Ignition Coil plays an important role in the vehicle ignition system. In such ignition systems, as contact, contactless and electronic, the coil creates a high voltage.
Despite the rather rare coil breakage, it still happens. The most common cause of failure of the ignition coil is an insulation fault, followed by its short circuit. Also, when malfunctioning spark igniter or high-voltage wires the electrical system overload or circuits break may occur.
In order to check the ignition coil properly, you need to understand several things.
After dismantling, before check the ignition coil using devices, it should be visually inspected and verified that there is no bringing on the side. To do this, make sure that there are no black burned spots or cracks on the coil body, which are the signs of the coil breakdown.
To test the coil, the method, which was quite right to exist: performance testing of the coil through the identification of sparks between the spark igniter and the car body, is not suitable. In modern cars, such experiments can lead not only to the failure of the coil, but the whole vehicle electronics. For the coil performance testing, they use a multimeter. In winding fuse, the multimeter tips the scales and shows a maximum value.
If there is a circuit of coil turns, the readings will be different from the factory specifications. It is necessary to clarify the readings using in the diagnosis. But you can also use the following figures:
- The secondary winding resistance should be in the range from 0.4 to 2 ohms. There are exceptions. For testing, the device is connected to the positive and negative coil contacts.
- The primary winding resistance can vary between 6-8 kilo ohms, but also there are exceptions, and resistance can be as high as 15,000 ohms. Please measure by connecting the positive coil contact with the high voltage output. In some coils, the contacts can be hidden in the connectors.
You also need to be aware of the fact that each coil has various indicators, such as:
- Winding resistance;
- Ignition duration;
- Ignition energy;
- Ignition current;
- Primary widing inductance.
Therefore, in order to understand if the testimony of the coil is OK, it is necessary to clarify the specifications of your individual coil. This is especially useful if you lost the spark, as ignition coil is one of the first system elements that are subject to check.