What is a Spark Plug and Why is it Important?

If you could look into one of your cylinders, you would see the tip of a spark plug. What is it, and what does it do? Read on to find out.

What is a Spark Plug?

Ford OEM spark plug

Screwed into the cylinder head, a spark plug is a tube-shaped electrical part with several major components:

  • Center electrode
  • Ground electrode
  • Electrical inference resistor
  • Ceramic housing

A spark plug draws energy from the ignition coil. The ignition coil produces electricity at very high voltage. The high voltage allows that spark plug to produce a spark in the cylinder.

Why Does Your Car Have Spark Plugs?

Spark plugs may be tiny compared to the rest of the parts in your car, but they’re actually some of the most important parts. Without spark plugs, your car won’t start or run.

The spark plug provides the spark needed to ignite the air/fuel mixture in the combustion chamber where it's situated. All the spark plugs in your engine work together to keep the motor running smoothly by taking turns igniting the air/fuel mixture in each cylinder.

How to Know if One of Your Spark Plugs is Bad

OEM plug

Spark plugs typically last about 50K miles. Once they wear out, they need to be replaced. The best way to find out if one of your spark plugs is worn out is to physically inspect it.

Routinely inspecting each spark plug can be a pretty time-consuming task. But the good news is that there are symptoms to tell you when it’s time to take a look. The sooner you detect the following symptoms and catch the problem, the better. Here are the symptoms of a worn spark plug:

  • Sluggish acceleration
  • Misfiring engine
  • Difficulty starting the engine
  • Increased fuel consumption

Here’s a set of instructions on inspecting your spark plugs and determining if any of them is bad.

To learn more about spark plugs, check out the following article: