Do You Need to Replace All Four Ignition Coils If One Is Bad?
2 Answers
Ignition coils need to be replaced all four if one is bad. The ignition coil is a device that provides ignition energy. The reasons for ignition coil failure include: 1. Excessive gap between spark plug electrodes; 2. Engine overheating; 3. Open circuit in the high-voltage wire; 4. Thermal effect caused by current; 5. Poor fuel quality; 6. Incorrect cylinder compression ratio; 7. Program failure in the ECU. The functions of the ignition coil are: 1. When the primary coil is connected to the power source, a strong magnetic field is generated around it as the current increases, and the iron core stores magnetic field energy; 2. When the switching device disconnects the primary coil circuit, the magnetic field of the primary coil rapidly decays, and the secondary coil induces a higher voltage; 3. The faster the magnetic field of the primary coil disappears, the larger the current at the moment of disconnection, and the greater the turns ratio between the two coils, the higher the voltage induced in the secondary coil.
I remember last time one of my car's ignition coils went bad, I just replaced that single one and the problem was solved—no need to replace all four unless the car is very old or shows frequent signs of failure. The ignition coil is a small component that delivers electricity to the spark plug; when one fails, it can cause engine shaking, increased fuel consumption, and a sluggish driving feel. Pay attention to the engine's performance during daily driving—if it suddenly vibrates during acceleration or uphill climbs, that could be a warning sign. Checking the condition of the other coils is crucial; I usually use a diagnostic tool to measure their resistance values—if they're normal, you can save some money. Don’t slack on maintenance—inspect them every two years or 30,000 kilometers to extend part lifespan and avoid trouble. While replacing all four offers stronger preventive measures, it doubles the cost, so weigh your actual needs carefully. The key is to fix it promptly; otherwise, it might lead to more parts failing.
