Ignition coil: device and diagnostic methods
Purpose of the ignition coil
Ignition coil is one of the most important elements of ignition of fuel in engine cylinders. It is a device that consumes low-voltage current from a car battery and converts it into high-voltage pulses. At the right moment they form a spark between the spark plug electrodes and ignite the fuel-air mixture.
The device of the ignition coil is similar to a transformer: it also has two windings (primary and secondary) on the core, and a special device converts the battery's direct current into a pulse, the voltage of which increases several thousand times according to the law of electromagnetic induction. In the ignition systems of old cars there was only one such node. The pulses from it were alternately fed to all the candles through the distributor and high-voltage wires. But lately, on machines, a system with the removal of a separate coil on each cylinder is increasingly common.
Diagnostics by closing the spark plug to the body
Without this device, the car can not start. Therefore, checking the ignition coil is an operation that any motorist should be able to perform. The most common way is to unscrew the spark plugs from the cylinder and close them on the engine block with a subsequent attempt to start the car. If the spark slips between the electrodes, then the ignition coil is OK. If not, then, most likely, the problem is in this device. But many motorists there is an opinion that with this method of checking the ignition coil can disable.
Diagnostics by measuring resistance
There is a safe alternative, but in this case you will need an ohmmeter. The method consists in measuring the resistances of the windings. Their exact values are indicated in technical reference books, but usually the working ignition coil has a resistance of 16-17 kΩ on the primary winding. If a strong discrepancy with this figure or even a rupture (infinite resistance) or a short circuit (the value will tend to zero) is detected, then most likely this unit is faulty.
Alternative diagnostic methods
Another way is to install your coil to another machine. In this case, you will unambiguously find out whether the component is intact. The difficulty is that the car must be the same brand and the same configuration as yours, and you also need the consent of its owner. There are also visual signs of failure of the coil: the smell of burning insulation or traces of breakdown (the presence of black burned-out points on the case and windings).
Is it possible to repair the ignition coil
What should I do if a fault is detected in this component of the ignition system? Only change - the coil can not be repaired. More precisely, it can be repaired, but the complexity of replacing the windings makes such an operation unprofitable.
Method of work
Remember the safety precautions for all manipulations with the ignition system, since the coil voltage can reach 20-25 thousand volts. Use tools with electrically insulated handles and do not work in damp areas or in the rain. If you can not find the cause of a car malfunction on your own, contact a specialized service. Good luck on the roads!