What causes black smoke from a Weichai engine when accelerating?

[McAdrian]

The reasons for black smoke appearing momentarily when accelerating a Weichai engine are as follows: 1. Combustible mixture: The combustible mixture is too rich. 2. Engine oil quantity: Excessive engine oil in the fuel. 3. Piston rings or crankshaft: Poor sealing of piston rings or crankshaft oil seals. 4. Fuel: Presence of water in the fuel. 5. Spark plugs: Faulty spark plugs. Fault diagnosis and troubleshooting: 1. Inspection and diagnosis of an overly rich combustible mixture: Focus on checking the carburetor and air filter. 2. Incorrect mixing ratio of mixed oil and engine oil: Or using the wrong grade of engine oil. If the mixed oil contains too much engine oil or the engine oil quality is poor, the engine oil in the combustible mixture cannot burn completely, resulting in black smoke. For two-stroke engines with separate lubrication systems, an improperly adjusted oil pump supplying too much oil can also cause this phenomenon. In this case, the oil pump should be inspected and adjusted as per regulations to ensure proportional supply of lubricating oil at different throttle openings. 3. Excessive wear or breakage of four-stroke engines, as well as excessive oil in the crankcase: Both can cause oil to enter the combustion chamber, leading to excessive oil in the mixture. If the crankshaft oil seal of a two-stroke engine is damaged, it can also allow oil from the transmission to enter the crankcase and subsequently the combustion chamber with the mixture.

[JaceLynn]

I've driven vehicles with Weichai engines for many years, and I've seen the issue of black smoke during acceleration many times. The most common cause is when too much fuel is injected at once, leading to incomplete combustion. For example, during long-distance driving, I've encountered situations where the fuel injectors were dirty or worn out, or the fuel pressure was too high, causing excessive fuel delivery and resulting in unburned fuel and black smoke. Lack of air intake can also cause this—if the air filter is clogged and restricts airflow into the engine, the fuel-to-air ratio becomes imbalanced, leading to black smoke. Faulty sensors, like an oxygen sensor providing inaccurate readings, can mislead the system into injecting more fuel than necessary, wasting fuel in the process. If ignored, this can lead to carbon buildup and increased emissions, making the engine feel sluggish and noisy. My advice is to start by checking simple components, such as replacing or cleaning the air filter. If the problem persists, take the vehicle to a repair shop to inspect the fuel injection system and ECU adjustments—don't let minor issues escalate. Regular maintenance is key to avoiding this hassle.

[Tom]

I used to worry a lot about black smoke coming out when refueling. When I first started driving, I encountered this issue frequently. Now I understand that it's mostly due to an imbalance between fuel and air. For example, a leaking fuel injector can deliver excessive fuel, and an improperly adjusted fueling system during sudden acceleration can cause this. If air can't get into the engine—perhaps because the air filter is too dirty and blocking airflow—it can also lead to combustion problems and black smoke. There are also minor details, like a malfunctioning coolant temperature sensor misleading the system into delivering too much fuel during refueling. This affects emission efficiency, making the car run slower and consume more fuel than before. My usual approach is to first check if the air filter needs replacing and clean the vents. If the problem persists, I don’t push it and promptly take it to a reliable repair shop for diagnostic testing with professional equipment. Remember, don’t ignore it, as it could lead to increased engine wear or even fines.

[LeIan]

I've driven several vehicles including Weichai models. Black smoke during acceleration is usually caused by incomplete fuel combustion, mainly due to several reasons: stuck injectors delivering excessive fuel, insufficient air intake from blockages, faulty sensors causing the system to misinterpret fuel requirements, or a dirty fuel filter affecting supply. This can lead to decreased engine performance, unpleasant odors when smoking occurs, and potential carbon buildup. The solution is regular maintenance such as replacing filters. If the problem persists frequently, professional inspection of ECU settings is necessary. Don't delay to avoid damaging the vehicle.