What Do The Spark Plugs Do? (1.5L Honda Civic)

What Do The Spark Plugs Do? (1992, 1993, 1994, 1995 1.5L Honda Civic And Civic Del Sol)

The spark plug is a small ignition system component but has a very tough job to do, which is to deliver the spark that will ignite the air-fuel mixture and start the combustion process inside its engine cylinder.

The spark plug will eventually fail, and this article will answer some of the most commonly asked questions about the spark plugs.

APPLIES TO: This tutorial applies to the following vehicles:

  • 1.5L Honda Civic: 1992, 1993, 1994, 1995.
  • 1.5L Honda Civic Del Sol: 1993, 1994, 1995.

What Does A Spark Plug Do?

In a nutshell, the spark plug's job is to ignite the air-fuel mixture within the cylinder it's connected to.

It does this by transmitting the ignition coil's spark from its center electrode to its side electrode.

The process of spark jumping from its center electrode to its side electrode continues the whole time the engine is running.

Symptoms Of A Bad Spark Plug

Spark is one of three things the engine cylinder needs to produce power (the other two being air and fuel).

If spark is missing, that cylinder will misfire because the spark plug isn't providing it.

Here's a basic list of the symptoms you'll see when a spark plug stops functioning:

  • Rough idle.
  • Bad gas mileage.
  • Extended engine cranking (engine takes longer than usual to start).
  • A heavier than normal exhaust smell coming out of the tailpipe.
  • The engine is not as peppy as it used to be.
  • Hesitation when you accelerate the vehicle on the road.

What Causes A Spark Plug To Stop Working?

There isn't one single issue that will cause the spark plug to stop sparking.

The most common issues that'll keep the spark plug from sparking are:

  • Normal wear and tear. In other words, they simply wear out.
  • Carbon deposits blocking the air gap between the center and side electrodes.
  • Damage caused by the installation process (like for example during a tune-up).

Carbon deposits blocking the spark plug's electrodes are usually caused by engine oil that's burning inside the cylinder the spark plug is connected to.

You can easily identify an oil-burning engine because:

  • They have blue smoke coming out of the tailpipe (when the engine is running or when under load).
  • They need to have engine oil added on a regular basis.

How Do I Know My Spark Plugs Need Changing?

Since a spark plug can stop working for various reasons, there's not just one thing that'll let you know it's time to replace them.

Generally, you'll replace the spark plugs because:

  • You've removed them and are showing signs of heavy wear and tear.
  • They're causing an engine performance problem.
  • You're following a recommended spark plug change interval.

Which Spark Plugs Should I Buy?

Your Honda Civic was outfitted with NGK spark plugs when it left the factory.

If it's time to replace them, these are the spark plugs that I recommend you replace them with.

Having said that, you can buy and install any spark plug brand. As long as those spark plugs are specifically designed for your 1.5L Honda Civic, they'll work just fine.

Should I Use 100,000 Mile Spark Plugs?

Spark plugs advertised as having a service life up to 100,000 miles have platinum or iridium-tipped electrodes. Regular spark plugs, which have copper electrodes, do not last that long.

The catch here is that if the engine is in perfect working condition (e.g., it's not burning oil), these spark plugs will give you a service life of about 100,000 miles.

But if you got a high mileage engine that is burning oil, you're not going to see anywhere near 100,000 miles on those spark plugs. Carbon buildup will eventually close the air gap between the spark plug electrodes and cause a misfire.

Important Tips And Suggestions

The following replacement tips will help you avoid complications when replacing the spark plugs on your 1.5L Honda Civic:

TIP 1: Replace the spark plugs with a completely cold engine. The cylinder head on your Honda Civic's 1.5L engine is made of aluminum. This means that you've got to remove the spark plugs from a completely cold engine.

Why? Because you run the risk of damaging the spark plug hole threads if you remove the spark plugs from a hot engine.

Trust me; this is a nightmare that you want to avoid!

TIP 2: Check the air gap of the new spark plugs with a spark plug gapper.

TIP 3: Use a torque wrench to tighten the spark plugs. If you don't tighten the spark plugs enough you run the risk of having them come out as you're driving down the road. This could also damage the spark plug hole threads in the cylinder heads.

If you over tighten the spark plugs, then you run the risk of damaging the threads of the spark plug hole.

The way to avoid any of these problems is to use a torque wrench to tighten the spark plugs.

More 1.5L Honda Civic Tutorials

You can find a complete list of 1.5L Honda Civic tutorials in this index:

Here's a small sample of the tutorials you'll find in the index:

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Honda Vehicles:

  • Civic 1.5L
    • 1992, 1993, 1994, 1995
  • Civic del Sol 1.5L
    • 1993, 1994, 1995