The ignition coil is a device that provides energy to the ignition system. As we know, the moving car is powered by the engine, and the engine produces energy by burning the mixture air-fuel in the cylinder, the ignition coil just like a transformer, which turns a low voltage into a high voltage in this process and the spark plug fire the mixture air-fuel. Generally speaking, the service life of the ignition coil is more than 100,000 kilometers. If your ignition coil does, please replace your ignition coil timely.

The layout of ignition coil 

The layout of ignition coil has designed in three ways: First, the ignition coil is placed in engine compartment, and the high-voltage current is distributed through distributor, and then transmitted to the spark plug through the high tension wires; The second is to place the ignition coil at the top of the spark plug, which is directly mounted on the spark plug. This design requires one ignition coil for each cylinder, and four ignition coils for a four-cylinder engine, although increasing the cost but more efficient. The third, the ignition coil is near the cylinder, as we know, coil-near-plug ignition system.

The ignition coil replacement cycle

Generally, the ignition coil will be replaced once for 100,000 kilometers. When the engine is running, the ignition coil often produces tens of thousands of volts of high voltage current. The ignition coil works in a high temperature, dusty and vibrating environment for a long time, inevitably causing aging or even damage. If the ignition coil is not replaced in time, it will have an impact on the engine's working performance. However, the 100,000km is not a fixed replacement cycle, and usually does not need to be replaced as long as the ignition coil works normally and the surface is not visibly aged.

The easiest way to determine the aging of the ignition coil is to open the engine compartment and observe whether the ignition coil has the symptoms of gum overflow, burst, and corrosion of connection parts and high pressure nozzle. If you want to know whether the ignition coil on the vehicle works normally, there is a simple and practical method: After the vehicle works for a period of time, hold the ignition coil with your hand, if you can do it, it means normal, if you can not hold (hot), it means there is a fault, generally the internal short circuit.

The symptoms of Ignition coil failure

1. Vehicle shakes at idle. Observe the exhaust pipe，the exhaust air is obvious intermittent, and the exhaust pipe shakes badly with the sound of "rur rur".

2. The speed is below 2500 RPM（revolution per minutes)when driving, the car obviously shakes and poor acceleration; When the speed exceeds 2500 RPM, the shaking disappear.

3. Open the engine cover, observe the running engine, whether the engine is severe shaking in the normal working state.

Whether ignition coil should be replaced together

If ignition coils need to be replaced because of aging, then even if only one fails, it is better to replace them all, as the others are in similar condition. If only one or two ignition coils fail, while the others are not affected and in good condition ( ignition coil usually  has a life of over 100,000km ), then you just need to replace the faulty one.