wrong engine for auto????

hi to all. contrary to my avatar, i now have a 300tdi auto it was registered in 1994 so its one of the earliest 300 series when i purchased the car it was painfully slow so i followed the tutorials on this forum to adjust the injector pump with marvellous results however on doing a little more reading i found that most info relating to the 300 auto states that the pump is electronically controlled by an ecu this was further confirmed by my boss purchasing a disco that was registered only 6 months later than mine and low and behold its got an electronic injector pump. my pump is definately the mechanical type and looking at my bosses the difference is blatantly obvious. His is like driving a completely different type of vehicle compared to mine it revs very quickly and freely compared to the slow steady pick up of mine. his power delivery is far smoother and more refined and consequently his autobox changes seem quicker and more precise.. So does anyone know if the early 300 tdi auto had the mechanical pump or does it sound like the engine from a manual may have been transplanted in at some point. If an engine change seems the likely conclusion where is the ecu situated so i can see if its still there and would it be possible to refit an electronic pump to the current engine? The fuel consumption of the car was bad before i tweaked the fuelling, i didn't go mad with the tweak but did just enough to make it usable in everyday traffic however i'm now averaging only 17 mpg round town with no more than 20mpg on a run. this further leaves me to believe that the engine is mean't to be in a manual and can't cope with the demands of an automatic.. any advice would be greatly appreciated