How to Measure the Condition of an Ignition Coil?
2 Answers
Checking whether the ignition coil is in good condition can be performed on the engine. Here is more information about inspecting the ignition coil: 1. Method: Turn on the ignition switch, and after confirming the low-voltage circuit is normal, if there is a blue-white spark jumping accompanied by a crisp sound, the ignition coil is functioning well. If there is no spark and the high-voltage circuit is confirmed to be normal, it indicates the ignition coil has failed. 2. Fault symptoms and diagnosis: Damage due to external force or burnout from excessive current. If the ignition coil is damaged, the ignition system will fail to operate, and the engine will not start.
To measure the condition of an ignition coil, my method is to first use a multimeter to test the resistance values. Find the ignition coil in a car, disconnect the wiring, set the multimeter to the resistance mode, and touch the primary terminals with the probes. The normal reading should be between 0.5 and 2 ohms. If the reading is infinite, it means the coil has an open circuit. Next, measure the secondary terminals, which typically range from 8k to 15k ohms—readings too low or too high indicate a problem. I also like to perform a spark test: remove the spark plug, place it against the engine's metal part, start the engine, and observe the spark color—a blue-white spark is healthy, while a weak or absent spark means the coil is faulty. Don’t forget to inspect the exterior for cracks or burn marks, as these are also signs of failure. If unsure after testing, try replacing it with a new one—if the engine starts smoothly, you’ll know the condition. Always wear gloves during the process to avoid electric shock, and it’s best to perform the test when the engine is cold. Remember, the ignition coil affects engine efficiency—frequent failures can lead to poor performance and increased fuel consumption, so early detection saves major trouble.
