What Does a Spark Plug Do?

Most people have heard of spark plugs but beyond periodically replacing them, may not know what they do exactly. Spark plugs are integral to the function of your engine. They provide one of the three essential components of combustion and despite their small size, are one of the most important parts of your car. 

What is Combustion?

The recipe for combustion, which is how your car creates power, can be split into three ingredients; air, fuel, and spark. 

The air comes from your vehicle’s intake. Air is sucked in through a filter and into the cylinders through the engine’s intake valves. 

Fuel is self-explanatory, and is injected into the cylinders and mixes with air to create a blend ready for combustion.

Without some sort of ignition though, this mixture won’t do anything. That’s where the spark plugs come in. They ignite the air-fuel mixture, creating an explosion. This explosion pushes the pistons down and turns the crankshaft. This power is then directed through the transmission to the wheels, allowing the vehicle to move.

What is a Spark Plug and How Does It Work?

A spark plug is made up of a center electrode, an insulator, and a ground electrode. The plug is threaded on the outside to allow it to screw into the cylinder head

Spark plugs create an arc of electricity that ignites the air-fuel mixture and causes combustion.. 

The electrodes create an arc of electricity that ignites the air-fuel mixture and causes combustion. This creates the power needed to push the pistons and in turn the crankshaft. 

Each cylinder has a plug, and each plug is used for every combustion cycle. Spark plugs are made to last a long time, but with constant use, they wear down and need replacement. 

Spark plug on yellow towel

What Happens if my Spark Plugs Need to be Replaced?

Spark plugs have long lives, usually lasting 30,000-50,000 miles before replacement. Higher quality iridium and platinum plugs can even last between 50,000 to over 100,000 in some cases. 

Old or faulty spark plugs can exhibit a variety of symptoms, ranging from barely noticeable to not even being able to start the car. 

Symptoms of bad spark plugs in the early stages can include:

  • Trouble starting the car
  • Check engine light
  • Reduced fuel economy
  • Rough idle

If left untreated or if the plug fails, the symptoms can be much worse. Some of these issues include:

  • Stalling engine
  • The engine won’t start
  • Sluggish acceleration
  • Loud noise from the engine
  • Flashing Check Engine Light (Stop driving immediately)
  • Damage to Catalytic Converter

What do I do if my Plugs Need Replacing?

If you notice any of these symptoms, it’s best to bring your vehicle to a professional for a diagnosis. Spark plugs are generally inexpensive and replacing them at the first sign of an issue can save you headaches down the line.

Spark Plug Service at Borst Automotive

If you’re in Arizona and are experiencing any similar symptoms, check out Borst Automotive!

Borst Automotive is your best bet for a friendly team and quality service. With four locations in Tucson, Mesa, and Phoenix, Arizona, there’s always a Borst ready for you and your vehicle. Call or schedule an appointment online today to secure a spot with our ASE-certified technicians.

Borst Automotive is here to help when you need it. Give us a call, schedule an appointment, or stop in today!