Dongfeng Nissan Qi Jun cold car idling at high and low.

Cold start jitter is mostly caused by poor fuel combustion. There is too much colloidal water in the fuel tank. The cold start is not taken to the combustion chamber, then mixed in the fuel tank and pumped into the combustion chamber. Jitter caused by poor combustion.

Engine jitter has the following reasons:

1, the engine has serious carbon deposits, and the most common car with serious jitter is that the fuel injector throttle is too dirty or has too much carbon deposits;

2, ignition system problems, check the working conditions of spark plugs, high-voltage lines and ignition coils;

3. The oil pressure is unstable. If the supply pressure of the pump is abnormal or the intake pressure sensor is wrong or not working well, the body will shake;

4, engine parts aging; Excessive carbon deposition in engine exhaust will adsorb carbon in gasoline of cold-start injector, which will lead to too thin cold-start mixture and difficult starting.

Specific solutions to idle jitter:

1, engine carbon deposit is serious. The most common cause of idle jitter is excessive carbon deposition in throttle or injector. When there is too much carbon deposit in the engine, the gasoline sprayed by the fuel nozzle will be absorbed by the carbon deposit during cold start, which leads to too thin mixture and difficult start. In this case, it is easy to hit the car only if the gasoline absorbed by carbon deposits reaches saturation.

After landing, the gasoline adsorbed on the carbon deposit will be sucked into the cylinder by the engine and burned, and the mixture will become thicker. When the mixture is thin and thick, it will cause idling jitter after cold start. The lower the air temperature, the greater the amount of oil required for cold start, and the greater the influence of carbon deposition on cold start. The solution is to clean up the carbon deposit on the throttle and the fuel nozzle.

2. The ignition system does not work well, and the ignition condition of the spark plug is not good, which will also lead to engine idling jitter. If there is a problem, check whether there is a fault in the ignition system and whether there is too much carbon deposit in the spark plug.

3. The oil pressure is unstable. If the engine carbon deposit has been cleaned, the throttle has been cleaned, or the spark plug has been replaced, there is still the problem of idle jitter. It is recommended to go to 4S shop to check whether the fuel supply pressure and intake pressure sensors are normal. If the oil supply pressure of the oil pump is abnormal or the value of the intake pressure sensor is wrong, it will also cause the problem of idle jitter.

Solutions;

The best way is to clean the oil circuit and clean it regularly. There is no specific experience in engine development parameters from new cars. In addition, with the continuous improvement of emission standards, it can not adapt to the changes of fuel. It is impossible for all engine manufacturers to solve this jitter problem in a short time. In addition, the fuel quality is not very good or the fuel storage time is too long at the beginning of the new car, which leads to the rapid increase of colloidal components in the oil circuit, which will continuously pollute the fresh fuel, resulting in no good fuel to participate in the combustion in the later stage, resulting in excessive carbon deposition. Only by maintaining a clean oil circuit can most problems be gradually alleviated. Using fuel additives such as PNF stock solution can solve the above problems caused by carbon deposition.