What is the measurement method for the ignition coil?
2 Answers
The measurement method for the ignition coil is as follows: 1. Turn on the ignition switch, confirm that the low-voltage circuit is normal, then pull out the high-voltage wire from the center of the distributor cap, keeping it 3-5mm away from the cylinder block. 2. Use a screwdriver to toggle the breaker points. If a blue-white spark jumps between the high-voltage wire and the cylinder block with a crisp sound, it indicates that the ignition coil is in good condition. If there is no spark and the high-voltage wire is confirmed to be normal, it means the ignition coil has failed. 3. During engine operation, the condition of the ignition coil can also be judged by temperature. A slightly warm coil is good, while a scalding hot one is faulty or damaged. 4. Install the suspected ignition coil on a gasoline engine with a fully functional ignition system for a spark test to determine its condition.
Measuring ignition coils is actually quite simple, and I often tinker with them in the garage. First, you need to prepare a multimeter and set it to the resistance mode. After turning off the engine, unplug the ignition coil connector. To measure the primary resistance: between the two terminals, the value should typically be between 1 to 2 ohms. If the value is too high or infinite, the coil may have an internal open circuit. For the secondary resistance test: place one probe of the multimeter into the high-voltage output hole and the other probe to ground or the primary terminal. The reading should be within the range of 5000 to 15000 ohms. If it's too low or zero, it indicates a short circuit. Safety is crucial—ensure the battery is disconnected before testing to avoid electric shock. Ignition coil issues often cause engine misfires, so testing and replacing them early can save fuel costs and prevent spark plug damage. After reassembly, remember to start the engine and check the results. Don’t overlook the manual’s specified normal values, as they may vary slightly between different vehicle models.
