Ignition coil plays an irreplaceable role in the engine. So what are the symptoms if ignition coil has a fault? Can l drive when my car has a faulty ignition coil? How can I know ignition coil is faulty? A faulty ignition coil can lead my car to more fuel consumption and less power? We will discuss these questions in this article.

Fault analysis of ignition coil

The fault indicator light is on, and the fault code shows that there is a misfire. The car does shut off suddenly when driving, but it can start normally soon after flameout. The test result shows the resistance of the terminal connection between the ignition module and ignition coil was completely normal. However, in fact, the insulation layer inside ignition coil has been burned down. After the ignition coil reaches a certain working temperature, an internal short circuit will occur during thermal expansion, leading to misfire. The ignition system with distributor will suddenly shut off when the car is hot, while the ignition system without distributor will work unsteadily when the car is hot. Remove the fault code, replace the ignition coil and ignition module, and try again to see if there is still a fault code. If the ignition coil and ignition module are replaced with a new one, the fault code of misfire indicates that the original ignition coil or ignition module is indeed faulty.

As a core part in the ignition system, ignition coil undertakes the function of converting low-voltage current  into high-voltage current intermittently. If the engine does not have high voltage generated by ignition coil, then the combustible mixture in the cylinder will not be ignited, and the engine will not work normally.

What are the symptoms of ignition coil failure?

If the engine ignition coil is faulty, it will greatly affect the whole ignition system and the operation of engine.

Specific symptoms as follows: 

Engine wobble: Once ignition coil is faulty, as the spark plug cannot ignite combustible fuel-air mixture, it is very easy to cause the engine misfire, resulting in engine wobble. If the number of cylinders are faulty or if two adjacent cylinders are misfire at the same time, the engine will most likely fail to start normally.

Fuel consumption increases and power decreases: Even if the failure of ignition coil does not cause the engine misfire, combustion of air-fuel mixture in the engine chambers will still be affected due to the reduction of jump spark, thus causing adverse reactions such as fuel consumption increase and power decrease.

Carbon deposition: When spark plugs lose their ability to jump spark, they also cause incomplete combustion, which produces a burning substance called carbon deposition, and black smoke from car exhaust

Can l drive when my car has a faulty ignition coil?

If ignition coil has a faulty and the number of engine cylinders are misfire or two adjacent cylinders does not work normally at the same time, then the engine will most likely fail to start and the vehicle will be unable to run normally. If ignition coil only makes spark plug weak jump spark, the vehicle can be driven in this condition, but resulting in more fuel consumption, less power and other bad symptoms.