How to detect whether your vehicle spark plug is defective or not?

What to Look for When a Spark Plug Is Faulty

Spark plugs are one of the most important parts of any petrol engine. They'll simply transmit an electrical signal from the coil to the interior of the cylinder at a certain moment, which will ignite the air and fuel combination. As a result, it's critical to have them changed at a car service according to the manufacturer's recommendations. As faulty spark plugs could be a possible cause for an emissions test failure, look for the expiry date on an MOT check and have them replaced as and when required.

They can last anywhere from 30.000 to 100.000 miles, depending on your vehicle and the spark plugs themselves. They are doomed to fail. When this happens, you must figure out what's causing the issue. In this part, we'll go through the most common indications of a faulty spark plug. If you're still not sure, look up an MOT history check online and get any defective spark plugs replaced by a competent car technician.

The signs and symptoms of a faulty spark plug

There is no one indication that can teach you how to identify a faulty spark plug. To put it another way, you might have two or more symptoms, each of which is different. The following are all of the symptoms that your car might be experiencing:

1.     Engine misfiring 

The most common problem with a car's wiring is misfiring. When the combination of air and fuel in a cylinder is not ignited at the correct moment, it is called a misfire. The engine will function erratically, and you will hear explosions coming from the exhaust pipe. When the electrical signal from the coil is not transmitted to the sparkplug at the proper moment, or when the sparkplug fails to transfer it at the proper time, a misfire occurs. It can be transmitted when the piston in the cylinder is climbing or falling. In either scenario, you'll notice higher fuel consumption, difficulty starting the engine, and a drop in performance. Remember that a broken or defective sensor on the camshaft or crankshaft might cause a misfire. Your vehicle's onboard computer, on the other hand, will display a matching fault code. It may be a good idea to check MOT history and see if there was previously a pattern for the failed emissions tests.

2.     Surging engine 

In 99% of situations, this is a symptom linked with a defective spark plug. It's rather noticeable. While driving your car, you will notice a reduction in power and lower performance. When one or more spark plugs fail, this happens. A spark plug will start to operate when you apply the throttle and increase the RPMs.

3.     Idling vibrations 

When your engine is idle, it should be smooth and silent. It indicates that all of the components are in good working order. When a spark plug dies, though, you'll feel vibrations and a sluggish idle. The engine runs normally, and the vibrations stated before are visible. The symptom is typical when one or more spark plugs are malfunctioning.

4.     Fuel consumption increases 

This is a frequent symptom caused by defective spark plugs. So, what's the source of this? When the spark plug is broken or inefficient, it is unable to ignite the fuel and air combination correctly. Your car will consume more fuel as a result of the increased demand. An overly wide or inadequately tiny gap between the electrode and the centre portion of a spark plug might cause this symptom. The gap, which is measured in mm, is predetermined by the manufacturer. You'll need a tool to measure and modify the distance because each car has a different value. The problem can also be solved by replacing the spark plugs.

5.     Reduced acceleration 

This is one of the most prevalent problems. When the spark plug's efficiency is diminished, this happens. It is made up of various materials, all of which must work together to transmit the electrical signal to the engine at the precise moment. This will ultimately diminish, suggesting that the spark plug will either not deliver the signal at all or at a slower pace than is required. If no signal is sent, the cylinder will not work. Your car will only have three or fewer cylinders to run on. When efficiency is diminished, a spark plug may transmit an electrical signal at an inopportune moment or at a lower voltage, preventing the cylinder from producing power and resulting in reduced acceleration. A malfunctioning fuel injector, a sensor on your camshaft or crankshaft, or even a blocked fuel filter can all contribute to this issue. Starting with the spark plugs, especially if they're old, is a smart idea. The spark plug wires may also need to be replaced in rare situations.

6.     Your car's engine won't start 

Spark plugs need to be replaced if you're having problems starting the engine, especially when it's chilly outdoors. We should point out that, while this is one of the first symptoms to show, it does not always mean that a spark plug has failed. It means a spark plug (or several spark plugs) has broken and is no longer delivering the electrical signal properly.

You now know how to detect whether a spark plug is defective. Regardless of which or how many symptoms you have, you must examine and replace the spark plugs, which you may do by looking at trends in your MOT history. A simple repair will often be sufficient and your car will return to regular functioning. Keep in mind that your vehicle's spark plugs are the tiniest but most vital component.

As a result, it's simple to understand why upgrading to a higher-end spark plug is a good idea. They'll last longer and make it less likely than any of these symptoms will appear.