(Note: this article is for general information and is not tied to any car brand)
Ignition coil tasks
The ignition coil stores energy and produces high voltage to create a spark at the spark plug electrode.
The function of the ignition coil is based on the law of induction: the ignition coil consists of a soft magnetic iron core, a primary winding of copper wire with a small number of turns (cross-section approximately 0.75 mm 2) and a secondary winding of copper wire with a large number of turns (cross-section approximately 0.63 mm 2). The turns ratio is approximately 1:200.
The energy supplied from the battery is disconnected from the final control stage at the required ignition moment. The magnetic field of the primary winding is transferred to the secondary winding. The voltage arising in the secondary winding depends on the number of turns. This high voltage is used to create a spark at the spark plug electrode.
Ignition energy
With an optimal mixture composition, the ignition energy should be approximately 0.2 mJ, with a leaner or richer mixture - approximately 3 mJ. However, in practice, energy consumption is much higher.
The generated energy in modern ignition systems reaches from 60 to 200 mJ. This means that contact with high-voltage parts may pose a risk to life!
Terms in the ignition system
Distribution
Energy storage: During the charging cycle, the coil stores energy in the magnetic circuit. Current is supplied - the coil is charged (the primary winding circuit is closed, the secondary winding circuit is open). At a given ignition moment, the primary circuit opens.
Primary current
Induced Voltage: Any change in current in the inductor (coil) changes the voltage. High voltage is generated again.
Secondary voltage
High voltage: Just like in a transformer, the high voltage produced depends on the number of turns of the primary/secondary coil. After reaching the required breakdown voltage, the coil is discharged to form a spark (breakdown).
Secondary current
Ignition spark: after high voltage arrives at the spark plug, the accumulated energy is discharged into the spark channel (the primary current circuit is open, the secondary circuit is closed).
Closing time (coil charging)
In the contact-distribution ignition system, the length of time during which the breaker contact is closed is determined.
The electronic ignition system prescribes the length of time during which the primary current flows. The primary winding of the coil is connected.
Ignition system with contact breaker
Electronic ignition system
VARIETIES OF COILS
In practice, there are mainly 3 types: an ignition system with a rotating distributor, a double-spark ignition coil and a single-spark ignition coil.
Standard Ignition Coil for High Voltage Rotating Distribution (ROV) Engines
Charge current control via breaker contact. Here, high voltage is generated centrally from one ignition coil and is mechanically distributed to the individual spark plugs by the ignition distributor. In modern engine control systems, this type of voltage distribution is no longer relevant.
Double-spark ignition coil (in engines with an even number of cylinders)
Both high voltage connections are connected in series to two spark plugs, the firing order of which is offset from each other by 360° of crankshaft rotation. The ignition coil generates an ignition spark simultaneously to two spark plugs: one is located in the cylinder in which the air-fuel mixture is compressed, and the second is in the cylinder, which at this time is on the exhaust stroke. In a high-pressure cylinder (with a compression stroke), a working main ignition spark occurs, in a less compressed cylinder (with a purge stroke), an idle ignition spark occurs. After 360° rotation of the crankshaft, everything becomes the other way around. In the other pair of cylinders, the ignition pulse occurs in exactly the same way, only shifted by 180° of crankshaft rotation.
Thanks to the series connection, one of both spark plugs operates with a positive high breakdown voltage, and the other with a negative voltage. Due to different voltage directions, spark plug electrodes show different burning patterns.
For each crankshaft revolution -2 ignition sparks (main/working spark and supporting/idle spark)
1. Interference suppression plug 2
. Ignition cables
3.
Connector 4. Double spark ignition coil 2x2
Static high voltage distribution with dual-spark ignition coil
Single spark ignition coil in a fully electronic ignition system
In this design, each spark plug is assigned to a specific ignition coil, which sits directly on the spark plug insulator. The design allows for more filigree designs and sizes. Single-spark ignition coils are installed on both even and odd numbers of cylinders: the ignition system is still synchronized by the camshaft sensor.
