What is the reason for the car accelerator to step on the exhaust pipe?

The explosion of the exhaust pipe may be caused by the excessive mixture, and the combustible mixture of the engine cannot be completely burned because of the excessive mixture. With the exhaust gas, the unburned combustible mixture enters the exhaust pipe, meets fresh air in the exhaust pipe, burns again and explodes. This phenomenon is called exhaust pipe blasting, which is an explosion when combustible mixture burns in the exhaust pipe. Not only reduces the engine power, but also increases the fuel consumption. Sometimes the strong expansion pressure is enough to make the exhaust pipe or muffler burst. The first possible reason for this phenomenon is that the mixture is too thick and the discharge is not sufficient: (1) First, check whether the fuel injection quantity of the injector is too large and whether there is excess fuel injection; (2) Check whether the oil pressure is too high; (3) Check whether the intake pressure sensor is in good condition and the oxygen sensor in the exhaust pipe is in good condition. The second possibility is poor ignition: (1) Check whether the spark plug gap is too large; (2) Whether the high-voltage ignition wire of the engine leaks electricity. The causes of exhaust pipe shooting are too rich and too thin mixture, valve leakage, spark plug failure, ignition system problems and so on. Turn on the ignition switch and press the start button to start smoothly; Road test in gear, smooth speed increase, no adverse reaction; When the accelerator is pressed, there is a shooting sound in the exhaust pipe. Because the start and acceleration are smooth, the valve leakage can be ruled out, which also shows that there is no problem with the ignition system. Due to the high compression of this car, the crankshaft has high-speed reciprocating inertia during the throttle release process, and the concentration of combustible mixture is higher than that at idle speed. In order to meet this requirement, an instantaneous enrichment device-air cut-off valve is added to the carburetor. The main function of the device is to thicken the combustible mixture at the moment when the engine changes from high speed to low speed, so as to prevent the occurrence of ignition. If something goes wrong, the exhaust pipe will shoot as soon as the throttle is released. So the block valve on the carburetor was checked, and the negative pressure pipe was well connected and there was no air leakage, so it was decomposed. Sure enough, the small diaphragm inside is broken, the elasticity of the small spring is good, and it is no problem to control the gas circuit switch. Replace the diaphragm, reassemble it, the shooting phenomenon disappears, and troubleshooting. It is suggested to change the oil or adjust the ignition time if the blasting is not good. @20 19