I have just completed a conversion with a Black Cover 4age 20 valve (into 89 SX). It seems to be running very rich (black smoke on hard accel and black soot on bumper near exhaust exit).
There are no error codes on the ECU, I think I have all the vacuum lines right, has new plugs, air cleaner is ok, tried resetting ecu and I have checked the timing.
Has any got any suggestions to either isolate the problem or solve it?