Petbeemer

Ok so ive swapped engines from my original wrx bugeye to a jdm sti engine from a bugeye, ive used the inlet and inlet loom from the sti and pin swapped the different connectors on the right hand side black plug and added the extra cam angle sensor wires and run them direct to the ecu from the left side, plugged ecu in and...... nothing!
Engine turns over but no sign of life, taken the fuel line off and no fuel is present so im presuming it's an immobiliser problem cutting the pump

Question: How does the stock immobiliser work on the bug, is it in built to the ecu? but if so i thought jdm cars didn't have the immobiliser fitted?

My key is still original and still open/locks doors via the buttons on it, flashin key on dash is still working

Any ideas how to work around this?