Yikes! I’ve hit DKA 6 hours after my pump malfunctioned without my knowledge, and this is without eating anything. I’ve heard the longest a person can live with no insulin (meaning, no external source and no residual production of their own) is about 72 hours, although I don’t know where I heard that, or if it’s accurate. I’ve never tested it, and of course don’t intend to.
I would go into DKA in a matter of hours. More than 5 hours but less than 24. Its happened before