Hello, I/M refers to Inspection and Maintenance. This is a video I made to introduce how to upgrade the AL500: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-t9GXzr_TwUU.html , if you are interested, you can watch it or give your opinion. There are more videos on my homepage of using related products to perform functions, you are welcome to follow my account. thanks.
As far as I know: Petrol cars have throttle body because engine is controlled by quantity of the fuel-air mixture. Throttle body closes and open to control RPM, air/fuel ratio stays the same (most of the time, to simplify). Diesel cars don't have throttle body, because engine is controlled by quality of the mixture. RPM is controlled by how much fuel is added to the mixture, air/fuel ratio is changed based on the RPM demand. At idle diesel will show intake pressure close to atmospheric pressure. If there's a throttle body in diesel engine, it's for variable intake (some kind of swirl flaps or intercooler bypass in HDI engines) or it's a shutoff valve.
