Shanghai Huapu car engine can not start
  • Automotive

A Shanghai Huapu car with a mileage of about 35 thousand km and a 8A engine. The customer is in other repair factories after the transmission, it is not easy to start the car phenomenon, after the car after the fire, and then can not start the car. Fault diagnosis: when we came to repair our factory, we first tested the cylinder pressure, all above 0.6MPa, indicating that there was no problem with cylinder pressure. When measuring the cylinder pressure, the spark plugs removed are wet, indicating the phenomenon of flooding. The fault code is extracted with the decoder, and the fault code "the throttle position sensor opens or short circuit to the positive pole", "the inlet temperature sensor opens or short circuit to the positive pole", "the coolant temperature sensor failure or the short circuit to the positive pole". After the fault code is removed, the fault of readout again remains, indicating that it is a hard failure. After changing the sensor to read the code, the fault code still exists. The throttle sensor voltage is measured. The three wire pair is 5V and there is no voltage between the three lines. The air inlet temperature and pressure sensor are all SV. According to the correct data, the throttle position sensor's 1 foot is 5V, but in February it is a signal, but in March it is a tie. But the actual measurement voltage and data are not consistent with the data. It is doubted that the contact iron contact is bad. It is possible to take the iron wire in the maintenance of the transmission. On the second day, the customer reflected the same fault. When reading the data flow, it was found that the intake temperature was 32 degrees, the coolant temperature was the same, and the throttle opening was 13.2 degrees. Looking at the circuit diagram, it is found that three sensors share a tie line. On the 30 foot of ECU, the 5V power is shared on the 12 foot of ECU and output after the ECU is connected to the power supply. Because the sensor plug has a 5V on the power supply, indicating that the ECU output 5V determines the sensor's opening of the wire. The 30 feet of the sensor ECU can't get through, but the vehicle can play, indicating that the ECU problem is not big. The only question is the line. Because the Huapu system is too small, the wire harness is not easy to buy, so the wiring harness inspection is removed, and the 30 feet of ECU are found to have "copper rust", the wire harness is easily dragged off, then 3. Foot, delivery owner use, the problem no longer appear. Maintenance summary: after the inquiring customer, the water tank has been replaced before the repair of the vehicle transmission, and the antifreeze liquid is spilled into the ECU plug for the water tank exhaust for a moment, resulting in the reaction between the wire harness and the antifreeze fluid, causing the thread to appear imaginary connection and cause the failure.