Mercedes-Benz s350 dithers at idle speed and makes a lot of noise.

Cold start jitter is mostly caused by poor fuel combustion. There is too much colloidal water in the fuel tank and too much carbon in the engine. 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. During cold start, the gasoline sprayed by the fuel injection head will be absorbed by a large amount of carbon deposits, which will lead to too thin mixture during cold start and make the start shake.

If there is carbon deposit in the valve and intake of the engine, ECU will make a wrong judgment, because carbon deposit can absorb a proper amount of fuel. If the computer actually controls the injection of 100 parts of oil and gas, but only 90 parts actually enter the cylinder (10 parts are absorbed by carbon deposits), then even if the remaining 90 parts of mixed oil and gas are fully burned, the required power cannot be achieved, and the jitter phenomenon is inevitable.

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.