I just put a b16a2 in my 92 vx civic, and the exaust is kinda black. And there is a lot of fumes. So i think that the car is running rich. It is a jdm motor and a friend of mine thinks that mabey the jdm ecu is set like that. i am getting about 16-18 miles per gallon, so i am hoping that better tunning can solve this problem. Do you guys have any idea where i can start.

 

have you upgraded the fuel pump?... check the fuel pressure regulator

 

Running stock ECU or a chipped one? Skunk2 & Mugen chips are notorious for uber-rich fuel maps.

 

any engine lights? did you have the O2 hooked up.