Oil stains on the outside of the throttle?

There is oil in the automobile throttle because the exhaust gas of the engine is recirculated and discharged into the air intake. Throttle is an important part of EFI automobile engine system. Its upper part is air filter, and the lower part is engine block, which is the throat of automobile engine. Failure to clean the throttle for a long time will lead to an error in the throttle opening, and air with impurities will enter the combustion chamber of the engine, resulting in abnormal operation of the engine. The traditional throttle valve is that the accelerator pedal is directly connected with the opening of the throttle valve through steel wire or connecting rod, so as to control the air intake and fuel injection. Electronic throttle is composed of engine, speed sensor, throttle, etc. Electronic throttle control system can accurately control the throttle opening.