What Causes Black Smoke of Diesel Engine?

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Black smoke from diesel engines is a common occurrence but some people still panic about it. So we often get asked what causes the black smoke of a diesel engine? It indicates that the engine has some kind of a problem and basically points to imbalanced fuel and air ratio or a more complicated issue. Normally, diesel engines should not produce almost any smoke while working, however, it’s normal for some older diesel to release some smoke when accelerating under load. there’s also white diesel smoke and even blue diesel smoke. So let’s do a quick rundown of what to suspect what you’ve got diesel smoke where it shouldn’t be.

The most common causes of black smoke from diesel engines include:

  • Dirty air filter. Black smoke indicates that the fuel is not burned properly. The internal combustion process in diesel cars requires a certain mixture of fuel and air. The ratio of fuel and air should be proper, otherwise, the mixture will be too rich, which will result in black smoke.

  • Faulty injectors. The injectors are an important part of your fuel system. They should open and close at a particular time and if that does not happen or they are clogged, they will end up injecting much more fuel into the cylinder. This faulty process forms solid carbon residue, which causes black smoke from the exhaust of the diesel engine when accelerating your car.

  • Dirty EGR valve. The EGR helps to re-circulate the engine emission by returning them to the combustion chamber and not sending them directly to the exhaust emission system. The carbon chucks could clog your EGR valve, which will result in loss of power, fuel inefficiency, and emission of black smoke from your exhaust.

  • MAF Sensor. It’s also important for the computer to measure the right amount of fuel that should be injected into the cylinder. The Mass AirFlow Sensor is responsible for the proper formation of the fuel and air mixture in the engine. If there is something wrong with it, it will register more airflow in the system and an additional amount of fuel will be injected into the engine. As a result, unburned fuel will turn into black smoke from your diesel engine.
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