An ignition coil, also known as a spark coil, is an induction coil used in spark ignition engines. This converts low battery voltage (12V) into the 40,000 volts needed to create an electric spark at the spark plugs and to ignite the fuel-air mixture in the engine cylinders.
In other words, the ignition coil has the role of an electrical transformer. It is a strong conductor. Some vehicles have more than one coil, they may have one coil for each cylinder/spark plug. Every time you turn on the key, a spark must be delivered to ignite the engine.
How do you check an induction coil?
The ignition coils have two circuits that require checking; primary and secondary circuits. Connect the multimeter to the negative and positive terminals of the induction coil to obtain a reading of the primary circuit. If the multimeter shows a reading of 0 ohms, the spark coil has shorted and needs to be replaced.
The average life of the ignition coil is about 160,000 km or more.
If you have a car with a lot of miles, you should replace the coils when you change the spark plugs, so you don’t have to come to the service twice.
Be aware that a vehicle that has a faulty induction coil may not start at all or run poorly with a lack of power. If the engine is not running well due to a coil, it can damage catalytic converters and oxygen sensors due to fuel entering the exhaust system.
VIDEO: What is the role of the induction coil
Ignition coils can be cleaned with WD40. They break down due to dirt and oil. They are mounted in one of the dirtiest parts of the engine.
If the ignition coil is not working properly, it will overheat. Overheating the ignition coils can hinder their ability to conduct electricity.
Ignition coil failure causes: The induction coil can fail from dirty or bad spark plugs.
What are ignition coil failure symptoms?
- Loss of power. This is one of the first symptoms of ignition coil failure,
- The check engine light is on,
- The car consumes more,
- The engine shakes,
- The engine stops shortly after starting
- Hard start
- Unburnt fuel detonates in the exhaust
Ignition coil types:
- Stick coil
- Distributor coil
- induction coil block
- Coil on the spark plug
Photo: Bosch ignition coil types
How much does an ignition coil cost?
Depending on the car model and brand, the price of a spark coil varies between 30 euros and 300 euros. The labor is around 100 euros.
The ignition coils, regardless of the car model, Honda Civic, Nissan Altima, Nissan Sentra, Opel Astra, BMW 3 Series, Audi A4, Ford Focus, or VW Golf, transmit voltage to the spark plugs, therefore they are different parts, but they work together. The ignition system consists of spark plugs, spark plug wires, and the ignition coil.
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What are the symptoms of a failing ignition coil?
- Loss of Power. This is one of the first symptoms of induction coil failure.
- Check Engine Light On.
- Poor Fuel Economy.
- Misfiring Engine.
- Hard Starts and Stalling.
- Spluttering and Coughing Sounds.
- Jerking and Vibrating.