A 2004 Changan Ford Carnival 1.6 car with a mileage of about 157 thousand km. It is difficult to start the car. If it doesn't work in time, it will immediately turn off. According to the car owner, the car was just started in the morning, the engine idling speed changed between 800 and 1000r/min. After the water temperature was normal, the phenomenon of the idle speed was also disappearing. But recently, the engine started to start trouble and start up after the failure. Fault diagnosis: after the repair technician receives the car, it starts the engine and keeps the speed above 2000r/min. The engine makes drastic noise while the engine is drastically jitter. Then the fuel engine is immediately extinguished, the instrument indicator is normal, and the engine computer no fault code output is inquired with the Ford special detector WDS. There are 2 reasons that can cause the engine to start difficult and start immediately after starting the fire. One is to break the fire, that is, not enough spark to ignite the combustible mixture; the two is to break the oil, usually because the electronic control part of the fuel system is malfunction, or the fuel injector, the fuel line is blocked, so that the fuel can not be ejected in time. Go in the combustor. According to this idea, check the ignition system and the fuel system respectively: check the ignition system, the spark plug has a black carbon deposit on the surface of the electrode, and a small amount of gasoline. After replacing a new set of Ford special spark plugs, the high pressure jump fire is normal, but the failure is still. Measuring cylinder pressure: cylinder pressure is between 900- and 1000kPa, and the pressure difference between cylinders is not large. It seems that there is no problem with cylinder pressure. No exceptions were found in the socket of engine wiring and other actuators. Measure the fuel pressure: after the fuel pressure gauge is connected, start the engine again, the oil pressure is 270kPa, normal. After pulling out the vacuum tube on the fuel pressure regulator, the fuel pressure rises to 340kPa. These values indicate that the fuel system is not likely to go wrong. It is a little confused to check the maintenance technician here. According to experience, the fault location should be in the fuel system, but the fuel pressure is measured in the normal range, and the car's mileage is not much, and the injector should not be blocked. So is there no fuel injection? After starting the engine and stepping on the accelerator pedal, we can see that the fuel injection signal of each cylinder has output. The only place that did not check was the fuel injector. The fuel injector removed from the fuel rail, found that there are many impurities in the fuel guideway, the truth is finally clear. The fuel injector and fuel rail are removed and cleaned, and all the remaining fuel in the fuel tank is replaced. After commissioning, everything is normal and the trouble is completely eliminated. Later, the owner recalled that the malfunction of the car really occurred after adding one oil. Because the fuel contains a lot of impurities, although there is filter filter in the fuel system, but when the impurity is too much, some impurities can not be filtered out. Finally, it stops at the injector, causing the injector to plug and the engine oil supply is insufficient, resulting in the above barrier.