Bad Spark Plug Indications: What You Need To Know

bad spark plug

A good spark plug ignites the fuel and air mixture consistently and efficiently. It is screwed on the cylinder’s head to deliver the spark for ignition. While a bad spark plug interrupts combustion process and effects engine performance.

The main function of a spark plug is to utilize high voltage energy to generate a very quick and violently hot spark. Therefore a good spark plug must have a superior covering among its different components. It assures high voltage will not run off and short out.

Proper firing of spark plugs occur when they acquire 12,000 to 25,000 Volts or even more. Although modern plugs can touch upto 45,000 volts. Higher current results in hotter and longer duration spark.

Bad Spark Plug: Indicators

We shall dicusss in detail, the indications of bad spark plugs. In this article we shall limit ourself to bad spark plug’s indications and prevention. There can be other reasons for below given problems.

1. Engine Misfires

A deficient combustion cycle results in engine misfires. Dirty or worn spark plug prevents firing on the engine’s cylinder. You can face jerky drive or brief power loss.

Prevention from Bad Spark Plug

Frequent inspection and cleaning of spark plugs is necessary. Replace after certain driven miles as recommended by manufacturer. It will also enhance lifespan of engine.

2. Slow Acceleration:

Bad spark plug is major reason, if you press accelerator and face sluggish acceleration behaviour. It may be due to fouled or defective spark plug. Faulty spark plug results in incomplete combustion and drops fuel economy.

Troubleshooting

Check the spark plugs for erosion or disfigure. Replace them if it is necessary.

3. Bad Fuel Economy

Bad spark plug leads to bad fuel economy. It create misfires. In result, incomplete combustion occurs which leads to poor fuel economy. It can go as high as 30% of fuel wastage.

Savings Tip: Avoid Bad Spark Plug

Replace spark plugs before their recommended life. It will give you benefit in fuel cost cutting. Peace of mind on the way is extra benefit.

Suggested Reading: Bad Fuel Economy: What You Need to Know

4. Engine Knocking

Engine knocking is a drastic form of engine misfiring. It is one of the major sign of bad spark plugs. Rough and anoxious sound when running at idle can’t be ignored. You may feel vibrations due to engine knocking.

Prevention Advice

Never compromise on spark plugs replacement if found faulty. Engine knocking leads to ultimate failure of engine. Always remain proactive in these matters to save on heavy repairs.

5. Trouble Starting Engine

When you face trouble in starting car, first thing comes in mind is a dead battery. An empty fuel tank may be a cause. However a possibility of bad spark plug is there which is preventing normal start of car.

Troubleshooting: Bad Spark Plug

Check order of the plugs, correct order is mandatory for optimal performance. Reccomended type of plug should be used for your specific car. Spark plug caps must be properly installed for proper connection. Dirty plugs should be cleaned if required repalce them.

6. Rough Idling

As you stop your vehicle at a signal and it is making too much abnormal noises there may be something bad with spark plugs. You may face even the situation as your vehicle want to quit its position and want to go home. Rough idling due to bad spark plugs should be immediately fixed.

7. RPM Fluctuation

Faulty spark plug leads to fluctuations in RPM. Spark plugs manage firing the fuel with piston. You may face slow acceleration if these are about to worn out completely. It is due to misfires in the engine.

Operating income of NGK Spark Plug Co., Ltd. from fiscal year 2013 to 2022 (in billion Japanese yen)

https://www.statista.com/statistics/1052483/ngk-spark-plug-operating-income

Have a look at the day by day growing demand of spark plugs. Above given statistics are representing operating income of the only one company.

Bad Spark Plug: Why?

A spark plug become bad before time, there are many resaons. We are giving some major causes below.

  • Overheating: Continual overheating of spark plug tip can lead to failure before time.
  • Cleaning Negligence: A dirty spark plug that is covered by many substances like oil, burnt fuel or carbon remains too hot during running. This occurs due to negligence in periodic cleaning.
  • Engine Oil Leakage into Combustion Chamber: Tip of the spark plug gets dirty if engine oil leaks into combustion chamber. It causes plug failure befor the time.

Lifespan of Spark Plugs

There is no hard and fast rule about life of a spark plug.

  • Conventional / Classic Spark Plugs: Their lifespan exist between 30,000 to 50,000 miles. But you should replace on 30,000 miles for optimal performance.
  • Platinum / Iridium Spark Plugs: These can be driven efficiently between 60,000 to 80,000 miles. Try to replace at lower limits. It will reduce wear and tear and saves your money.

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