I think it is very likely that there is a significant problem with the ripped up Z32 ECU. That whole approach is so substandard these days that you should just abandon it unless you have the gear required to try to work out what it is doing. (Which is fairly basic workshop gear, a wideband, decent timing light and/or CRO, etc. Hell, if it was properly Nistuned, at least you could look at it in software.)
Bin it. Put in some modern injectors that are big enough to be useful (like, EV14 based 1000cc from a reputable source), and start again.