99 Suburban loud popping sound smoke

Twice my 1999 Suburban (approx 112,000) has made loud popping sounds when I turn it on. Both times the truck did not start. The first time I heard it, I did not know when it came from. The second time I heard it, there was smoke coming from under my hood. The smoke was coming from under the drivers side. I have know I idea what was smoking. However, both times the suburban started up when I turned the key. I am not sure if something short circuited, because everything seem to be working well on the truck.