Symptom: a Toyota Sequoia US regulation of the car, the owner reflects the new car has been driving 200,000 km, there are difficulties in the engine hot and cold cars, when the engine after the start of an idle normal work, when the emergency when the engine speed , The owner of the fault will drive into my maintenance center for maintenance.
    Failure analysis: For difficult to start the fault phenomenon, first check the engine with or without fault code exists. With OBD2 fault detection diagnostic device connected to the fault diagnosis connector, open the ignition switch, read the engine fault code, found that the car without fault code exists. After the engine starts for a while, read the data flow of the engine and find that the data flow is normal. The temperature of the water temperature is 82 ℃, the inlet temperature is 40 ℃, and the data flow is normal. Proof of this car data stream is also normal. We start checking from the oil. Connected to the fuel pressure gauge, check the fuel pressure of 300kPa, fuel pressure is normal, in line with the pressure of electronic fuel injection system. We checked the other control system of this car and found it normal. Carefully asked the owner of this car failure, the owner has been reflected in the far door, in other gas stations plus oil.
    Failure to solve: We take into account the fuel oil is not caused by the phenomenon of failure? We opened the fuel tank and found the fuel color was cloudy, and the fuel contained impurities. Maintenance workers will be net of oil, re-put the new fuel, the entire oil clean, remove the nozzle, with the nozzle to automatically clean the instrument for cleaning and found that there are impurities inside the fuel nozzle, dirt was washed out The Reload the fuel injector, start the engine, the engine easy to start, work properly, troubleshooting. Modern electronic fuel engine, due to different internal structure and design of the fuel engine oil, oil quality made a high demand, must use the vehicle to meet the specifications and specifications of the fuel, otherwise it will cause three-way catalytic converter, oxygen sensor , Nozzle, etc. failure, and even lead to failure. Therefore, for the owner, the choice of oil and oil must pay attention to the provisions of the model, specifications.
    Conclusion: The above example is because the fuel quality of this car is not right, the oil contains impurities, the engine at the beginning of work, the precipitation of oil blocked the nozzle of the injection hole, affecting the engine fuel injection, causing the The engine is difficult to start the fault.