Spark plugs are an essential component of your car’s engine as it handles the task of igniting the fuel in the engine. If you don’t inspect them from time to time spark plugs can become dirty, damaged, or worn which might cause several problems.

But don’t worry because we’re going to show you how to test a spark plug with a screwdriver. It might sound offbeat, but believe me, it’s possible.

Let’s get started (:

Why Is It Important To Test Spark Plugs?

As we said earlier, spark plugs play a significant role in igniting the air-fuel mixture which causes the engine to run. If they’re not doing the task properly you might notice that your vehicle’s engine is poorly starting or not starting at all.

If you use your car or any vehicle that has a spark plug for years without inspection, chances are it will become dirty, worn, or damaged, and if that happens then it will cause many issues including things like:

  • Misfires
  • Poor fuel economy
  • Increased emissions
  • Rough idling
  • Hard starting
  • Engine knocking

For this reason, Keeping an eye out on the vehicle, inspecting and making sure the spark plug is in good condition is a must. If you start to notice some of the signs we mentioned above then maybe it’s time to conduct a test and take the necessary steps to fix it.

How To Test A Spark Plug With A Screwdriver? (Step By Step)

Test A Spark Plug With A Screwdriver

So, you’re ready to dive in, grease your palms, and explore the nitty-gritty of testing a car’s spark plugs with a screwdriver?

Great! This method, while unconventional, has been a reliable fallback for many car enthusiasts and DIYers. While the process may seem complex at first, breaking it down into manageable steps will make it far less daunting.

Step 1: Locating The Spark Plug

Our first port of call on this journey is locating the spark plug. The spark plug can usually be found on the engine block. On a four-cylinder engine, they are typically lined up along one side.

V6 or V8 engines might have spark plug wires on both sides. Each spark plug will be attached to an ignition wire leading to the ignition coil or distributor.

Once you’ve spotted the spark plug, let’s move on to the next phase of our adventure.

Step 2: Carefully Remove the Spark Plug

Once we’ve located the spark plug, it’s time to remove it. But beware, this is not a step to be taken lightly. Spark plugs need to be treated gently, like a well-wrapped gift that you’re excited to open.

First, disconnect the spark plug wire attached to the spark plug – pull on the boot, not the wire. Then, using a spark plug socket, turn the plug counterclockwise to loosen it.

After that, you can unscrew it by hand. If it feels like a loose spark plug, it might already indicate a problem. It’s as simple as that!

Step 3: Inspecting The Spark Plug

Before we delve into the thick of the inspection process, let’s understand why it matters. Inspecting the spark plug is akin to a doctor’s preliminary examination.

It helps you identify visible signs of wear and tear or damage, enabling you to gauge the health of the plug. This, in turn, assists in making an informed decision about whether to clean, repair, or replace the bad spark plugs.

Make sure you inspect the ceramic insulator – it should be a light tan or grey color. If it’s black or oily, that could be a sign of a problem.

Another thing to note down is any other unusual observations. Cracks in the ceramic insulator, sooty deposits, burnt electrodes, or heavy carbon build-up are signs of a bad spark plug.

Keeping a keen eye for these details will help you decide if the spark plug is in good health or needs some tender loving care.

Step 4: Preparing For The Testing Phase

By performing the test, we can assess the spark plug’s ability to ignite the fuel-air mixture in the engine’s combustion chamber — the spark plug’s primary function.

Let’s get our spark tester ready and get started.

Before we launch into the screwdriver test, we need to make sure we’re properly geared up. Safety comes first, so put on a pair of insulated gloves and safety glasses.

Connect the plug wire back to the spark plug. Then, using a pair of insulated pliers, hold the threaded portion of the spark plug against a metal part of the engine.

Now, we’re ready to roll with our ignition system check.

Step 5: Conducting The Test

To perform the test, have someone crank the engine while you watch the gap between the spark plug’s electrode and the metal part of the engine.

If you see a strong blue spark, congratulations! Your spark plug passed the test. If the spark is a weak spark, well, we have a problem.

What Are The Indications Of Faulty Spark Plug?

The Good Spark plug: a strong blue spark between the electrode and the engine metal means your spark plug is in tip-top shape.

The bad Spark plug: if the spark is weak, yellow, or nonexistent, your spark plug is faulty. Also, any physical damage, heavy deposits, or worn electrodes you noted earlier can indicate a problematic plug. In this case, your ignition coils might also be at risk.

How To Deal With A Bad Spark Plug? (Explained)

Well, the results are in, and it looks like our spark plug didn’t fare too well. Don’t worry; it’s not the end of the world. Whether it’s attempting to clean and repair the spark plug or replacing it altogether, we’ve got strategies to cover it all.

Dealing with a faulty spark plug can be compared to standing at a crossroads. On one side, you have the option to salvage it by cleaning and repairing it.

On the other, you have the option to replace it with a new spark plug. Both roads have their advantages, and deciding which to tread often depends on the spark plug’s condition and your willingness to either put in the effort or shell out some cash.

Option 1: Cleaning the Spark Plug

In some cases, a faulty spark plug might just need a good cleaning. Use a wire brush or spark plug cleaner to remove any deposits and check if this fixes the problem. Sometimes, a little TLC can go a long way!

If you’re interested in trying this option then check out this article on how to clear spark plugs for more in-depth cleaning methods.

Option 2: Replacing the Spark Plug

If cleaning doesn’t help or if the spark plug is physically damaged, it’s time to say goodbye. Remember, a faulty spark plug can hinder your engine’s performance, so it’s better to replace it sooner rather than later.

Replacing a spark plug

How To Go About Replacing A Spark Plug?

If your spark plug has performed its last act and it’s time to take a bow, we move on to replace it. In essence, this process is the equivalent of removing the old and ushering in the new.

It’s about ensuring that your engine continues to perform optimally with a new, healthy spark plug. It’s crucial, however, to replace it correctly to avoid potential engine problems down the line.

Know Your Choices: Choosing the Right Replacement

Choose a replacement spark plug that matches the specifications in your vehicle’s manual. It’s like finding the perfect shoe size – it needs to be just right. Different vehicles have different requirements, so make sure you choose wisely.

Full Circle: Steps for Replacing the Spark Plug

To replace the spark plug, you follow the removal process in reverse. Screw in the new plug by hand first to avoid cross-threading. Then use the socket to tighten it. Connect the wire back to the spark plug, and voila! You’ve successfully replaced a spark plug.

To learn more details about replacing a spark plug, check out this article.

Further Reading:

The Bottom Line

There you have it – your comprehensive guide to testing a spark plug with a screwdriver. Remember, being able to inspect and test your spark plug is a handy skill that can save you time and money in the long run. Plus, it’s a pretty nifty party trick.

This was just one method to test your spark plug with a screwdriver. You can also use a multimeter to check the resistance or a spark plug tester tool designed specifically for this purpose.

There’s more than one way to skin a cat, and this holds true for spark plug testing as well.