The explosion of unburned combustible mixture in the exhaust pipe is often accompanied by sparks, commonly known as shooting. The explosion of exhaust pipe will lead to high engine working temperature, poor acceleration performance and weak driving. The reasons are usually as follows:

1, carburetor is not adjusted properly.

The mixture is too strong. The residual combustible mixture caused the exhaust pipe to explode.

2, spark plug intermittent ignition

When the spark plug is poorly ignited or caught fire, the ignited mixture enters the exhaust pipe, and the high-temperature and high-pressure exhaust gas is discharged in the next combustion cycle, which is caused by ignition.

3. Ignition coil failure

If the ignition coil is damp or leaks electricity, and the high-voltage bag and spark plug are normal, it will also cause unstable ignition or fire, which will lead to shooting.

4. Valve timing failure

The engine valve clearance is wrong, the valve ablation is not tight, the valve phase overlap angle is too large, and the exhaust valve opens too early, which will also cause cannon sound.

5. The ignition time is too late

When the combustible mixture in the cylinder is completely burned, the exhaust valve has been opened, which makes the mixture burn in the exhaust pipe and causes deflagration.

6. Suspected detonation

I don't know whether to shoot or deflagrate. If it is deflagration, it is generally a carburetor problem, and the mixture is too thin.