1, the phenomenon of failure
    A UCF10L-AEPGKV sedan (equipped with 1UZ-FE type engine, A341E type automatic transmission) produced by Toyota Motor Co., Ltd. is difficult to start. When the engine is running in the middle and low speed, the jitter is serious, and the engine is on the road. Phenomenon, the dashboard fault indicator (CHECK) sometimes flashing, but not bright, and the exhaust pipe has more white smoke discharge, a thick gasoline flavor, fuel consumption is very large.
    2, the reasons for the analysis
    The engine in the middle and low speed jitter is more serious, indicating that the engine of the eight cylinders in some of the cylinder does not work or poor work, resulting in engine operation is not smooth and jitter. Often caused by the engine cylinder is not working or poor work for the ignition system, the fuel supply system is poor or the cylinder compression pressure inconsistency. Because the exhaust pipe has more white smoke discharge, and the smell of gasoline is very strong, indicating that may enter a certain or a few cylinders of gasoline too much, resulting in combustible mixture is too strong, burning is not complete or simply can not burn. The direct cause of this situation is likely to be the failure of the injector, or the injector control circuit is faulty, it may be some of the cylinder spark plug does not flash.
    3, check the process
    A. First use the engine ECU fault self-diagnosis system to check the engine control system is faulty. The fault indicator on the dashboard displays the fault codes 11, 21, 26, and 27.
    In order to determine whether these sets of fault codes are true, first clear all the fault codes stored in the ECU, and then restart the engine, and let it work in low, medium and high speed conditions for a period of time, turn off after the re-call the fault code , Then the fault indicator on the dashboard shows fault codes 11 and 26. And then the road test, in the test process found that the car there is slow acceleration, idle car and self-flameout and many other failures, and the dashboard fault lights sometimes flash (but not bright), the test is completed and then retrieve the fault code is 11 , 21, 26 and 27, indicating that these sets of fault codes do exist.
    Fault code 11 indicates that the ECU power supply circuit has an instantaneous interruption phenomenon, 21 indicates the left main oxygen sensor and circuit fault, 26 indicates that the combustible mixture is too thick, 27 indicates the left side oxygen sensor and the circuit is faulty.
    B. Check the ECU power circuit EFI fuse (2OA) intact, the connection wire without breaking, short circuit, connector, connector without loosening phenomenon, the line is normal. Start the engine, running for some time after the touch in the 2 # junction box in the EFI main relay, feeling very hot, that EFI main relay is faulty. After replacing a new EFI main relay, start the engine and let it work for a long time and then touch it, feeling only slightly hot and the working temperature is normal. Indicating that ECU is indeed due to the original EFI main relay work caused by power supply power instantaneous interruption phenomenon.
   C. Remove the spark plugs of each cylinder and find that the spark plugs of the third and fifth cylinders are wet and the other spark plugs of the cylinders do not. This shows that the third cylinder and fifth cylinder into the gasoline too much, because the mixture is too thick and can not fire burning. The third cylinder and the fifth cylinder of the spark plug with electric furnace after drying together with the other six spark plugs re-installed, plug in the high-voltage ignition line, start the engine about 20min and then remove the spark plug check and found the first three and five The spark plug is soaked with gasoline. This is enough to show that the third cylinder and the fifth cylinder of the injector has been out of control, so that a large number of liquid gasoline into the cylinder, causing the mixture is too thick, can not burn and burn directly into the exhaust pipe, and other cylinders discharged by the hot exhaust gas mixture Was white smoke-like discharge. As the exhaust gas is not normal, a little longer will affect the oxygen sensor to work properly, but also likely to cause oxygen sensor failure or failure.