Why is the engine black?

Black smoke indicates that there are too many carbon particles in the exhaust gas, which is caused by incomplete combustion when the engine is running. When the air filter is too dirty, the spark plug is not good, and the ignition coil is faulty, the engine will emit black smoke.

First, the car exhaust inspection steps

Whether the vacuum hose connection (under the throttle) is blocked or not, you can replace it with a new spark plug before starting it. If it is removed after working for a period of time, check whether there is carbon deposit in the spark plug. If not, it has been solved. Some faulty cars will emit black smoke for a long time because of the residual carbon deposit in the exhaust pipe and the three-way flower promotion. Check whether the throttle position data is correct. The oxygen sensor is only an emission sensing element. If the computer fails due to sensor failure, or the air inlet leaks, the exhaust gas naturally exceeds the standard, and the black smoke emitted by a single vehicle is generally caused by computer failure, inaccurate vacuum signal or even error. In addition, check the timing of the pulley and pay attention to whether the crankshaft is worn or deformed.

Second, the causes of black smoke from cars

(1) General reason

1, air filter blocked;

2. There is something wrong with the injector, such as poor atomization, dripping or high injection pressure;

3, the fuel system pressure is too high, such as the oil return pipe is blocked, the oil supply is too large, or the regulator is faulty;

4. Air leakage;

5, the vacuum degree is reduced;

6. The energy of the ignition system is too low, such as the weak spark plug, which causes carbon deposition and affects the combustion quality;

7, the valve seal is lax, internal leakage;

8. Improper adjustment;

9, cylinder and piston fit clearance is too large;

10, the ignition timing is misplaced, which will make the mixture burn incompletely; Or a few cylinders of the engine don't work, which will emit a small amount of black smoke;

1 1, the mixture is too rich, that is, the air coefficient of the excess mixture in the cylinder is too small, and the combustion is incomplete. Some fuel oil is decomposed into free carbon at high temperature and discharged from the exhaust pipe, resulting in black smoke.

(B) the reasons for electronic control

1, oxygen sensor failure, such as the power supply line is open and cannot be heated, and the oxygen sensor itself is poisoned or dirty;

2. There is something wrong with the air flowmeter, such as metering error or maladjustment;

3. The cold start injector is faulty;

4. Failure of the fuel pressure regulator, such as damage or blockage of the vacuum hose of the oil pressure regulator, sometimes causes the vacuum of the regulator to be out of control, resulting in high fuel pressure;

5. The throttle position sensor and its circuit are faulty;

6. The intake pressure sensor is faulty, for example, it cannot provide normal intake pressure signal;

7. The coolant temperature sensor is faulty, for example, the temperature of the coolant cannot be provided correctly;

8, ECU computer program failure;

9. Assembly error, such as connecting the vacuum tube of the intake pressure sensor to the intake manifold (it should be connected to the throttle body).

Third, solve the problem of black smoke from cars.

1. Repair and replace corresponding accessories, such as air filters, fuel injectors, valve seals, cylinders and pistons, oxygen sensors, etc.

2. Clean the corresponding accessories to avoid blockage. Air filters and fuel injectors are accessories that are frequently cleaned.

3. Driving habits are also very important. If you step on the accelerator often, the problem of black smoke from cars will be aggravated and often happen.

4. Always check a series of accessories, including system oil pressure, air filter, oil supply system, intake system, intake system and intake pressure sensor, circuit, spark plug and ignition circuit, oxygen sensor, flowmeter and related circuits, fuel injector related circuits, pressure regulator and related circuits.

5. Don't use fuel oil at will. It is very important to choose the same brand of oil. The choice of fuel model is also very important, so don't choose different models at will.