How to Test an Automotive Ignition Coil?
2 Answers
Testing methods for ignition coils include: 1. When testing an ignition coil, the primary method involves using a multimeter to measure the resistance values of the primary and secondary windings. 2. The performance of an ignition coil can be tested on a universal test bench, mainly by measuring the spark gap to determine its performance. Additional information: 1. An ignition coil is a transformer that generates the high voltage required for ignition, converting 12V low voltage into 15–20kV high voltage. 2. However, the working principle of an ignition coil differs from that of a regular transformer. While a regular transformer operates continuously, an ignition coil works intermittently, storing and releasing energy at varying frequencies depending on the engine's speed.
When I previously repaired my car and tested the ignition coil, the method was quite simple. First, turn off the engine and disconnect the battery to ensure safety. Visually inspect the coil casing for cracks, burns, or oil stains, as these signs indicate problems. If you have a multimeter, measure the primary coil resistance, which is usually between 0.5 and 2 ohms, and the secondary coil resistance, which is around 5k to 15k ohms. Check the vehicle manual for specific values. If you don't have tools, perform a spark test: disconnect one spark plug wire, connect an old spark plug to ground, start the engine, and observe the spark color. A strong blue spark is normal, while a red or no spark indicates a faulty coil. If the ignition coil is bad, the car will shake, have difficulty starting, or experience increased fuel consumption. Last time I tested, I found abnormal resistance, and replacing the coil fixed the issue. Regular maintenance checks can prevent major problems, saving money and providing peace of mind. If you can't handle it yourself, don't force it—seek professional help.
