How To Check The Ignition Coil?

The ignition coil operates in electronic, contact and contactless ignition systems. It is a two-winding transformer. To date, there are several types of ignition coils: dual ignition coil, standard, as well as an individual. The standard coil uses in contact and contactless systems. And also, in electronic with the distributor.

If you have any problems with the engine, and the reason for this is the coil, before checking the ignition coil, familiarize yourself with its design as follows.

Ignition Coil Arrangement.

The ignition coil has the following layout. It combines two windings. the primary and the secondary. The first one contains from one hundred to one hundred fifty turns of thick copper wire. The wire is insulated to avoid short circuits and power surges. The primary winding has a pair of low-voltage leads on the cover of the coil itself.

The secondary winding contains from fifteen to thirty thousand turns of thin copper wire. This winding locates inside of the primary. One end of the secondary winding connects with the negative terminal of the primary winding. The other one compares with the central terminal located on the cover. Such a terminal provides a high voltage output.

The windings are located around the iron core to increase the strength of the magnetic field. Together with him, they place in a housing that has an insulating cover. The coil is filled with transformer oil to prevent current heating.

Now, knowing the device coil, you can figure out how to check the ignition coil. To do this, we need to study its characteristics in order not to harm the device with our test.


The main characteristics of the coil. winding resistance, which is individual for each model. For example, the resistance of the secondary winding is about five to nine thousand ohms. And the primary resistance is 3-3.5 ohms. If there is a deviation of the resistance value of the winding from the accepted value, this may indicate a malfunction of the ignition coil.

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Coil operation is based on the occurrence of high voltage in the secondary winding, in the process of passing a current pulse with a low voltage across the primary winding. When current passes through the primary winding, forms a magnetic field. It induces a high voltage current in the secondary winding, which is output through the central terminal of the ignition coil. And then, with the help of the distributor, the current is fed to the spark plugs.

Individual coil.

The electronic direct ignition system uses an individual coil. As well as in general, it includes primary and secondary windings. Only in this case, on the contrary, the primary is inside the secondary winding. The outer core locates around the secondary core, and the inner core installs in the primary core.

It should also be noted that some electronic components of the igniter may be present in the individual coil. With the help of a tip, which includes a spring, a high voltage rod and an insulating sheath, high voltage, which produces in the secondary winding, is fed directly to the spark plug. In the secondary winding, it is customary to install a high voltage diode. It is done to cut off the high voltage current quickly.

The double lead ignition coil widely uses in many electronic direct ignition systems. Such a coil has a pair of high-voltage leads, which ensure simultaneous reception of a spark simultaneously by two cylinders. And only one cylinder at this moment is located at the end of the compression stroke. In the second cylinder, the flash is idle, at the exhaust stroke.

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A twin coil can be connected to spark plugs in different ways. The first type of connection. using high voltage wires. The second. in which one candle. with the help of high-voltage wires, and the second. directly through the tip.

Coil health check.

If, for some reason, you think that the coil is malfunctioning, see how to check the serviceability of the ignition coil and what it takes.

First, you need to inspect the ignition coil carefully. Then we check its surface for contamination, leading to the departure of stress on the mass. Then we need to examine the body of this coil carefully. If oil spots are visible on its surface, this is a sign that there is dirt on the cover. And the presence of dust can lead to complete malfunction of the part. Next, you need to check the findings of the wires. They must be free from rust or oxidation.

If there is a contact ignition system, the condition of the coil can check by installing the high voltage central wire at a distance of about 5-7 mm from the body of your car. If at the time of contact opening a blue spark is formed, it means that the ignition coil is operational. If this part breaks, the flash will be either weak or absent altogether.

Next, we need to measure the resistance of the windings, as well as the insulation of the coil. It should correspond to the values, specified for your type of car. Therefore, before checking the serviceability of the ignition coil, read the values ​​for your car (if any). If you do not have such data, then the resistance of the primary winding should be about five ohms, in the case when the voltage on it is equal to twelve volts. And the insulation resistance should be approximately 50 mΩ.

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Polarity check.

Now you need to check the polarity of the wires and the insulation of the ignition coil. If their location is confused, you need to fix it. We measure the current in the circuit, thereby checking the primary winding with an ammeter. Next, we turn on the ignition system and close the breaker contacts. Do not forget that in this case, the current should correspond to the data for your car. If the value obtained exceeds this value, it means that the winding is broken.

How to check the ignition coil, so as not to cause its malfunction? When you install the coil in its place, you need to monitor so as not to confuse the wires carefully. Such confusion can cause damage and burning of the breaker contacts if at all, can lead to a short circuit.

You should also remember that in a contactless ignition system, it is impossible to operate a coil intended for use in a contact system. Such negligence entails a breakdown of the electronic sensor.

Before checking the serviceability of the ignition coil, consider that compliance with the rules of operation of the car and timely diagnosis will eliminate the need for such checks.

If you do not want to allow the enormous cost of repairing the engine and its parts, you need to pay attention to the first signs of a car engine malfunction, as well as its natural wear and tear. Only timely identification of faults and subsequent repair of the engine will help save significantly not only on the restoration itself, but also on spare parts, the cost of which often exceeds the amount of the repair itself.