When asking for help, please provide more information about your problem, like what was happening before, and what entity you placed. That way, people don't have to guess when trying to give you a solution.
I'm going to assume you were using ABS's pack since you apparently aren't used to seeing the HL2 spawn model. The correct spawn entity to use in TF2 is info_player_teamspawn (not info_player_start, which shares the same HL2 model). info_player_teamspawn will work whether it looks like the Engineer or not. If it suddenly stopped looking like an Engineer, you may have to reinstall ABS's pack.