Will replacing the immobilser unit, ignition barrel and key be enough to get my Felicia started, or is it necessary to replace the ecu as well?

I have shorted out the old sensor unit attached to the old barrel. Will this have permanently damaged the immobiliser unit, ecu?

Would appreciate any experieces/expertise in this area.

The immobiliser box is coded to the ECU - replacing one and not the other won't work. Have you tried replacing the sensor ring? AFAIK they aren't coded, so you could try changing that and see if it works.... Certainly be easier than changing the ECU and immobiliser box, and recoding keys (taking the glass bits out, etc)....

Haven't tried what you've suggested - think I may have damaged the immobiliser box by shorting out the the sensor connections but will certainly try replacing just the sensor - Thanks