You don’t need to have any special automotive education to understand that every element included in the structure of the most common means of transportation - a car - even the smallest one, is very important, and in its absence, things can lead to disaster. The ignition system, and especially its true heart - the coil, does not fall into the category of exceptions. Therefore, it is so important to have an understanding of the design of the ignition coil and its operating principle. This will be discussed further.
The ignition coil (otherwise it can also be called a module) is one of the elements of the automobile ignition system, designed to convert low-voltage voltage from the on-board network into a high-voltage impulse. After this, the resulting high voltage causes a spark to form between the electrodes belonging to the spark plug and ignite the fuel-air system.
In general, this mechanism is a transformer that has two windings and can be used in all systems: electronic, contactless and contact. But depending on the type of coil, its structure is characterized by certain transformations. Let's look at these types and their structure.
- Many electronic ignition system designs may use a dual coil. Another name for it is two-terminal. This type has two high-voltage terminals, which cause two cylinders to simultaneously spark. Moreover, one of the cylinders is located at the end of the compression stroke, and in the other the spark occurs idle.
This type may have more than one type of connection to the spark plugs. Thus, this can happen using drives characterized by high voltage levels. And another method is explained this way: when one candle is directly connected through the tip, and the other is connected using the previously mentioned high-voltage wire.
Remarkably, a pair of dual coils can form a unique single mechanism. At the same time, it will have a new name - four-pin, which is hardly worth explaining. 
- An electronic direct-type ignition system is quite satisfied with an individual coil. Installation of this type is carried out in conjunction with the ignition, whose operation is exclusively electronic control, and the obligatory condition is the absence of any mechanical parts. Ignition in such a coil is carried out using a discharge coming from a capacitor, which is why this system is called direct. The basic functional part of an individual coil consists of turns made of copper wires in order to receive the primary voltage and convert the secondary circuit. It follows from this that a mechanism of this type includes two windings - primary and secondary, with the first located inside the second. The design of the primary winding is characterized by the presence of an internal core, and around the secondary there is an external core.
A custom coil type can house igniter components such as electronic ones. When high voltage is generated in the secondary winding, it is directly applied to the spark plug (this is done using a tip consisting of a high voltage rod, an insulating sheath and a spring). And in order for the high-voltage current in the secondary winding to be cut off as quickly as possible, a diode is installed there, which is also characterized by a high voltage level.
- All three previously named ignition systems can use a common coil. In this case, a mandatory condition for an electronic type system is the presence of a distributor unit.
Like the previously described individual type, this one combines the primary and secondary windings. 
The first consists of no less than one hundred turns of thick wire made of copper, which, in order to be able to prevent sudden surges in voltage along with a short circuit, was insulated. Also, the primary winding has two low-voltage characteristics terminals, which are located on the coil cover.
As for the secondary winding, it contains a much larger number of turns (the limit is indicated by the number 30,000), also of copper, but thinner wire. It is noteworthy that in general the secondary winding is located inside the primary, in contrast to the individual winding.
The main characteristic of all analyzed types is the resistance of the windings, which varies depending on the model of the mechanism. If the value deviates from the optimal value, this indicates a malfunction of the coil. 
It should also be mentioned that the windings, in order to be able to increase the strength of the magnetic field, are placed around a core made of iron. And all together this forms a structure that is placed in a housing with an insulating lid. In this case, the coil must be filled with transformer oil - this should prevent current heating.
How does it work
The principle of operation of the ignition coil is based on the basic physical laws that were taught in school. It can be characterized as follows: a low-voltage type voltage is sent to the primary winding. All this creates a magnetic field. Sometimes this voltage can be cut off by a breaker, which causes a sharp reduction in the magnetic field along with the formation of an electromotive force in the turns of the coil. 
