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A Beiqi pickup ordinary diesel vehicle equipped with 4D20 engine. Car owners reflect: the car often flameout, sometimes more than 10 minutes apart, sometimes one or two hours or even longer to be able to re - fire, and the flameout is irregular, sometimes when driving out of fire, sometimes stop to play without fire, completely irregular. When the car came, all the teachers were busy. The master on duty thought that it would be better to check again when there was a breakdown, so the owner drove away. At 8 o'clock on the second day, the owner called and said that he could not fight. He stopped at a county road which was about 15km from my factory, and asked for someone to repair it. As the teachers in the factory were busy, I ordered the factory to check when the car could catch fire. Who knew that at 10:30, the owner called again, said or couldn't, so I asked him to check the safety box under the cab, especially to check the flameout solenoid valve, the fuse, and shake the safety box under the driver's dashboard to see if it played. But the owner may have had this problem too many times. He said he had done that before, and the fuse did not burn. Once again, master rescue, in order to rescue the site effectively and quickly (because there are a few cars to be repaired in the factory, and two of them to rest), so I asked the details of the situation before and after the failure. Question 1: just now when the fire stopped, did it feel that it was going to be flameout at once or was there a lack of motivation before it was put out? Answer: all of a sudden go out. Question 2: is there any regularity in the process of fire after automatic fire extinguishing? Answer: completely irregular, look at luck. Sometimes it's ten minutes apart, sometimes it's two or three hours apart. And sometimes it looks like something is wrong. Sometimes the engine is flameout after flameout. At this point, I have a preliminary fault judgment, in order to confirm my guess, I like the original master once repaired this car to understand the following situation (because the owners do not understand, or because of maintenance technical problems should not be understood by the owner). Question 3: is this vehicle a high pressure common rail diesel or an ordinary cylinder direct injection vehicle? Answer: ordinary diesel car. Question 4: this car has been damaged due to the failure of the solenoid valve. It is said that it has been used for a few days. Has it ever heard of a failure or a midway fire? Answer: no midway flameout or unable to fight the situation, only can not extinguish; I heard that the owner also took the high-pressure oil pump. Troubleshooting: flameout solenoid valve failure, so that the teacher took a flameout solenoid valve to the scene rescue, solve the problem! 7 days after the return visit, confirm the correct solution to the problem! Fault summary: this fault is 100% determined in the process of telephone communication with the owner and master, and the following is the basis for analysis: the diagnosis conclusion of question 1 is that the car problem is not like the oil problem and should be the intake problem, but only the circuit / intake problem leads to this sudden extinguishment. The diagnosis of problem 2 is that the oil road problem is removed again, and the suspicion of the intake problem (the circuit caused by the intake) is aggravated (because the oil problem is usually low pressure fuel supply or high pressure return oil plugging, usually at a fixed time to be able to fire again). The diagnosis conclusion of question 3 is that the ordinary diesel vehicle does not involve the data of the electric spray and the crankshaft position sensor, but the factors that affect the direct injection of diesel vehicle in the ordinary cylinder are the pressure of the cylinder, the timing of injection, the gas supply and the oil supply. While the car has not moved anything, the inexplicable extinguishing can be able to fire without any regular intervals, and can work normally for several hours or even days, proving that the pressure of the cylinder, the fuel injection and the oil supply are normal. The diagnosis of problem 4 is that many times have happened before the fault should be done, and the car owners have taken the high pressure oil pump under the advice of other factories to eliminate the problem of oil supply again. The intake failure was indirectly verified. This case again proves the importance of fully understanding the working principle of the car during the maintenance process, and it is very useful to fully understand the details before and after the failure. This case is understood by different people according to different situations. Some details can not be directly understood by car owners, but will be better by indirect understanding. Many "technicians" in the process of maintenance did not know about the occurrence of a car's failure, the fault car came and repaired according to the failure phenomenon. As a result, the details of the fault occurred, including numerous information that could help the diagnosis, and sometimes it played 99% important roles in the judgment of the specific obstacle.