What to do if you are experiencing black smoke, weakness and fuel consumption in your vehicle!

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Categories: Technology News

Maintenance Process

Asked the owner that the car is a used car, bought back and drove for more than a month, has been smoking, compared with other cars is too much fuel, and the black smoke is very large.

Find the diagnostic interface connected to the EPS1018, into the system to look at the fault code, showing U0078: CAN bus disconnect (ECU and DCU communication failure), P0100: DCU and ECU communication failure, two post-processing history fault code, then look at the post-processing it!

Exited the system into post-processing and found a fault code P2033: Waste Temperature Sensor (Group 1, Sensor 2) :Signal too strong, current fault.

Read the post-processing data stream to see the exhaust temperature is not normal. But this fault code does not affect the smoke, first solve this fault code.

First unplug the exhaust temperature sensor to measure the voltage are normal, suspect that the plug contact is poor, plug the copper wire found that the original plug back pin, deal with the fault code and then look at the history of the fault, by the way, measured the urea pump injection is normal.

Again with the car to observe the engine data flow found that the rail pressure is a little low, suspected of low-pressure oil circuit plug or high-pressure leakage, the oil circuit to play straight through or the same, remove the injector bench test, there is a return to the oil is large, after repairing the car after the test rail pressure is normal, black smoke is much smaller.

Repair to here black smoke there, doubt it will be insufficient air intake, just look at the data flow intake pressure is normal, is it exhaust blocked? Let the owner go up to the gas door, squatting down to listen to when the throttle is increased when you hear the exhaust rattling, demolition of the muffler down to see, it is really clogged, due to prolonged damage to the injector black smoke carbon buildup leads to catalytic converter scrapping, replacement of the new catalytic muffler, the fault is solved.

Maintenance Summary

Abnormal fuel injection, especially more fuel injection, resulting in abnormal air-fuel ratio, excess fuel without air for combustion, incomplete combustion, resulting in black smoke. If the injector wear will cause a large amount of fuel injection, in the same rail pressure and power time under the injector fuel injection is greater than the theoretical amount of fuel injected; if the injector oil volume is not properly adjusted, it will also cause the actual amount of fuel injected is greater than the theoretical amount of fuel injected, which will further cause the black smoke; Needle valve and the needle valve body wear, nozzle cracking will cause the injector dripping, on the one hand, the amount of abnormal injections, on the one hand, the moment is not right, will result in the engine black smoke. The engine will be black smoke.

Rail pressure sensor signal drift. If the rail pressure sensor actually measured rail pressure is lower than the actual rail pressure, then the amount of fuel sprayed out will be greater than the theoretical amount of fuel injected, fuel increase, the air does not change will be easy to cause black smoke. Rail pressure sensor signal drift is common is the sensor itself fault or contact terminal abnormality.