If you believe the physical law regarding electromagnetic induction, then the magnitude of the electromotive force that arises in this way is proportional to the number of turns in the circuit winding. This can explain the fact that a high voltage pulse is formed in the secondary coil, because there are a large number of turns there. This impulse is sent to the spark plug. Moreover, this process is not typical for the individual type, since this type is installed directly on the candle.
It is thanks to this impulse, transmitted by a coil, that a spark occurs between the electrodes of the spark plug, which causes the fuel-air mixture to ignite. And at the moment when the occurrence of this spark is simply necessary, the contacts in the distributor-breaker open. At the same moment, the primary winding circuit breaks. A high-voltage current appears at the central contact of the coil, after which it is sent again - to the contact opposite which the slider electrode is located at that particular moment. After all this, the circuit is closed, and the impulse passes to the spark plug belonging to one of the cylinders. 
A small recommendation: the coil does not particularly welcome long-term loads, so it is better to turn on the ignition for a long time when the engine does not start. This is a proven fact, the implementation of which will help to maximize the duration of the described mechanism.
Outdated car models had such coils, the voltage from which was supplied to all spark plugs at once using an ignition distributor. The latter mechanism turned out to be not reliable enough, and therefore in modern cars they began to actively use systems with individual coils belonging to each individual spark plug. In this regard, the sparking energy increased, and the level of radio interference created by the ignition system, on the contrary, decreased. Also, the use of this system made it possible to say goodbye to the need to use high-voltage wires, which often turn out to be unreliable.
The coil, as the most important element of the overall ignition system, needs special attention and care. Therefore, this should not be neglected and should be expected until the last moment, until only this mechanism fails, but also the entire ignition system, and later the car. So I recommend that you always find time to carry out at least basic diagnostics of the car and the ignition system in particular, especially if the principle of its operation is now known. And may the car never fail.
Video “Removing the ignition coil”
After watching the video, you will learn how to remove the ignition coil yourself.
Output stages with individual ignition coils for each spark plug are widely used. In the combined unit, power transistors can be installed on the coils. This is done in order to unload the controller from many output stages.
Rice. Spark plug-ignition coil unit:
1 – bushing of the fastening bolt; 2 – output stage radiator; 3 – electronic unit; 4 – ignition coil core; 5 – primary winding; 6 – closing magnetic circuit; 7 – damping washer; 8 – noise suppression resistor; 9 – silicone insulator; 10 – secondary winding
An example of an ignition system with spark plug-coil units is the BOSCH ignition system integrated into the electronic engine automatic control system (ECAS), which is known as Motronic.
As an example, we can cite the functional diagram of the ESAU Motronic M-3.2, which is installed on four-cylinder engines of AUDI-A4 cars produced after 1995.
Rice. Static ignition system Motronik M-3.2 AUDI-A4 with individual coil for each cylinder:
DN – load sensor (throttle valve potentiometer); DH – ignition timing sensor (Hall sensor); DO – rotation speed sensor (magnetoelectric sensor on the crankshaft); DT – engine temperature sensor (thermistor); DD – piezoelectric knock sensor; S – ignition signal, alternately supplied to the inputs of the switch; A, B – connector contacts; VT – power transistors of the switch; N – inductive storage devices; TZ – ignition coils; SV - spark plugs.
The J220 controller has a microprocessor with a memory unit in which the three-dimensional ignition characteristic is stored. Using this characteristic, as well as the signals from the DO sensor G-28 (engine speed sensor) and the DN sensor G 69 (engine load sensor), the initial ignition timing is set. Next, based on the signals from the sensors DH G-40, DT G-62 and DD G-66, the digital microprocessor calculates the current (necessary for this mode of operation of the internal combustion engine) value of the ignition timing angle, which is supplied in the form of the main pulse S using an electronic channel switching circuit ignition into the corresponding channel of the electronic switch K-122. By this time, inductive storage N in this channel is in a charged state (from the on-board +12 V network) and, according to the signal S, is discharged to the appropriate level. After 180° rotation of the crankshaft, the described processes will take place in the next (in the order of engine operation) channel of the commutator.
