Possible Bad ECU

[94H_Ex]

My Cb7 (1990 Honda Accord Ex) is running rich. It was running rich with the engine I had orignialy in it. When my brother took over it, they bought a whole new engine, and didn't take any of the sensors off the old block. So there was two different sets of injectors and sensors in the same car and it's still running rich.

My question here is:
Has anyone came across a ecu that makes a engine run rich just from simply being old and or malfunctioning?

I realize since I haven't owned this car from brand new there is possibly a re-mapped ecu in it. To what specs only god will know.

 

[egb19c]

What are using to check air/fuel ratio to verify that it's running rich? Do you smell unburnt fuel? Do you have a wideband?

 

[94H_Ex]

Decent amount of black smoke, and the smell of unburnt fuel from the exhaust.

 

[RoughKnight]

spark plugs/wires/air filter/fuel filter

other than that, if the new motor wasn't the same as the old one, there would be some complications