hello, does anyone here have any experience with the 7.8 duramax? It's a 03 c6500 roll back. The guy I'm helping said they fired it up ran down the road and it just died and wouldn't restart, I stopped today to take a look at it and it turns over but will not fire there is fuel up to the injector lines and while cranking there is smoke from the exhaust. Unfortunately I don't have a medium duty scanner to check codes. Anyone have any ideas?