The main advantages of the Motronic ignition system are as follows:
- individual static distribution of high voltage across spark plugs
- ignition coils with grounded secondary winding
- all input sensors (crankshaft speed sensor, internal combustion engine temperature sensor, throttle sensors, knock sensor) are generators of electrical signals from non-electrical influences of a non-contact operating principle. The analog signals from these sensors are converted into digital signals in the controller
- selective correction of the ignition timing for detonation (in each cylinder separately)
- shutdown of internal combustion engine cylinders in case of interruptions in spark generation (protection of expensive engine components - oxygen sensor and catalytic converter from damage
- Availability of self-diagnosis and backup functions in the controller
The ignition coil is one of the main elements in the control system of gasoline engines. Its failure leads to a lack of ignition in one or more cylinders. Therefore, every car owner should know the main signs of an ignition coil malfunction and the symptoms that precede the occurrence of this situation.
The device is the most conservative part in a gasoline internal combustion engine. Its prototype was invented in Germany by the engineer Ruhmkorff in the mid-nineteenth century. It replaced magnetos in automobile engines in the early 20th century.
Main purpose of the device– conversion of low-voltage electrical pulses with an amplitude of about 12 Volts (vehicle on-board voltage) into high-voltage pulses with an amplitude of more than 15,000 Volts. High voltage is necessary to break down the working area of the spark plug.
According to the type of design and ignition circuit, the coils are classified:
- single;
- double (triple, four-block);
- individual.
Single devices are used in systems with an ignition distributor. Twins are used in four-cylinder internal combustion engines without a distributor. One part forms a high-voltage pulse to the 1st and 4th cylinders, the second serves the 2nd and 3rd. Triple and quad coils are sometimes used in six-cylinder and eight-cylinder engines, respectively. Individual coils are widely used in modern cars. They are installed on each spark plug individually. A custom spark plug coil has a number of advantages over conventional ones:
- failure of one of the devices does not lead to a complete stop of the engine;
- it is easier to organize an electronic control scheme;
- the absence of a mechanical ignition distributor makes the system more reliable;
- distribution of pulse load reduces currents and increases service life;
- it is easier to identify a faulty device, which is easily done by computer diagnostics;
- Most individual coils have a pulse amplifier installed; it is controlled by low signal currents, which reduces electrical interference and increases the reliability of electrical equipment.
By type of control they are divided into:
- contact;
- electronic;
- with built-in switch (pulse amplifier).
In the ignition contact bobbins, a low-voltage pulse is generated by a chopper. When the primary circuit is switched by a breaker, an electromotive force pulse is induced in the primary circuit. The device is an autotransformer that increases the pulse amplitude N times, where N is the transformation coefficient equal to the ratio of the number of turns in the secondary to the primary winding. The transformation ratio of contact devices exceeds 1000.
Contactless systems use electronic coils. Their transformation ratio is higher and they form a stable spark. During repairs, contact and non-contact devices cannot be interchanged.
A built-in switch is installed on most individual coils, often installed on dual coils. Their disadvantage is a higher probability of failure due to the presence of electronic components.
Symptoms of malfunction
More often than not, the bobbin does not suddenly fail. This is usually preceded by a number of warning symptoms.
The main symptoms of a faulty ignition coil:
- misfires in one or more cylinders, they can be determined using a scanner by the presence of the “triple” effect of the engine;
- the appearance of “breakdown tracks” on the housing can be determined visually when starting the engine in the dark;
- the occurrence of cracks and chips in the dielectric zone;
- overheating of the structure;
- burning of rubber tips of high-voltage wires;
- oiling, contamination.
If the above symptoms appear, you should consider purchasing a replacement device. You can't stand by and watch an ignition coil die. In the event of a sudden coil failure, further independent movement will be impossible (unless you have individual coils installed).
Causes of ignition coil failure
Let's look at the reasons why the ignition coil fails.
