Runnig Rich, black smoke out of ideas

[anti_flag_army]

Hey guys, I have been trying to diagnose my friends issue since yesterday, and i have tried everything i could find on the issue. I started with basic tune up items, plugs, wires, cap, rotor, o2 sensor. Cleaned the MAF. None of that made a difference. I then took off the IACV and cleaned it really well and the idle became rock solid unlike ever before. So then I set the idle and timing. Still blows black smoke.

Today I adjusted the TPS to .45 volts, found a torn vacuum line at the FPR, still didnt fix it. I then Swapped the FPR and Injectors with ones I had in my garage and still the same issue. I dont know where to look next! We were hoping to try to smog it today, but at this rate i dont know if we will get there. The car is an 89 with a single cam all stock.

[compactfean]

Coolant temp Sensor.

[anti_flag_army]

That was the first thing I tried when it started since that was the issue we had on another 240 a while back, no dice.

[ls1240]

Ave you tried adjusting the timing? Or o2 sensor?

[anti_flag_army]

Yep mentioned both of those in the OP

[compactfean]

What is fuel pressure and what is maf voltage?

[nissan2.4]

Yeah i would do a fuel pressure test, ur injector o rings could be bleeding by causing it to run rich, after checking timing and everything else u might wanna do a compression test, might have an internal problem like burned exhaust valve.