The mixture is the gas after the mixture of fuel and air, and the concentrated gas of the mixture represents more oil and less gas, on the contrary, the dilution of the mixture means that the gas is more and less oil. Therefore, there are two main reasons for the excessive concentration of automobile engine mixture, one is the oil road problem, the other is the gas circuit problem, and these two large aspects can be subdivided into many small problems after the expansion, let's take a look at it together.
Oil circuit problems (too much oil)
First, the gasoline pressure is too high, mainly caused by the damage of the fuel pump and the fuel pressure regulating valve, which will cause the amount of oil injected into the injector nozzle to be too large, so that the mixture becomes thicker, and the solution is to replace the oil pump and the regulating valve.
The second is the injector drip, it will cause the engine to leak fuel into the combustion chamber without the need to inject fuel, resulting in excessive gas mixture, when inspecting, the injector can be removed to observe whether the oil is dripping, if the fault is true, you need to replace the new injector to solve.
The third is the leakage of high-pressure oil pump, for models with high-pressure oil pumps, this is one of the most common reasons for mixed gas concentration, but in essence, there is no difference between it and the injector drip, but the high-pressure oil pump is leaked inside the engine and mixed with the oil to form part of the fuel vapor, which affects the proportion of the mixture, which in turn leads to excessive concentration of the mixture. In the inspection, you can unscrew the oil cover, smell whether there is a strong gasoline smell in the engine, if the smell is obvious, it is damaged by the high-pressure pump, and it can be solved after replacement.
Fourth, the water temperature sensor is inaccurate, this sensor is to correct the amount of engine fuel injection, when the engine water temperature is low, the ECU will increase the amount of fuel injection to warm up the engine as soon as possible, so as to achieve better combustion efficiency, when the engine water temperature reaches the right temperature, the ECU will reduce the amount of fuel injection. If the water temperature sensor is inaccurate, it may also be corrected when the water temperature sensor is cold during the hot car, thus triggering the phenomenon of mixed gas concentration, and the solution is to replace the new water temperature sensor.
Fifth, the front oxygen sensor is damaged, the former oxygen is mainly used to detect the oxygen content in the exhaust gas, so as to adjust the amount of fuel injection according to the detection results, if the sensor is in a damaged state, the oxygen concentration in the exhaust gas is too high, the ECU will increase the amount of fuel injection to correct the ratio of fuel to air, thereby triggering the failure of the mixture gas concentration, the solution is to replace the oxygen sensor.
Sixth, the engine control unit is damaged, it belongs to the core and hub of the entire engine electronic control system, responsible for collecting sensor signals and issuing instructions, if it is damaged, it will issue the wrong injection instructions, thereby affecting the air-fuel ratio, resulting in the current situation of mixed gas concentration, the solution is to replace or repair the ECU control unit.
Airway problems (low gas)
First, there is an air leakage in the engine, this air leakage is mainly the presence of the turbocharger to the throttle end, the general engine control unit will report the failure of the pressure drop, etc., and can use the smoke leak detector to detect when processing, and then repair the damaged location to solve.
The second is the blockage of the air intake system, such as the reduction of the air intake volume of the engine due to the dirty air filter, which will cause the mixture to be concentrated, and the solution is to replace the dirty air filter and clean the blocked air intake pipe.
The third is the air flow meter or inlet pressure sensor damage, they are mainly used to detect the intake volume and intake temperature, if the accuracy is damaged, it will be falsely reported intake data, thereby affecting the amount of fuel injected by the engine caused by the mixture of gas concentration, the solution is to replace the new sensor.
Fourth, the gasoline steam recovery system failure, the system will introduce the fuel vapor in the tank into the engine combustion, if the carbon tank solenoid valve is stuck and normally closed, it will cause the fuel vapor to decrease, thereby causing the failure of the mixture gas concentration, the solution is to replace the carbon tank solenoid valve. However, it should be noted that if the carbon tank solenoid valve is in the normally open state, there will be a failure of first thickening and then dilution.
Fifth, the engine has more carbon deposits, after the formation of carbon deposits, it will adhere to the throttle body and spark plug, and the more carbon in the volume of the throttle will affect its opening, resulting in a reduction in the intake volume, resulting in a thick mixture; the carbon deposition on the spark plug will weaken the ignition energy, so that the mixture cannot be completely burned, resulting in the failure of the mixture.
The above is the common reason for the excessive concentration of engine mixture, you can refer to it, there is something wrong with you please advise.