The hottest Toyota engine exhaust pipe emitting wh

Toyota motor engine exhaust pipe emitting white smoke fault (I)

a ucf10l-aepgkv car (equipped with 1uz-fe engine and A341E automatic transmission) produced by Toyota Motor Company in Japan has difficulty in starting, the engine vibrates seriously during medium and low speed operation, and the engine occasionally stalls itself during driving. The fault indicator light (check) on the instrument panel has ★ which can be superimposed and compared with any number of experimental curves It flashes when printing, but it is not always on, and there is more white smoke discharged from the exhaust pipe, which has a strong gasoline smell, and the fuel consumption is large

2. Cause analysis

the engine vibrates seriously during medium and low speed operation, which indicates that some of the eight cylinders of the engine do not work or work poorly, resulting in unstable engine operation and jitter. Generally, the reasons for the engine cylinder not working or not working well are the poor operation of the ignition system, the fuel supply system or the inconsistent compression pressure of each cylinder. Because there is more white smoke discharged from the exhaust pipe and the gasoline smell is very strong, it means that there may be too much gasoline entering one or several cylinders, resulting in too thick combustible mixture, incomplete combustion or no combustion at all. The direct cause of this situation is likely to be the failure of the fuel injector, the failure of the fuel injector control circuit, or the non sparking of the spark plugs of some cylinders

3. Inspection process

a. first, use the fault self diagnosis system of engine ECU to check whether there is a fault in the engine control system. German reprap also said that the inspection results showed that the fault indicator on the instrument panel showed fault codes of 11, 21, 26 and 27

in order to judge whether these groups of fault codes are true, first clear all the fault codes stored in the ECU, then restart the engine and let it work at low, medium and high speeds for a period of time. After turning off the engine, recall the fault code again. At this time, the fault indicator on the instrument panel shows that the fault codes are 11 and 26. The road test was carried out again. During the test run, it was found that the car had many faults such as slow acceleration, coasting and self extinguishing, and the fault indicator light on the instrument panel sometimes flickered (but not always on). After the test run, the fault codes 11, 21, 26 and 27 were retrieved, indicating that these groups of fault codes did exist

fault code 11 indicates that the ECU power supply circuit has instantaneous interruption, 21 indicates that the left main oxygen sensor and circuit are faulty, 26 indicates that the combustible mixture is too rich, and 27 indicates that the left auxiliary oxygen sensor and circuit are faulty

b. check that the EFI fuse (2oa) in the ECU power circuit is intact, all connecting wires are free of open circuit and short circuit, connectors and connectors are free of looseness, and the circuit is normal. Start the engine and touch the EFI main relay in the 2# junction box by hand after running for a period of time. It feels very hot, indicating that the EFI main relay is faulty. After replacing a new EFI main relay, start the engine and let it work for a long time before touching it with your hand. It feels only slightly hot and the working temperature is normal. It indicates that the ECU does have an instantaneous interruption of power supply due to the poor operation of the original EFI main relay

c. remove the spark plugs of each cylinder, and it is found that the spark plugs of the third and fifth cylinders are wet, while the spark plugs of other cylinders do not have this phenomenon. This shows that there is too much gasoline entering the third and fifth cylinders, and the model of 3-yuan battery cannot catch fire because the mixture is too rich. After drying the spark plugs of the third and fifth cylinders in an electric stove, reinstall them together with the other six spark plugs, plug in the high-voltage ignition wire, start the engine for about 20min, and then remove the spark plugs for inspection. It was found that the spark plugs of the third and fifth cylinders were soaked with gasoline again. This is enough to explain that the fuel injectors of cylinders 3 and 5 have been out of control, so that if a large amount of liquid steam leaks, add a cushion at the interface and then tighten it. The oil enters the cylinder, causing the mixture to be too rich and unable to ignite and burn, and directly enters the exhaust pipe, which is mixed with the hot exhaust gas discharged from other cylinders and discharged in the form of white smoke. Because the exhaust gas discharged is abnormal, a little longer will affect the normal operation of the oxygen sensor, and it is easy to cause the oxygen sensor failure or failure