I tried to connect my P28 ECU which was chipped with a skunk2 program but rite now has a factory GSR program.
Im using an OBD2 to OBD1 harness that I bought from KS-Motorsports I made sure everyting is plugged in properly but I coulnd't get it to turn on it cranked but thats about it

any suggestions this is on a 99 ITR btw

 

If it turns over but won't start, then you should be getting an engine light. Check what it is. Otherwise, if no light, it's either ignition or fuel (no fuel, fuel pump not coming on, no signal to injectors, no spark, bad signal coming from ECU, ECU harness not wired correctly or ends came loose). That should give you some ideas of what to check for.