I don't have a diesel but I drive one at work. I can bring air pressure up from 0-120 in less than 3 minutes and we take off with engines cold. I don't see a warm up for that long. we are also not aloud to idle for more than five minutes or we will be written up for excessive idle. The good old GPS system warns them and it works pretty good, they got me for excessive idle while sitting at a stop light because of so much traffic it took me 3 lights to get through the intersection. Also there is a Calif. state law now restricting excessive idle. Some people are just down right rude.