If your car’s engine is running rough, it could be time for a tune-up. Part of a tune-up includes testing the ignition coil with a multimeter. This quick and easy test can save you time and money by diagnosing the problem early on.
An ignition coil is an induction coil in an engine’s ignition system that transforms the battery’s low voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel.
What is an ignition coil?
An ignition coil is an inductive coil that is part of an automobile’s ignition system. It amplifies the low voltage signal from the ignition switch to the spark plugs.
How does an ignition coil work?
An ignition coil is a type of transformer that steps up the voltage of the low-voltage current from the battery to the high-voltage current needed by the spark plugs. The coil consists of two sets of windings, primary and secondary, wrapped around an iron core. When the engine is cranked, a charge voltage from the battery flows through the primary windings and sets up a magnetic field in the iron core. When the engine is fired, a contact breaker points open and interrupts this current flow. This sudden break in current flow induces a high voltage in the secondary winding, which is then transmitted to the spark plugs to ignite the air-fuel mixture in each cylinder.
What is a multimeter?
A multimeter is a device that measures multiple electrical properties of a circuit. The most common properties that are measured are voltage, current, and resistance. Multimeters can be either analog or digital. Analog multimeters have a needle that moves along a scale to indicate the value of the property being measured, while digital multimeters have a digital display that shows the value.
How to test an ignition coil with a multimeter
Using a multimeter to test an ignition coil is not as difficult as it might seem at first. In order to test an ignition coil, you will need a few tools and supplies, including a multimeter, an automotive spark plug, and some basic knowledge of how ignition coils work.
Before you begin, make sure that your multimeter is properly calibrated and that you have fresh batteries in it. Once you have everything you need, follow these steps to test your ignition coil:
1. Check for spark. Before you do anything else, make sure that there is no spark coming from the ignition coil. If there is spark, it means that the coil is working and you don’t need to do anything further.
2. Test the primary winding. To do this, disconnect the negative (-) lead from the battery and connect it to the ground (GND) terminal on the multimeter. Then, touch the positive (+) lead of the multimeter to the positive (+) terminal on the coil. You should see a reading of between 0.5 and 2 ohms on the multimeter if the primary winding is healthy.
3. Test the secondary winding. To test the secondary winding, disconnect the negative (-) lead from the ground (GND) terminal on the multimeter and connect it to one of the terminals on the coil (it doesn’t matter which one). Then touch the positive (+) lead of the multimeter to the other terminal on ˆthe coil. You should see a reading of between 5,000 and 30,000 ohms if ˆthe secondary winding is healthy.
4. Repeat steps 2 and 3 for each additional Ignition Coil in your vehicle until all have been tested
Tips for testing ignition coils
Testing ignition coils is a fairly straightforward process that can be done with a few tools. You will need a multimeter, an inductive timing light, and a helper. With the right tools and a little know-how, you can test ignition coils and ensure they are working properly.
Here are some tips for testing ignition coils:
-Multimeters can be used to test for continuity, resistance, and inductance. To test for continuity, connect the multimeter leads to the coil terminals and set the meter to the Ohms function. A reading of zero ohms indicates continuity. To test for resistance, connect the multimeter leads to the coil terminals and set the meter to the Ohms function. A reading of infinite ohms indicates an open circuit. To test for inductance, connect the multimeter leads to the coil terminals and set the meter to the Inductance function. A reading of zero ohms indicates an inductor coil.
-An inductive timing light can be used to test for spark by hooking it up to the coil primary lead and pointing it at the spark plugs while cranking the engine over. If there is spark, the timing light will flash.
-A helper can be used to observe the engine while you are testing it. This will allow you to see if there are any unusual sounds or movements that could indicate a problem with the ignition system.
Common ignition coil problems
Common ignition coil problems include failure to produce spark, failure to produce enough spark, spark that is too weak, spark that is too strong, or spark that is intermittent. Ignition coils can also develop faults such as short circuits or open circuits.
Now that you’ve tested your multimeter on the primary and secondary winding of the ignition coil, it’s time to put it all together. Check the resistance of the primary winding again. If it’s still within specification, then the ignition coil is fine. If not, then it needs to be replaced.