Originally Posted by DieselAddict

Diesel engines still consume considerable amounts of fuel when idling. Ever done a diesel purge? You are correct that the newer engines with DI usually don't need a glow, but I'm not aware of any heat element in the intake. They do have glow plugs which at least on the TDI become useful when starting the engine cold at 45F or below. Above that the air in a DI engine is warm enough to cause the fuel to ignite because unlike in an IDI engine there are no prechambers that soak up the heat.