What is a car coil?

In order to work, combustion engines need to complete four main pillars, including suction, compression, explosion and discharge. The electrical system is considered one of the main systems of the technical part of the car, which plays a significant role in producing the power required for sparking the spark plugs.

The most important functions of the ignition system include providing energy, explosion and proper combustion of gasoline. In fact, the detonation is done by the electrical system of the car.

One of the important parts of the ignition system is the coil. The coil provides the electricity needed for ignition from the car battery. Then, in order to form the sparking action, it increases the electric voltage.

It should be noted that the coil price fluctuates under the influence of the car model. In addition, coil troubleshooting is done using a diag device and a multimeter.

Application of coil in the car

The car coil acts as a booster coil to boost the voltage produced by the battery

In the power supply system, the coil is responsible for generating energy, sparking, power supply and ignition. A car equipped with an internal combustion engine requires 7000 to 25000 volts of electricity for ignition and combustion.

It is interesting to know that the maximum potential of electricity generation by a normal car battery is equal to 12 volts. In addition, it is likely that the amount of battery power production will be affected by various factors such as spark plug failure, improper fuel conditions, and battery life. Undoubtedly, a normal battery alone is not capable of creating a spark by means of candles.

In other words, the amount of electricity that flows from the battery is very weak and it is not considered a suitable option for lighting car candles.

In this way, the coil, as a booster coil, amplifies the voltage generated by the battery and directs the required electricity to the spark plug at the right time to form the combustion process.

It is better to know that the basis of the work of the coil is based on the induction of electric current. This mechanical part increases the input voltage from the battery by means of an iron core and a coil according to the laws of magnetism and physics.

Car coil components

Main sections

central core

The main part of the car coil is the central core. The central core consists of a special type of alloy that is resistant to temperature increase. The material of the central core is mainly platinum alloys.

Normal car coils are responsible for arranging the sparks

The primary coil consists of 250 to 350 loops. This value of the number of turns of the wire plays a role in the formation of 3 ohm resistance. Meanwhile, the number of secondary winding loops is 15 to 30 thousand. In most cases, coil windings are made of copper. The primary and secondary windings are wound around a single core.

The electric current first goes to the primary winding with a low turn. It then creates the ground for electrical induction in the high-turn secondary winding. The transfer of electric current from the primary winding to the secondary winding increases the amount of electrical voltage thousands of times.

In the process of transferring and increasing the electric voltage, the coil converts direct current into alternating current


In most cases, the main body is made of aluminum and has a high heat transfer coefficient.

Ignition base

The number of spark plugs is determined according to the number of engine cylinders.

Insulation of coils

One of the components of the car coil is the insulation of the coils. In this structure, insulation is used to prevent heat damage to the coils.

It is interesting to know that the insulation of the coils is made of epoxy insulation material and is inserted between the coils. This part is effective in preventing the penetration of water, pollution, and dust into the housing of the coils.

Different types of car coils

In general, the car coil is produced in two types, with wire and without wire.

Coils with wire

Wire has been used in old cars. This mechanical part in the car mechanism is responsible for transferring electricity from the coil to the spark plug.

Double coils

Double coils are used in injection vehicles. Such coils adjust the ignition process simultaneously in cylinders one, four, two and three.

  • Normal coils

Normal coils are responsible for arranging the sparks. These types of coils are designed in a cylindrical shape and are used in carburetor cars.

Conventional coils arrange the sparks. It is interesting to know that normal coils are installed in the side part of a delco.

Wireless coils

In recent years, car manufacturing companies have completely removed the wire with the aim of speeding up the power transmission process and preventing energy wastage. In fact, in new designs, in order to avoid voltage drop and energy wastage, the coil is installed directly on the candle.

Pen or pencil coils

The work of the car coil is based on the induction of electric current

Pen coils are evident in modern injection cars. This type of coil is installed separately for each cylinder due to its high production voltage.

It is better to know that a pencil coil can increase the car’s power to 50 kW.

Book coils

The structure of book coils remains the same as double coils, with the difference that book coils do not have wires. The appearance of book coils is a bit wider than other types of coils.

Book coils are used in cars such as Peugeot 206 and Xantia.

Factors involved in car coil failure

The coil is prone to damage due to exposure to extreme heat. The breakdown of the coil prepares the ground for the interference of damage and the reduction of the performance of different parts of the car.

The most common effect of coil failure is the failure of the car engine.

In the following, we describe the factors involved in coil failure:

• Use of low quality coil

• Lots of heat and heat

• Improper operation of the car battery

• Failure to pay attention to the existence of a problem in the car’s electrical system

• Failure to change oil and pads on time

• Dirty air filter

• Theft of electricity in the car

• Connecting the wire head to the car body

Signs of car coil failure

oil leak

One of the symptoms of car coil failure is oil leakage. The car coil is installed inside a housing. When the coil is defective, its temperature increases significantly and it cracks, causing oil leakage.

It is possible that over time, the coil will wear out as a mechanical part. A worn coil conducts more high voltage electricity to the spark plugs than required. Undoubtedly, high voltage is associated with an increase in temperature, and by creating a gap in the coil, it leads to oil leakage.

Increase in fuel consumption

As we mentioned, the coil is involved in the ignition of the car by transferring high voltage energy to the spark plug. When the coil becomes defective, the energy needed by the candle is not provided, and instead, the energy of the candle is provided through fuel.

In addition, some fuel is sucked in every time the ignition is fired. When the car’s coil is damaged, much of the car’s fuel remains unused due to the lack of complete combustion.

Weak car starter

One of the common signs of car coil failure is a weak starter. When the coil is faulty, the electric current does not have the voltage required for ignition by the spark plug. Therefore, the act of sparking the candle is incomplete. In some extreme cases, the car engine completely loses its main function.

Vibration in the engine

Due to the failure of the coil, vibrations are formed in the engine and the car body. It is possible that the vibration of the engine caused by the defective coil is associated with the car gassing.

Among the signs of coil failure, the following can be mentioned:

• Turn on the check light

• Car ripping

• Incomplete ignition of the spark plug due to improper operation

• No spark formation in the cylinders

Car coil test

In order to be sure of the cause of problems such as car tearing, weak start, oil leakage and increase in fuel consumption, it is necessary to check the performance of the coil. To test the function of the coil, turn off the car first. Then by opening the hood, find the location of the coil.

After finding the coil, disconnect the wire connected to the spark plug and connect another spark plug and bring it closer to the body. Then start the saddle in the direction of ignition.

The blue color of the spark indicates the proper functioning of the coil. While the orange and purple color of the spark indicates the poor performance of the coil.

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