Audi a7 cold car whines in winter. What is the cause of Audi engine vibration?

1, cylinder depression: the engine has 3 cylinders, 4 cylinders, 5 cylinders, 6 cylinders and 8 cylinders. If a cylinder doesn't work well, there will be cylinder missing and engine jitter. Three-cylinder engine is the most obvious, followed by four cylinders. Check the cylinder pressure with the cylinder pressure gauge and solve the problem of low pressure with the first bus. First Bus has a unique effect on cylinder depression and imbalance. It can be added to engine oil or directly to the cylinder to restore the cylinder pressure balance.

2. Carbon deposit and oil dirt blockage: Throttle, idle valve and air intake will be blocked by carbon deposit and oil dirt after a period of use, which will affect the idle stability and cause jitter. It can be solved by checking and cleaning the above parts with cleaning agent without disassembly and cleaning.

3. Nozzle blockage: The nozzle of EFI vehicle is the key component of automobile fuel injection, with a long service life, reaching hundreds of thousands of kilometers. However, because there is gum in gasoline, it will block the injection hole of the nozzle, resulting in inconsistent injection quantity of each nozzle, inconsistent operation of each cylinder and engine jitter. The solution is to take it down and clean it.

4. Abnormal water temperature: The working temperature of the engine is within the normal range. When the water temperature is high, the ignition time will be early, the oil-gas mixing ratio will change, the oil viscosity will become thinner and the lubrication performance will become worse. Common fault causes include insufficient antifreeze, thermostat not turned on, fan not turning, jitter caused by inaccurate temperature control switch, etc. All the above faults can be eliminated.

5. Low idle speed: the engine idle speed value has been set in the computer. When the number of revolutions is low to a certain range, the car computer will automatically adjust. If the idle speed is too low, it is beyond the control range of the computer. Some cars have adjusting screws on the accelerator to adjust the idle speed, while others don't. This kind of car can check the idle valve, throttle, air flowmeter, vacuum sensor and adjust the ignition time (car with distributor) to improve the idle speed. Low water temperature can also lead to low idle speed, so check and replace the thermostat.

6. High-voltage line break: High-voltage line break means that the core of the high-voltage line is broken, which will affect the ignition and lead to engine jitter. You can use a multimeter to measure the resistance, and change it to a resistance that is obviously several times larger.

7. Spark plug service life: Spark plugs have a service life. After exceeding 30,000-40,000 kilometers, the ignition efficiency is obviously reduced, which may affect the ignition. This is the most common fault. Just replace all spark plugs.

8. Dirty air filter: The air filter is designed to protect the engine from wear and tear, and it is usually replaced around 10000 km. If it is not replaced in time, the engine will shake due to insufficient air intake, which can be solved by replacing the filter element.