Why Is the Car Ignition Coil Easy to Burn out? How to Judge?

Nov. 13, 2020

Ignition CoilThe car ignition coil is composed of the main coil, a secondary coil, a magnetic core, a switching triode, and other auxiliary components. The main coil is charged by a battery, the secondary coil is discharged by a spark plug and the triode is responsible for switching. The charging time is controlled by the battery voltage and the engine speed to ensure that the energy of each charge is consistent. The ignition coil has two types: 3-wire and 4-wire. The 3-wire is the power supply positive, negative, switch control (ECU command), and the 4-wire has one more ignition detection. The wire can detect whether the spark plug is ignited (whether there is a discharge current in the secondary coil).

To put it simply, the ignition coil is a transformer, which increases the voltage of tens of volts to tens of thousands of volts, but the voltage input to the primary coil is provided by the electronic igniter. When the voltage changes within the specified range, the transformer will not be burned. Usually, the burning of the transformer occurs when the transformer load is too heavy. Therefore, when solving this problem, we must try to find out what caused the overload or the components Causes of aging.


Causes of Ignition Coil burnout

Ignition coil burnout is mainly caused by the aging and breakdown of the insulation layer or the damage of the switching transistor. The large gap between the spark plugs will cause the main coil to load, generate heat, and the insulation layer will age quickly. The small gap between the spark plugs will cause the secondary coil to discharge current, heat, and insulation Fast, the assembled ignition coil may have a shorter life due to poor insulation material durability, the large internal resistance of the coil, high heat generation, and low-quality tertiary tube.

If it is always burned out, it will burn out soon after replacement. What is the reason? Here is some summary:

1. First look at the generator. If the power generation is too high, the ignition coil will burn out if the load is too heavy, but if the power generation is really too high, then the body electrical appliances, such as light bulbs, will often be damaged;

2. Of course, the quality of accessories is not ruled out, so it is best to measure the power generation first;

3. The spark plug gap is too large, adjust the gap or replace the spark plug;

4. The gasoline quality is not good, try changing to higher-grade gasoline;

5. The cylinder compression ratio is wrong, adjust the compression ratio;

6. If there is a program failure on the computer board, you can go to the repair shop to use the computer to check the car and clear the error message; if it does not work, it may be that there is a problem with your car's transmission;

7. The power supply voltage is unstable;

8. The resistance of the high-voltage line is abnormal, replace the high-voltage line;

9. There is a short circuit phenomenon in the secondary;

10. The primary current of the ignition controller is too high, causing the ignition coil to overheat;

11. It is not good to work due to problems with high temperature and high-pressure waves;

12. The small chance is the problem of the coil itself, you can try another brand;

13. The igniter integrated block works poorly.


Detection method

The crankshaft position sensor (CKP) and camshaft position sensor (CMP) detect normal, but there is no high voltage fire, usually the ignition coil assembly power wire is open.

1. Test with a high-impedance multimeter and light-emitting diodes: For models with no distributor ignition, first, unplug the 4-channel ignition coil primary winding plug, and use a high-impedance multimeter to detect 3 to 4 holes. The voltage should not be less than 11 V. Then connect light-emitting diodes to holes 1, 4, and 3 and 4 respectively. If the light-emitting diodes do not flash when the engine starts, it means that there is no low-voltage signal, and the low-voltage circuit should be checked. The power transistor failure will affect the ignition control signal. The power transistor is the ignition control signal amplifier. Turn off the ignition switch, connect the light-emitting diode between the positive electrode of the battery and the power transistor terminal a, and start the engine to run for 10s. If the light-emitting diode does not light up, The power transistor should be replaced.

2. Resistance value test: The resistance value of the ignition coil is directly related to the quality of the ignition performance. If there is no fire or weak spark, the resistance value of the primary winding and the secondary winding should be checked. If the resistance value is within the range specified by the manufacturer If the resistance value is too low, it means an internal short circuit; if the resistance value is too high, it means an internal open circuit. If the measured value does not match the manufacturer's regulations, it must be replaced.

3. The main feature when the ignition coil is about to be damaged is that the ignition coil is hot and hot.

4. In traditional cars, the main reason for checking the ignition coil failure is to look at the high-voltage flashover. Under the premise that the low-voltage circuit is normal, if the ignition coil is not faulty, the flashover should be a strong blue spark. The ignition coil of electronic fuel injection is mainly used to measure the impedance of the primary and secondary windings and to measure the on-off of the circuit with light-emitting diodes.

5. If the spark plug of a certain cylinder is found to be non-fire or work poorly, unplug the high-voltage branch line of the cylinder, connect a new spark plug, and spark at a distance of 8 mm from the cylinder body. If it is normal, it means that the fault lies in the original spark plug.

6. Suddenly there is no fire or weak sparks during driving. Infrared thermometer or hand touch can be used to determine whether the ignition coil or ignition module has an internal short circuit or open circuit fault. When the fault is judged, it can also be restarted. Regardless of whether it can be started, it can be judged by measuring the temperature of the automotive ignition parts.

①The ignition coil is overheated: the surface temperature of the ignition coil is greater than 95℃, indicating that the ignition coil is short-circuited and must be replaced.

②The ignition coil is too cold: the surface temperature of the ignition coil is equal to the ambient temperature when starting, indicating that the ignition coil is open and must be replaced.

③The ignition module is overheated: the temperature of the ignition module is higher than 100°C, indicating that the ignition module is short-circuited and must be replaced.

④Ignition module is too cold: The ignition module and the ambient temperature are equal when starting, indicating that the ignition module is open and must be replaced.