Timing Question??????

[bustiegtr]

I recently did the s13 swap in a 1991 hardbody pickup, the truck starts now but idles like crap. A/F gauge is bouncing up and down in the lean and its blowing out some ugly black smoke. I know the idle being off is due to the timing but would it cause it to blow this smoke. Oil is good as well as the coolant all levels are up. Could my MAFS be bad? Also I got the megan racing turbo elbow and it required the fat O2 sensor and some people told me the 1992 sentra ser would work, is this so? Its a 3 wire (Red, black, and white) now correct me if i am wrong red (power), white (to the ECU), and black (ground)? Any help is appreciated, I need this truck back on the road.