A Buick excel 1. 6L car with a mileage of about 110 thousand km. Users reflect: the engine is intermittently extinguished. When driving, the engine is extinguished automatically. Sometimes it is suddenly flameout at high speed. Sometimes it is low speed, sometimes it is cold car to extinguish, sometimes it is the heat of the car, and the fault is not regular. After the engine is extinguished, the engine can not start the car immediately, and it can start after about a few minutes. Fault diagnosis: using TECF12 to detect engine electronic control system, there is no fault code memory. Because of each failure, the maintenance personnel are not in the scene, the vehicle can not be reproduced after the return of the fault, do not know the oil road failure or circuit fault, maintenance has no target. Check the wiring harness of the relay box, the line harness of the gasoline pump, the wire harness of the engine rear starter, the shotcrete wire harness, the ignition coil wire harness, the engine speed sensor plug and wire harness, and have no damage or bad contact. Tightened the battery to the car body, the battery and the body, the gasoline pump and the gasoline pump, and the customer picked up the car. But a week later, the customer returned the car again and said there were two more stalls. Because of the last inspection of the line, wire harness, power supply and bypass, and the replacement of the gasoline pump, it is not valid. This time the focus is on the components of the ignition and fuel injection system, including the ignition coil and the crankshaft position sensor, which can cause the engine to be extinguished. When the engine is running, pull the components and wiring harness in the engine compartment, and the engine is not turned off. The lifting vehicle pulls the components and wiring harness under the engine compartment while the engine is running, and the engine does not extinguish. The screw handle is used to tap the crankshaft position sensor and the engine stall. The fault may be caused by the bad position of the crankshaft position sensor. The 1. 6L crankshaft position sensor circuit is an electromagnetic sensor with three wiring, its 1 feet (brown line) and 2 feet (blue line) at both ends of the electromagnetic coil, at room temperature the resistance is 600~660 Omega, 3 feet (black / white line), the shielding end, and the barrier between the two signal lines is infinite. To disconnect the crankshaft position sensor plug, the resistance between the blue line and the brown line is 667 Omega, and the resistance between the black line and the blue line is sometimes infinitely large and the measurement results are normal. The crankshaft position sensor is tapped with the rubber handle end of the screw screw, and the resistance between the blue line and the brown line is changed to infinity. It shows that the signal line circuit of the crankshaft position sensor has discontinuous circuit breakdowns. Replace the crankshaft position sensor, troubleshooting.