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Ignition System Coil

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An ignition system is a system for igniting a fuel-air mixture. It is best known in the field of internal combustion engines

The ignition coil is a basic component - It is a high-voltage transformer consisting of two coils of wire. One coil of wire is named the primary coil. Wrapped around it is the secondary coil. The secondary coil usually contains hundreds of times more turns of wire than the primary coil.

Typical Ignition System (DIS) Distributorless Ignition System Spark Plugs Coil Distributor Testing with a Multi-meter

Typical Ignition Induction Coil : Transforms a battery's 12 volts into the thousands of volts needed to spark the spark plugs.

In older vehicles a single (large) coil would serve all the spark plugs via the ignition distributor. The large wire, known as the coil wire provided the ignition spark to the distributor. To test the ignition coil follow the procedure below.

Connect the ohmmeter to the primary studs of the coil. Turn the meter to the 0-2M ohm scale. Compare your reading to the primary winding specification for the coil. (Figure 1)
Remove either one of the meter leads from the primary stud and connect it to the coil wire lead. Reset your ohmmeter to the 2M-20M ohm scale and compare the reading to the secondary winding specification for the coil. (Figure 2)
If the primary or secondary winding readings do not fall within the range indicated in the service manual, replace the coil.
If the coil tests within specifications, refer to the proper service manual for further diagnosis.

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