorial? The next step is to get an OEM replacement spark plug and replace it yourself. You could bring your Nissan to a dealership to have your bad spark plug replaced. But we recommend against it because the project is so easy to tackle at home.

Anyone who buys a replacement spark plug (or pretty much any OEM part) at a Nissan dealership pays a pretty big markup. If you’re looking to save money, you can order the exact same OEM spark plug from a trusted OEM Nissan parts seller. At NissanPartsPlus.com, we sell genuine OEM spark plugs at wholesale prices. This means our spark plugs are about 30% cheaper than the exact same ones sold at Nissan dealers all over the country.