Belt not broke, engine wouldn't even start then. It CAN run quite well until you hit a certain higher rpm then go completely to crap if the belt has stripped teeth and jumped time slightly. I've seen perfect idle with belt off two teeth.
Don't mess with the converter, they absolutely do not simply go away all at once unless you hit something and shatter the internal ceramic brick. Virtually impossible on vertical ones like these.
Pull top cam sprocket cover and look at backside of belt, if you've seized an idler pulley to jump belt there will be some sort of scarring on belt backside. You can check for missing/stripped teeth then too.
Motor is non-interference.
Smell from rich condition since cam timing so retarded, the rich blast hitting a normal converter can do it.