What Are the Causes of Black Smoke from Diesel Vehicles?

1 Answers
LoganAnn
07/29/25 5:02pm
Here are the reasons why diesel engines emit black smoke: 1. Fuel supply system factors: 1.1 Fuel injector: Fuel injector dripping, poor atomization, or insufficient injection pressure; 1.2 Fuel injection pump: Wear of the fuel injection pump plunger or delivery valve, insufficient common rail pressure, or excessive fuel supply; 1.3 Injection timing: Incorrect injection advance angle. 2. Combustion system factors: 2.1 Valve clearance: Incorrect valve clearance; 2.2 Piston rings and cylinder liner: Severe wear of piston rings and cylinder liner, leading to insufficient compression pressure; 2.3 Piston top clearance: Improper adjustment of piston top clearance, resulting in too low compression ratio. More related information is as follows: Notes: Black smoke from direct-injection diesel engines cannot be completely avoided. However, if the engine emits thick black smoke under normal load without overload, it is abnormal and requires further inspection.
Was this review help?
14
2
Share
More Forum Discussions

What is Cylinder Pressure?

Cylinder pressure refers to the magnitude of compression force when the piston reaches the top dead center at the end of the compression stroke. Insufficient cylinder pressure indicates reduced cylinder sealing, which will lead to decreased engine power, difficulty in starting, and unstable engine operation if individual cylinders lack sufficient pressure. For gasoline engines, the cylinder pressure typically ranges from 8 to 11 bar, while for diesel engines, it ranges from 12 to 16 bar. Specific values should be referenced according to the manual. Methods for checking the cylinder compression pressure of a gasoline engine: 1. The engine temperature should be between 80-90°C, and the battery discharge level should not be below 50%. 2. Remove all spark plugs and fully open the throttle and choke valves of the carburetor. 3. Press the rubber head of the cylinder pressure gauge firmly into the spark plug hole of the cylinder to be tested and hold it in place. 4. Use the starter to rotate the crankshaft for 3-5 seconds at a speed of 150-180 rpm, and record the pressure value indicated by the gauge. Repeat the measurement twice and check the remaining cylinders in sequence. 5. If the cylinder pressure is below the specified value, add 20-30g of fresh engine oil to the top of the piston and recheck the pressure. If the pressure rises significantly, it indicates severe wear of the piston rings and cylinder. If the pressure remains the same as before, it suggests air leakage at the valves or cylinder gasket, and further inspection is required.
8
2
Share

What are the procedures for obtaining temporary license plates for a new car?

To apply for temporary license plates for a vehicle, you need to bring the car purchase invoice and the motor vehicle product qualification certificate. After the vehicle passes the inspection by the public security vehicle management department, temporary license plates will be issued. These are paper motor vehicle license plates that allow temporary road use, also known as temporary driving license plates. They serve as temporary vehicle driving permits issued by the public security vehicle management department before the new vehicle is officially registered. The use of temporary license plates is subject to time and regional limitations. You can apply for temporary license plates from the local vehicle management office under any of the following conditions: 1. When driving the vehicle from the place of purchase back to the place of use, you need to apply for temporary license plates at the vehicle management office where the car was purchased; 2. If the vehicle is being transferred and the official license plates have already been surrendered, you need to apply for temporary license plates at the local vehicle management office to drive the vehicle back to your locality. The vehicle management office will review the above documents to ensure compliance with regulations and conduct a safety and technical performance inspection of the vehicle. If everything is in order, temporary driving license plates will be issued, specifying the validity period and the start and end locations.
11
0
Share

Solutions for Highway Tire Blowouts

The following are solutions for highway tire blowouts: 1. Keep both hands on the steering wheel at all times and avoid turning the wheel. 2. Do not brake immediately and forcefully after a blowout occurs. 3. Turn on the hazard lights and immediately resume holding the steering wheel firmly. 4. Observing the rearview mirror is crucial. 5. On highways, only apply brakes to slow down when the speed drops below 100 km/h after a blowout. Here are additional tips to prevent tire blowouts: 1. Conduct pre-trip inspections; 2. Install a tire pressure monitoring system; 3. Apply a protective coating to the inner wall of the tires; 4. Rotate tires regularly; 5. Regularly adjust wheel balance.
10
1
Share

How to Control Car Windows with the Key Fob?

Here are the methods to control car windows with the key fob: 1. Generally, a car key fob has several buttons, including door lock, door unlock, and trunk unlock. 2. Regarding remote window control, it is usually combined with the door lock/unlock function. 3. Press and hold the door lock button—with the doors locked, the windows can be remotely raised. 4. Press and hold the door unlock button—with the doors unlocked, the windows can be remotely lowered. Additional Information: 1. The unlock button, as the name suggests, unlocks the car with a single press. As a complementary type to infrared remotes, car key fobs are widely used in remote control and anti-theft systems for electric vehicles and cars. 2. The transmitter part is generally divided into two types: remote control units and transmitter modules. Remote control units can be used independently as a complete device, with external wiring terminals, while transmitter modules are used as components in circuits, applied according to their pin definitions. The advantage of using transmitter modules lies in seamless integration with application circuits, compact size, lower cost, and efficient use of resources. However, users must have a solid understanding of circuit principles; otherwise, using a remote control unit is more convenient. The receiver part is also typically divided into two types: superheterodyne and super-regenerative reception methods. The super-regenerative demodulation circuit, also known as the super-regenerative detection circuit, essentially operates as a regenerative detection circuit in intermittent oscillation mode.
11
4
Share

How to Read Tire Model Specifications?

Here is an introduction on how to read tire specifications: 1. The numbers are in millimeters, representing the section width and the aspect ratio as a percentage. This is followed by: the tire type code, rim diameter (in inches), load index (permissible load capacity code), and permissible speed code. 2. For example, if the tire specification is 195/55/R16-85V. 195 refers to the tire width of 195mm; 55 refers to the aspect ratio, meaning the section height is 55% of the width; R indicates that the tire is a radial tire (the inner layer of this tire is made using the radial tire manufacturing method); 15 refers to the rim diameter of 15 inches; 85 refers to the load index, where 85 represents a maximum load capacity of 515 kg, and four tires would be 515×4=2060 kg; V indicates a speed rating of 240 km/h.
12
5
Share

Can a Two-Wheel Drive Converted to Four-Wheel Drive Pass the Annual Inspection?

Converting a two-wheel drive vehicle to four-wheel drive will not pass the annual inspection. The vehicle's drive configuration is recorded in its official records, and altering it to four-wheel drive changes the vehicle's original drive form, thus failing the inspection. Below is additional information on converting a car to four-wheel drive: 1. Converting front-wheel drive to four-wheel drive requires modifying the rear axle, installing a rear differential, adding a driveshaft, etc. This type of modification is highly technical and poses significant safety risks post-conversion. 2. Converting rear-wheel drive to four-wheel drive involves replacing the transmission, installing a transfer case, adding a front differential, and installing a driveshaft, among other changes. 3. It is advised not to casually alter a vehicle's drive configuration. Additionally, during the annual inspection, modifications to the vehicle's exterior or lighting system will also result in failure to pass the inspection.
19
1
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.