Is it necessary to clean the throttle and nozzle when maintaining the 4S shop?

At present, the profit of vehicle sales is not big, so many 4s stores regard after-sales service as the main profit point. So now whenever we go to the 4s shop to do vehicle maintenance, we are always recommended to do various cleaning services, such as cleaning the throttle, cleaning the nozzle, cleaning the ternary and so on. In fact, most of them are unnecessary, or most of them don't have to do it so early!

Throttle and nozzle cleaning will be recommended by 4s stores of major brands, only the difference between morning and evening; For example, some 4s generally choose to recommend a cleaning service of about 20,000 kilometers. Of course, some shops with bad eating habits often advise novice riders to start various cleaning after the first insurance. In contrast, novices often love cars, and it is easier to recognize this recommendation, but it is just a waste of money and unnecessary; If you want to clean the machine, you might as well wait 40 thousand kilometers!

The first thing to say about the cleaning of the throttle is that the carbon deposit on the throttle is different from that in other parts of the engine. Most of the carbon deposits on the throttle are formed by mixing some sludge and impurities in the air, so in essence, the carbon deposits on the throttle only belong to carbon-like substances. After all, when the machine is running, the throttle temperature is not high and there is no high temperature. Where can carbon come from (the temperature on the back of the intake valve can generally reach about 300)? So there is no need to clean the throttle so early; The cleaning cycle of throttle is related to throttle position, turbine or self-priming and air quality!

We all know that the carbon deposit on the back of the intake valve is directly related to self-priming or direct injection, but the carbon deposit on the throttle valve has nothing to do with it; In fact, the growth rate of throttle carbon deposition is closely related to the position of throttle! For example, the throttle of some cars is arranged below the intake manifold, so the mixed gas containing liquid oil and gas (including gasoline and engine oil) discharged from the crankcase ventilation system will probably flow back to the vicinity of the throttle from the intake manifold under the action of gravity, and then the impurities in the air at the mixing point will produce throttle sludge!

But many models and throttles are arranged above the intake manifold. If this layout is still a naturally aspirated engine, the throttle will not be cleaned or dirty for 100,000 kilometers, because the crankcase ventilation system of the naturally aspirated engine has only one exhaust pipe, which is behind the throttle (in the intake manifold). Because the pressure in the naturally aspirated engine manifold is always negative, one exhaust pipe is enough, and the throttle is still arranged above the manifold! In this way, no matter how much oil the discharged mixture contains, it is impossible to get close to the throttle, and it is not a big problem not to clean the throttle for life (it is recommended to wash it once every 65438+ 10,000 kilometers)!

However, turbocharged engines are different. The intake manifold of turbocharged engine has two states: positive pressure and negative pressure, so there are two exhaust pipes in the crankcase of turbocharged engine, one in front of the throttle and the other in the intake manifold. When the supercharger does not work under positive pressure, the pressure in the manifold is negative and there is suction in the manifold, so the crankcase ventilation system directly discharges the mixed gas into the intake manifold; However, when the supercharging system is positive pressure and the pressure in the manifold is positive, the exhaust gas mixture will take the path in front of the throttle. In this state, no matter whether the throttle position is up or down, oil and gas (including liquid fuel) must pass through the throttle to reach the manifold, so the throttle cannot avoid an oil state! Therefore, the turbocharged car can choose to clean the throttle after 3 or 4 kilometers!

As for nozzle cleaning, it depends on the specific cycle. Generally speaking, you will study after 30,000 to 40,000 kilometers. In fact, pulling the car to a high speed regularly, running at a proper high speed for a period of time, or using some pea fuel additives appropriately (more suitable for direct injection) has a good effect on cleaning the injector; There is no need to do it in a 4s shop, the price is too expensive! As long as the engine is running, carbon deposition will increase, so carbon deposition is actually a partner who will accompany the engine for a lifetime. You don't need to be too afraid of carbon deposition, just clean it up moderately! There is no need to clean the throttle or nozzle too early, and it is not too late to study when the mileage reaches 40,000-50,000 kilometers. As for the self-priming vehicle with the throttle arranged above the manifold, it is necessary to clean the throttle only after100000 km!