Failure phenomenon: a 2004 three car flying car, the car has been running nearly 200 thousand kilometers, the owner described: the car in the course of the engine suddenly flameout, and can no longer start. Fault diagnosis: according to the condition of the vehicle, only 10 thousand km driving, there should be no big problem. Turn on the ignition switch, the indicator light is all right, turn the ignition switch to start the engine, the starter will turn strong and the speed is enough, but the engine will not start. Start with simple and complicated thinking, first check the oil circuit. The engine belongs to the program controlled fuel injection system, and the fuel pump is controlled by computer. Turn on the ignition switch and stop after 2S, and work continuously after engine starts. So turn the ignition switch on and off, turn on 2S and turn on 2S. Open the fuel tank cover to listen to the oil pump work, found that the fuel pump has the start of the hissing sound, open the engine room to pull off the fuel intake pipe has fuel pump out, initially proved the normal oil road. Next to the circuit, the car's ignition system uses the Honda's latest I-DSI (intelligent independent double ignition), each with two ignition coils and a spark plug. Torishita Ichi, two cylinder front ignition coil and spark plug found that the spark plug has very wet gasoline liquid, insert the spark plug into the ignition coil and put it on the cylinder cover, and start the spark plug without jumping spark, indicating that the ignition system is in trouble. Unplug the three core plug of the ignition coil of the car. The colors of the three lines are black / yellow (power line), white (computer controlled return route) and black (tie line) respectively. To turn on the ignition switch, first use the multimeter to measure the black / yellow (power supply line) voltage, and no voltage. According to the circuit diagram, the fuse No. 14 and 15 in the driver's side box were found to be burned. The 14 is the front ignition coil, and the 15 is the rear ignition coil. Replace the new fuse and fuse immediately after the ignition switch is switched on. It is obvious that there is a short circuit in the ignition system. Using multimeter to measure the safe socket No. 14 and 15 in the safety box, find the short circuit of the power supply to the ground, and find out all the normal wiring. When all the ignition coil plugs were removed, the short circuit of the socket was found to disappear. The eight (first four and four) ignition coils were removed and measured one by one, and it was found that the front and rear ignition coils of the two cylinders were short circuited internally. Failure analysis: under the condition of oil and fire, the machine and control system can only be considered. The engine used the advanced silent chain at the time of the engine, and only ran for 10 thousand km. Honda special HDS diagnostic system was used to enter the vehicle computer, and no failure codes were found. Looking at the data flow, all the signals are normal. The engine speed was only 60r/min when the engine was started. The engine speed signal is obtained by the crankshaft position sensor, so the crankshaft position sensor is removed to measure its resistance, and it is found that the end of the sensor (the part of the signal obtained with the crankshaft trigger wheel) has very obvious wear. The crankshaft position sensor is electromagnetically induced, and the rotational speed of the engine is obtained by the rotation of the crankshaft trigger wheel. In normal circumstances it has a certain gap with the crankshaft trigger wheel, and it should not be worn. So it is doubted that the trigger wheel is having problems and is ready to remove the oil pan inspection. When the vehicle was raised, it was found that the oil pan had collided. After the collision, the oil pan was removed for re welding. Then we dismantled the oil pan and found that the crankshaft trigger wheel had been cracked to three, of which two had fallen into the oil pan, and the teeth on a small portion of the trigger wheel could only give the sensor a low engine speed signal, causing the engine to burst but could not start. Troubleshooting: after the trigger wheel is replaced, the engine starts successfully at one time, and enters the computer system with HDS.