Natural wear and tear
Like all electrical and electronic units, the reel has a certain trouble-free operation life. The average service life of ignition coils is approximately seven to ten years of operation or 150,000 - 200,000 thousand mileage. The device is operated in extreme conditions with large differences in temperature, humidity, and the possibility of ingress of moisture, dirt, and foreign liquids. In this case, large currents flow through the primary winding, and a high-voltage pulse is formed in the secondary winding.
Electrical breakdown
Let's figure out why the ignition coil breaks. Firstly, over time, as a result of high temperature changes, the dielectric insulation cracks, and salty moisture, which is a conductor, can enter microcracks. For voltages of more than 15,000 volts generated in the secondary winding, even pure undistilled water acts as a conductor. Secondly, during operation, the physical properties of the dielectric and rubber insulation of the tips of high-voltage wires, especially those of dubious production, change. High-voltage breakdown can be caused by the installation of non-standard high-voltage wires in which there is no distributed current-limiting resistance. A breakdown can occur as a result of severe contamination or waterlogging. Even in the event of a single breakdown, irreversible changes occur in the structure; further operation is not recommended.
Overheat
Some vehicles have ignition coils installed directly at or near the top of the engine. If there is no air access to their structure for natural ventilation (this is possible when installing additional equipment), the device may overheat and fail.
The coil mount must be standard. Some car enthusiasts neglect these requirements by “hanging” it on homemade structures.
Wear of spark plugs, high-voltage conductors
Despite the fact that the circuit has a limiting resistance, wear of spark plugs and high-voltage conductors can cause electrical breakdown in them. Then the load current increases and the bobbin may overheat.
Generator voltage regulator relay malfunction
Sometimes it leads to an increase in the voltage of the vehicle’s on-board network and failure of the electronic amplifier (switch).
Malfunction of the contact group of the lock, electronic switch
If, during parking, +12 Volts are constantly supplied to the coil in the event of an abnormal closure of the lock contact group, the device may overheat and fail. The same situation is possible if the switch is faulty.
To prevent premature failure, all possible causes of malfunction of the ignition coil in the car should be eliminated as much as possible.
Symptoms of a problem
The main signs of ignition coil failure are lack of ignition. If it is a single device with a distributor, then in all cylinders; if it is a double or single device, then in those served by it. The absence of a spark is not necessarily a 100% sign of a faulty coil. Perhaps the limiting resistor has burned out, the spark plug is faulty, the high-voltage wire has broken, or there is a malfunction in the ignition system. A comprehensive fault diagnosis is required.
Visual signs that the ignition coil is not working:
- the presence of “breakdown tracks”, oxides on the coil;
- change in dielectric color;
- burning of contacts and connectors;
- traces of overheating on the body;
- increased pollution.
How to identify a faulty ignition coil
The procedure for checking the serviceability of the coil depends on how many ignition coils are in the car. If your car has individual ignition coils, in order to identify the faulty one with a high degree of probability, you can swap the supposedly faulty and known-good coils. If, as a result of this replacement, a spark appears in the cylinder in which there was no spark, and disappears in the other, therefore, the bobbin is truly faulty. In the same way, you can check dual and block coils, but you will have to modify the circuit, which is not always convenient.
How to determine which ignition coil is not working without making changes to the electrical circuit
To do this, you need to stock up on thick dielectric gloves and a dry rubber mat. The use of only ordinary dielectric gloves is unacceptable: they can withstand a breakdown voltage of 6300 Volts; the voltage applied to the candle is approximately three times higher.
If your car has two or more ignition coils, if one of them malfunctions, the car should start, but struggle a lot. By removing the tips of the high-voltage wires of the spark plugs or connectors from individual coils one by one, the stability of the engine is assessed. If the internal combustion engine has not changed its operation as a result of removing the connector, then there is no spark in this cylinder. If the engine starts to shake even more, or stalls altogether, there is a spark, the bobbin is faulty, or it is not receiving impulses or power.
