If the engine is cold, the car will shake. What happened?

The possible causes of serious engine cold-start jitter are: engine mechanical failure, such as uneven pressure in each cylinder; Air intake system failure: such as excessive dirt in the air intake pipe; Engine management system failure: such as incorrect coolant temperature and intake air temperature signals, line failure, etc. Ignition system failure: such as excessive carbon deposition or incorrect gap of spark plug, leakage of high voltage line and distributor cover, damage of ignition coil, etc. Faults in the oil supply system: for example, the nozzle of the fuel injector is not tightly closed or blocked due to excessive colloidal carbon deposition in the nozzle.

If the engine jitter disappears with the increase of engine temperature, it may be caused by excessive carbon deposition in the spark plug, because it burns with the increase of steam intake and temperature.

How to maintain the car engine?

1. Use qualified coolant (antifreeze).

It is very important that the automobile engine needs to rely on the water tank to cool down, otherwise the engine will easily "boil" and cause fatal damage to the engine. Therefore, it is usually necessary to keep the coolant in the water tank at a normal level, and choose a good quality coolant, especially in winter, and choose a suitable coolant according to the ambient temperature. In the normal maintenance of automobiles, engine antifreeze needs to be replaced every year.

2. Regularly clean water tank scale, etc.

Rusting and scaling of engine water tank are easy problems. Rust and scale will restrict the flow of coolant in the cooling system, reduce heat dissipation, lead to overheating of the engine and even cause engine damage. Therefore, in daily maintenance, we should choose the appropriate coolant ratio according to the specific situation. And when adding coolant, it can be between the maximum value and the minimum value.

4. Regularly remove the "carbon deposit" on the car.

In the process of burning oil, it is inevitable that there will be carbon deposition. Excessive carbon deposition will lead to abnormal phenomena such as difficult start-up, unstable idle speed, poor acceleration, sudden refueling and tempering, excessive exhaust volume and increased fuel consumption. There are many adverse effects on the engine, so we should pay attention to prevent carbon deposition, drive at high speed as far as possible, increase the speed appropriately when shifting gears, avoid idling for a long time, and use clean gasoline. And maintain good driving habits to reduce carbon deposition. If there is a lot of carbon deposit, you should go to the repair shop to remove the carbon deposit.

5. Replace the car "three filters" on time.

Three filters refer to air filters, oil filters and gasoline filters. The three filters play a role in filtering air, engine oil and gasoline on the automobile engine, thus protecting the engine and improving its working efficiency. Therefore, in order to keep the engine in the best condition, it is necessary to replace the filter element in time, or replace the filter element when it is dirty.

6. Keep a reasonable speed

When the car is running normally, a reasonable speed can make the engine run normally. However, if it runs at low speed or high speed for a long time, the engine will be overloaded, which will not only consume more fuel, but also easily hurt the engine. Therefore, when driving normally, the speed should be well matched with the gear, and the accelerator should be lightly stepped on, not slammed.