The basic unit that ensures that your car engine fires on all its cylinders is the ignition coil or the ignition coil pack. If this malfunctions to the smallest degree, the chances are you will have trouble starting your car. Not even jump starting will help. Hence, ignition coil testing is one way to diagnose ignition coil malfunctions.

What is an ignition coil?

The ignition coil is an electrical device, consists of two coils. One coil is the primary, comprising of thick copper wire of shorter length. The secondary coil comprises of a much greater length of thin copper wire. They are mounted on an iron core which provides the magnetic field for the generation of high voltage necessary to generate sparks at the spark plug for ignition to happen. Modern cars have two variants to the sparking system necessary for ignition.

  • The first has all coils mounted on a single pad. If any coil is defective the entire pack needs replacement.
  • The other has the ignition coils individually on a mounting pad. If any single coil is defective it can be replaced easily.

essentials DIY ignition coil testing


Ignition Coil Testing

There are two ways of ignition coil testing. The first is a simple visual test. The other is an accurate data driven test. Testing an ignition coil is not difficult. Just follow the tips below to be guided.

  • Unscrew the spark plug after removing the wire connected to the coil.
  • Reconnect the wire to the spark plug and hold the spark plug tip close to any metallic component in the engine compartment.
  •  Ask someone to start the engine while you hold the plug as mentioned above.
  • If the spark plug emit a sharp blue spark, the coil is fine. If the spark is dull or if there is no spark, the coil could be faulty.

A surer way of testing ignition coil is by using a multimeter. With this instrument, it is possible to methodically test both the primary and secondary coil. Here are the steps on how this is done.

  • Remove the ignition coil from the car.
  • Using your user manual, determine which of the terminals indicate poles for the primary coil.
  • Place the leads of the multimeter on these poles and read the multimeter results. The reading on the multimeter should be within the specified range in the user manual.
  • If the reading is outside the voltage range specified by the manual, the coil needs to be replaced.
  • The user manual will also indicate the relevant poles. Please note that these terminals carry a far higher voltage.

ignition coil testing and troubleshooting

Ignition coil pack testing is similar. All wires from the spark plugs lead to the ignition coil. Remove the pack from the car. The sequence of testing the pack is similar to the coils. The difference is there will be more than one coil on the pack and you will need to test each of the coils individually. Keeping the ignition coil or the ignition pack tested is very important. Ignition coil testing will ensure efficient starting of your vehicle.