I have a 94' Honda Civic DX and it currently has the P06 ECU but the engine is from a 97' Honda Civic Del Sol Si, It has a the CEL on and its giving me a Code 43 and I read on another Forum that the wrong ECU can cause the car to run rich and have lots of carbon out the tailpipe. I'm not sure if there is a certain conversion adapter on the car. I did some research and believe I may need a P28 ECU but I'm not 100% sure.

 

The P28 ECU is the simple answer and it should run that engine nearly perfectly.