There could be as you suspect a mismatch between chip and engine spec, but another thing worth checking is the phase sensor alignment, if this is just 1 tooth out it will overfuel massively belching black soot etc, then there is our old favourite the cts, coolant temp sensor, replace this anyway unless new, when these go duff as they do they mostly go silly rich, but are only around £12 for a new one.
If these two prove ok, try adjusting the fuel pressure down to see if it gets to a point it is nice an clean, most chips work with std pressure but not all so try checking the chip with the maker to see what pressure etc it needs.
tabetha