Elpecoso

I have a 93 honda eg with a b20b4 block & b18b1 head swap(non vtech)(got a good deal out of both so i put it on the eg) little more info into this. I kept my single cam harness from d15b7 & bought the adapters for the distributor, alternador & ecu to use with the harness. My ecu is a virgin p75-a03 from a 96 integra. When I turn my car on after a minute or so it loses power close to turning off or at times it completely dies. My question is having this engine setup, was I supposed to chip & tune my ecu? Could that be the problem?... I did a vacuum leak check around too & found out the intake manifold & throttle body gasket were bad so I replaced them, but still nothing... Any help or suggestions?????