Celica Forums News Portal r/Celica Need some help with 5th gen running too rich. [r/Celica]

I have a 1990 St184R 5th gen thats gotten a 1993 engine replacement due to damage caused by previous overheating on the og engine. After it was swapped by an experienced old man mechanic; who kept the og intake manifold, valve cover, ecu and harness, the engine has run very very rich, once warmed up, it gets very black and carbon soot goes everywhere. I changed a faulty o2 sensor on the exhaust, I've replaced an absolutely destroyed catalytic converter and exhaust bits, and now the car is at another mechanic with cleaned injectors and replaced spark plugs. Still smoking dementors out the back. He's brought to my attention a broken egr unit (which I've been told its better off just gone) a disconnected maps sensor (reconnected) and a bunch of harness wires coming off the sensor plugs shown on the videos below. Any parts advice, experienced suggestion or help would be great.