Multimeter
If the car engine does not start at all and does not catch, you can evaluate the serviceability of the coil using the parametric method. For this you will need a multimeter. An ordinary coil like the Zhiguli one can be ringed without difficulty. To do this, first set the multimeter’s measurement limit to the resistance measurement mode of 200 Ohms or “diode, continuity” and measure the resistance between the coil terminals + and K. The resistance should be in the range from 0.2 to 1.0 Ohms. Please note that during measurement at this limit a small error may appear, which will slightly increase the multimeter readings. Then switch the multimeter mode to the limit of 20 kOhm and measure the resistance value of the second winding (between terminal K and the copper tip into which the high-voltage wire is inserted). The resistance should be in the range of 1 kilo ohm to 3 kilo ohms (2000 - 3000 ohms).
It is impossible to check a coil with a built-in pulse amplifier using this method, since the lead of the primary winding is not connected to its terminals. A common malfunction of individual devices is breakdown of the limiting resistor. It is located under the rubber extension of the reel structure, which is easily removed. The resistor should be removed and its resistance measured with a multimeter at a limit of 20 kilo-ohms. It should be between 1 and 3 kilo-ohms.
Megaohmmeter
You can also evaluate the insulation resistance if you have a megohmmeter at your disposal. The insulation resistance (between the copper contact into which the high-voltage spark plug wire is inserted and the housing) must be more than 300 megaohms. This measurement is of an evaluative nature. If the resistance is less, the coil is probably faulty, if the resistance is more, it is probably working, it is impossible to judge more precisely.
A simple three-terminal coil can be checked “by weight”, that is, by assembling a simple circuit. The +12V voltage from the battery is connected to the + terminal, a high-voltage wire is inserted into the connector, and a spark plug is connected to the second terminal. The spark plug body is connected to the metal part of the engine. Next, connect a stranded insulated conductor with a cross-section of 2 sq. mm to contact K. Holding the insulation, briefly touch the metal part of the engine with the other stripped end of the wire. A spark should jump where the engine touches and through the spark plug. In electronic coils, the spark from the spark plug is less intense. You cannot experiment with this method for a long time.
Some specialized service stations have self-made inspection stands. Their use requires special methods.
In order for the coil to work longer, follow the rules:
- install the device on standard mounts;
- do not clutter the device area, ensuring good ventilation;
- keep the body clean;
- check spark plugs and high-voltage wires in a timely manner (before the start of each operating season).
The ignition coil is the second element in the sequence of the car engine ignition system. The operation of the ignition coil is similar to the functions of a transformer and is based on the conversion of low voltage voltage from the vehicle's rechargeable (starter) battery into high voltage voltage generated for the spark plugs, resulting in ignition of the air-fuel mixture.
The coil consists of primary and secondary windings, an iron core and an insulated housing. On a core made of thin metal plates, two windings of thick and thin copper wire are wound.
The principle of operation of the ignition coil is similar to that of a transformer. When voltage is applied to the primary winding circuit, a magnetic field is created in the coil. The secondary winding of the ignition coil is self-inducing and generates voltage. The transformed voltage is supplied to the spark plugs through a switchgear, and the high-voltage discharge continues until the energy created by the coil is spent.
Types of coils
Today, there are a sufficient number of types of ignition coils that can be installed both on old domestic cars with carburetor engines and on more modern cars with direct fuel injection.
Housing ignition coils are installed on vehicles with mechanical ignition distribution, where the distributor, rotating, supplies high-voltage voltage to each spark plug in a certain sequence. This method of switching and voltage distribution is not used in the modern automotive industry due to its short service life and low reliability.
A coil with electronic ignition distribution, or a distribution coil, does not require an additional contact cascade breaker for its operation, because with the development of technology in microelectronics, it has become possible to integrate such an ignition breaker into the coil itself. This coil is suitable for cars with mechanical ignition distribution.
