The ignition coil is essential for the engine to work properly. Without it, there is no spark at the ignition plugs.
When this component fails, the engine’s performance can be compromised. As a result, problems arise such as acceleration failures, increased fuel consumption and difficulties in igniting the vehicle.
Explore in this article everything you need to know about how this component works, what the main symptoms of failure are and how to test it.
What Is An Ignition Coil?
The ignition coil is an electrical transformer that converts the low voltage of the car battery (around 12V) into the high voltage (between 15,000V and 45,000V) needed to generate the spark that ignites the air-fuel mixture inside the engine cylinders.
This process is essential to ensure the correct functioning of the combustion engine.
What Does The Ignition Coil Do?
The ignition coils main function is to ensure that the electrical energy from the battery is converted into a spark strong enough to ignite the fuel and air mixture inside the combustion chamber.
Without an efficient ignition coil, the engine can misfire, lose power or stop working altogether.
How Does An Ignition Coil Work?
To create a leap of fire in the spark plug, the battery voltage needs to increase thousands of times. For example, if the voltage is 12V, there can be no flame on the electrode of the spark plug.
Like transformer boosters, the ignition coil uses magnetic induction to increase the input voltage.
To do this, it has two coils inside:
- Primary Ignition Coil: surrounds the secondary coil and receives the initial current;
- Secondary Ignition Coil: is located inside the primary coil and is responsible for amplifying the voltage and sending it to the spark plugs.
How Is The Ignition Coil Induced?
Induction occurs through a process of converting electrical energy:
- The low-voltage current passes through the primary winding of the coil;
- When the current is interrupted, a magnetic field is created which induces a high voltage current in the secondary winding;
- This high-voltage current is sent to the spark plug, where it generates the spark needed for combustion.
What Is The Function Of The Iron Core In The Ignition Coil?
The iron core of the ignition coil concentrates and amplifies the magnetic field generated in the primary winding.
This increases the efficiency of the induction process and ensures that the voltage generated is high enough to ignite the engine.
What Are The Types Of Ignition Coils?
Depending on the car and brand, you can find the following types of coil:
Distributor Ignition Coils
Distributor ignition coils generate a high-voltage impulse that is transmitted via an ignition cable to the mechanical ignition distributor.
This in turn directs the voltage to the corresponding cylinder. This type of coil is more common in older vehicles.
Block Ignition Coils
Block ignition coils have several individual coils that feed directly into the spark plugs.
The voltage is transmitted via the individual outputs and the ignition cables.
They can be divided into two main types:
- Single Spark: each coil generates a spark for a single cylinder;
- Double Spark: each coil generates sparks for two cylinders simultaneously.
Orifice Coils For Spark Plugs
These coils connect directly to the spark plug, eliminating the need for ignition cables.
As the high-voltage pulse is generated directly in the spark plug, the loss of energy caused by the cables is avoided. It also optimizes space in the engine.
Ignition Coil System (Rails)
This system combines several ignition coils in a single compact component.
All the ignition elements are connected to the spark plugs simultaneously, simplifying installation and reducing the need for additional cables.
What Are The Common Causes Of Ignition Coil Problems?
This component is essential for the engine to function. However, it can break down over time.
The main causes of coil failures include:
1. Natural Wear And Tear
With continuous use, the internal components of the ignition coil can deteriorate, which reduces ignition efficiency. As a result, engine failures can occur.
2. Overheating
High temperatures in the motor can affect the coil, leading to insulation degradation and the risk of an internal short circuit.
3. Vibrations
Constant exposure to vibrations can loosen internal and external connections, impairing the transmission of electric current.
4. Moisture And Water Infiltration
The presence of water can cause corrosion on the coil terminals, which compromises performance and can lead to total failure.
5. Electrical System Problems
Irregular voltage or alternator faults can overload the coil. As a result, it reduces its lifespan and affects the engine’s performance.
6. Worn Spark Plugs
If the spark plugs are in poor condition, the coil needs to generate a higher voltage, which accelerates their wear.
What Are The Signs Of A Bad Ignition Coil?
If the ignition coil is faulty, the symptoms that can appear in the vehicle are:
- Strong burning smell;
- Engine vibration at idling;
- Increased fuel consumption;
- “Check Engine” signal on the dashboard;
- Heavy engine start, which stagnates when driving;
- Engine running unsteadily, especially in cold weather;
- Release of black smoke with a fuel smell from the exhaust manifold;
- Decrease in engine power when pressing the accelerator.
How To Test The Ignition Coil?
To test the ignition coil, you can use a multimeter. The procedure involves:
- Check the resistance of the primary and secondary windings: it must be compatible with the values recommended by the manufacturer;
- Perform a spark test: connect the coil to a spark plug and check for spark;
- Use an oscilloscope: in specialized car repair shop, this tool allows a more precise analysis of the coil’s performance.
If the ignition coil shows a reading of zero on the multimeter, this is a sign that it has internally short-circuited in the primary windings. In other words, it needs replacing.
How Long Does An Ignition Coil Last?
The lifespan of an ignition coil can vary between 60,000 km and 120,000 km, depending on the model and the vehicle’s conditions of use.
When Should I Replace The Ignition Coil?
You should replace the car’s coil when there are clear signs of failure or as recommended by the manufacturer.
Which Tools Are Best For Replacing The Ignition Coil?
To replace the ignition coil safely and efficiently, it is essential to use the right tools. Here are the main ones:
- Drive Socket Or Socket Wrench: to remove the screws securing the coil;
- Screwdriver Or Philips Screwdriver: used to loosen electrical connectors or brackets that hold the coil;
- Multimeter: essential for testing the voltage and resistance of the ignition coil before and after replacement.
- Nose Pliers: help remove electrical connectors without damaging the terminals.
- Protective Gloves And Safety Glasses: ensure user safety when handling electrical parts.
How Should The Ignition Coil Be Repaired?
Repairing the ignition coil can be done in some cases, but most of the time, replacing the component is recommended to avoid future failures.
If the coil only has a bad contact or is dirty, it can be cleaned and reinstalled.
To do this safely, you should contact an car repair shop.
Can You Still Drive With A Bad Ignition Coil?
A faulty coil can cause engine failure, increase fuel consumption and lead to more serious damage, such as problems with the catalytic converter and ignition system.
You should therefore replace this component as soon as you notice any anomalies.
How Much Does It Cost To Replace An Ignition Coil?
The price of an ignition coil varies according to the vehicle model and the type of coil.
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