SUMMARY

The primary function of a spark plug is to ignite the air/fuel mixture within the combustion chamber under all operating conditions. Spark plugs must provide a path and direction for electrical energy from the ignition coil, to create a spark used to ignite the air-fuel mixture. A sufficient amount of voltage must be supplied by the ignition system to spark across the spark plug gap - this is called Electrical Performance. The spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling - this is called Thermal Performance.

common faults

1. Rough engine idle - Engine idling is wherein the vehicle is stationary with the engine remaining switched on. An ordinary symptom of a bad spark plug, rough idling exists when the engine stumbles. There is also an escalation in the vibration of the vehicle. Not checking the symptom in time could lead to severe damage, which in turn could prove to be very expensive.


2. Hard to start - This is one of the most common symptoms of a bad spark plug. Even after several attempts, the spark plug fails to produce the spark necessary for the vehicle to kick over then there may be a possibility that the battery is running dead due to a faulty spark plug/s, and hence needs to be replaced at the same time.


3. Engine surging - In such a situation the vehicle slows down after giving sudden jerks. The engine starts and stops all of a sudden, hindering movement. Also known as engine hesitation, the engine sucks in more air thereby interrupting the acceleration of the vehicle. Surging in busy traffic can prove to be very dangerous.


4. Engines misfires - When your engine misfires it causes the vehicle to halt for a fraction of a second and then continues in its usual movement. This means the vehicle is not functioning as smoothly as it should because one or more cylinders are not firing properly and will also lead to higher amounts of emissions.


5. High fuel consumption - If your spark plugs have deteriorated you will notice that your vehicles fuel economy can decrease by up to 30% due to incomplete combustion. If you notice poor fuel economy this could very well be the spark plugs.