Symptom: Santana 2000 car mileage of more than 10 million km. The engine in the slow acceleration of the engine work is acceptable, but in the rapid acceleration when the engine serious jitter, and tempering "blasting". Troubleshooting: first with the king repair fault detector to read the fault code, no fault code display. Observe the data flow, in addition to fuel injection time is too long (5.5ms), the rest is normal. As a result of no fault code, the data flow is normal, so start from the non-electronic control part. Has checked the fuel pipeline, high voltage line, ignition coil, spark plug and valve mechanism, etc., no exception. Remove the injector and find the carbon deposits attached to the injector head. The injector with ultrasonic cleaning machine after cleaning, the fault has improved, but there are accelerated tempering "shot" phenomenon. Then check the data flow and found that the fuel injection time is shorter, about 4.8ms, but compared with the standard value, but also long.
    From the fuel injection time to analyze a lot of factors, such as engine load, coolant temperature, air flow, intake air temperature and oxygen sensor feedback signal, can directly affect the fuel injection time. So it has measured the coolant temperature sensor and intake air temperature sensor resistance, are normal. As the idle state is not open air conditioning, no turning steering wheel, the whole car are in a closed state, so there is no problem of increased load. Oxygen sensor feedback to the ECU oxygen content signal sampling rate of 8 times / 10s, also normal. It will not be the air flow sensor problem? Replace the air flow sensor after the test, troubleshooting.
    Failure Analysis: This is a typical air flow sensor in the detection of air flow in the process of signal failure. Since the air flow signal data obtained by the ECU does not coincide with the standard signal data of the engine at the time of operation, and this changed data does not exceed the data in the ECU memory, there is no fault code. At the same time because the ECU can not detect the air flow sensor is faulty, so still according to the air flow sensor gives the wrong signal to determine the fueling duration, which will inevitably lead to fuel injection is not normal. However, due to the feedback signal of the oxygen sensor to correct the fuel injector fueling duration, so the engine speed change rate is not large, the failure phenomenon is not obvious, because it will be in every 10s time feedback to the ECU 8 ~ ​​10 times Oxygen content signal, making the engine in this case can also barely work; but when the rate of change in speed increases, because the oxygen sensor to the ECU oxygen content signal sampling rate is far from the engine speed changes faster, then also It can not fix the fueling duration, so the engine in the rapid acceleration of tempering "blasting".