I heard that the DC2R black key is linked up to the DC2R ECU in someway that if the ECU was changed, the car won't start. If that is true, then how come when i put a OBD1 ECU into my car, it starts no problems?

Wouldnt the key send a signal to the control unit, and then the control unit would send a signal to the ECU that must match to start the car? So because the OBD1 ECU has no immoboliser start, it would not be able to recive a signal thus not starting the car?

 

The ECU, not the IGNITION is what determines if the car starts with the immobilizer system on the dc2r.

An obd1 ecu doesn't have an immobilizer.
The obd2 ecu looks for the immobilizer circuit to complete before starting...

 

But still, since there is no immoboloser with the obd1 ecu, the circuit cant complete so it wont be able to start? Or does the circuit just not exist with an obd1ecu?

 

the circuit is not there in obd1.