How to Solve Black Smoke from Diesel Vehicles?
2 Answers
Solutions for black smoke from diesel vehicles are as follows: 1. Remove the air filter and observe the exhaust smoke color. If the black smoke condition improves, the issue is caused by severe contamination of the air filter. 2. Check if the fuel supply timing is too early; if so, adjust it. 3. During engine operation, conduct a cylinder-by-cylinder fuel cut-off test. When cutting off fuel to a specific cylinder, if the engine speed decreases, black smoke significantly reduces, and knocking sounds weaken or disappear, it indicates excessive fuel supply to that cylinder. If the engine speed changes little but the black smoke disappears, it suggests poor spray quality of the injector in that cylinder. After identifying the faulty cylinder, disassemble and inspect the injector. If necessary, replace it with a new injector for comparison. If the issue disappears with the new injector, it confirms a fault in the original injector.
My diesel car used to emit black smoke, which was a real headache. It was mainly caused by incomplete combustion, possibly due to clogged fuel injectors, a dirty air filter, or poor fuel quality. I tried cleaning the fuel injectors and replacing the air filter myself, and the results were decent. But to truly solve the problem, the entire system needs to be checked: including whether the turbocharger is leaking, if the fuel pump pressure is normal, or even if the EGR valve is severely carbonized. Sometimes fuel additives can provide temporary relief, but in the long run, qualified diesel must be used. I recommend taking it to a repair shop promptly, as black smoke is not only unsightly but also damages the engine and increases fuel consumption. Regular maintenance is key—check the air system and fuel lines every 5,000 kilometers to prevent minor issues from turning into major repairs, saving money and ensuring safety.