A dual-spark ignition coil allows spark plug voltage to be generated simultaneously in two engine cylinders per crankshaft revolution, without the need for coordination between the ignition system and the camshaft. It is advisable to use such coils only in engines with an even number of cylinders, for example, for an engine with four cylinders you will need two coils, with six - three, respectively, with eight - four.
The "smart" plug ignition coil is single-spark and is installed directly on each spark plug. The design and functional characteristics of such a coil make it possible to avoid the use of high-voltage wires in the system, but it requires connecting clamps (terminals) designed for high voltage. Due to their compactness, these coils are used in cars with a small amount of free engine compartment space, but compact does not mean ineffective. The plug coil can easily compete with its brothers.
The advantages of the reel are:
- The widest range of ignition timing settings.
- Diagnosis of misfires from the primary and secondary windings.
- Spark extinguishing in the secondary circuit using a high voltage diode.
Such devices are used for engines with any number of cylinders, but synchronization with the position of the camshaft using an appropriate sensor is strictly required.
Coil malfunctions and their diagnosis
The ignition coil is a fairly reliable element of the system, but it is not immune to all sorts of malfunctions, often associated with non-compliance with operating rules. Let's look at the most common signs of a faulty ignition coil:
- Unstable engine speed at idle.
- Engine stalls when the throttle valve is opened sharply.
- The "Check" light came on.
- No spark.
First of all, if a breakdown occurs in the ignition system, you should visually inspect the coil and look for cracks, charring, and also check its temperature and humidity. If the ignition coil heats up, this may indicate that an interturn short circuit has occurred and the device must be replaced. High humidity in the area where the ignition coil is located can also affect engine performance. If the coil is dry, without cracks, soot and not hot, but there is still a malfunction in the system, it is necessary to diagnose it.
If the car does not start, that is, the starter cranks, but the engine does not pick up the ignition, this may mean that there is no spark from the ignition coil.
- How to check the ignition coil for functionality for a contactless ignition distribution system? It is necessary to disconnect the high-voltage wire located in the center of the ignition distributor and position this wire at a distance of approximately 5 millimeters from the metal body of the engine. Then we turn the engine crankshaft with the starter and observe the presence of a spark in the gap between the contact part of the high-voltage wire, which was disconnected from the distributor, and the engine housing (ground).
- In a contact ignition system, cranking of the crankshaft by the starter is excluded from this procedure, namely: remove the ignition distributor cap and set the voltage breaker contacts to the closed state. Then we turn on the ignition with the breaker lever, open and close the contacts. The presence of a spark in the gap between the wire and ground tells us that the ignition coil is working properly.
If the ignition coil diagnostics reveal a lack of spark, then you need to check the resistance of the ignition coil. To do this, you will need a regular multimeter or ohmmeter and a technical passport for the coil, where you can see its parameters, including the resistance of the windings. Before checking the ignition coil, disconnect all the wires and measure the resistance of both windings one by one, while the resistance of the primary winding should be less than that of the secondary. If during the measurements it turned out that the resistance of both windings corresponds to the factory parameters, and when checking “for a spark” there was no spark, then we can conclude that an insulation breakdown between the turns and the housing has occurred.
Replacing the ignition coil
If the coil malfunctions and cannot be restored, it must be replaced. You can buy exactly the same original one, or you can choose a similar one, but their characteristics should not differ by more than 20-30 percent, and also have the same fastening and design. For example, for domestic cars VAZ-2108 - 2109 with electronic coils 27.3705 from a domestic manufacturer, coils 0.221.122.022 from Bosch, which are not much different in parameters, are suitable. In this case, the spread of parameters will be from 10 to 15%.
To summarize, it can be noted that when writing the article, real information was used about the problems that each driver faced. All coils are practically the same from each other in terms of their operating principle, but not all of them are interchangeable, for example, coils with mechanical ignition distribution cannot work with contactless distribution and vice versa.
If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them