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Can Bad Spark Plugs Cause Engine Knocking

Yes, any spark plug malfunction can cause engine knocks. The reason is a spark plug is the only part of the whole ignition chain that has direct contact with the combustion chamber, pistons, pressure valves, and fuel.

To be precise, misfire or firing rate inconsistency creates multiple flames. Having more than one combustion at the same time in a single chamber makes shockwaves strike the chamber. As a result, you can hear unusual noises along with the regular engine sound.

What is Engine Knocking?

When a vehicle’s combustion chamber gets ignited not from spark plugs’ firings but from other malfunction inside the chamber, there’s a chance that both types of combustion can happen at the same moment.

The shockwaves created from collision of multiple combustions is what we refer to as engine knocks.

The major reasons why we get to hear engine knocking or pinging are:

  • Bad sparking plugs
  • Low-quality fuel
  • Weaker valves
  • Carbon coated combustion parts
  • Less heat ventilation

Why do bad spark plugs cause engine knocks?

Most of the time, engine knocks disappear by changing the old worn-out spark plugs. So, yes, a bad sparking plug is a common reason that makes weird engine noises. Let’s dig into those behaviors and conditions that make a bad plug the cognition behind this blunder.

Weak Sparkles

Weak sparkles fail to combust all of the fuel inside the combustion chamber. This leads to uneven burning of air-fuel mixture resulting in spark knock.

Inconsistent Firing

Inconsistent firing disrupts the harmonic combustion of fuel which can lead the engine to make knocking sounds.

Inaccurate Torquing

Plugging torques are not directly involved in knocking.

A huge gap between the piston and ignition point remains if you don’t torque the spark plug sufficiently. Loose spark plugs aren’t efficient enough.

Over torqued plugs can’t release the heat. Their firing pin and core gets red hot due to overheating. The rising temperature pushes the fuel to the autoignition point.

Carbon Fouling

Carbon fouling can happen anywhere in the combustion chamber. The most possible fouling affected places can be spark plugs and valves.

Carbon fouled plugs can leave small carbon particles in the air-fuel mixture. Those particles can make the mixture react and ignite automatically while consuming pressure.

Fouling can happen for several reasons. Unusual torque gaps, incompatibility, and slow chamber valves are some common reasons.

Riding style

If you accelerate too much having higher gears on eg. if you start accelerating from rest with 5th gear, engine knock will occur. So, to avoid spark knock, increase the rpm slowly and gradually.

Why do bad spark plugs cause engine knocks

What does spark knock sound like?

Suppose someone from outside is knocking at your door. How does it sound from the side you are on? The engine knocking sound is exactly the same. The shockwaves born from pressure wave collisions strike combustion chamber walls. The sound is like something is pinging under the bonnet when you sit in the car.

How to Fix Engine Knock?

Hearing engine knocks is not a serious problem, but it indicates something bad can happen to the engine’s health. If you hear clear ping noises from your vehicle, follow these tricks

A full tuning and cleanup of spark plugs at home can reduce the knocking sound to zero. Checkups are necessary every once in two weeks.

Always make sure there is no leakage in the connections. Connect every part properly with each other so that function gets the required sequence.

And lastly, don’t forget to use fuel with the necessary CH bond ratio.

Final Thoughts

Engine knock indicates that your car’s combustion chamber is having immense pressure. This will reduce the longevity of the engine.

Checking the spark plug regularly, using good quality gas, checking the valve and few other on the go checkups can save you from unwanted engine knocks.

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