Non start

I smashed a back window and dented all the passenger side on
My 99 t reg jimny and it was rusty as hell, so i fit my spare complete
Body off a 52 reg jimny last weekend, it was complete inside but the loom in the engine bay
Was different, so i swapped that and fit the old ecu aswell tryed starting yesterday
And it just turned over but didnt start.
Check spark plugs and they were dry and not sparking.and the engine light is flashing
I suspect i will have to change the in car wiring loom but i wanted to keep
That as it has central locking on the button and its abit more work.

Just wanted to know if there was any way round this ? Could it be a engine fault?
Any advise would be great..
Mike.

The engine is immobilised.

Did you fit the immobiliser that matches your ecu, AND change the lock barrel so the matching key goes in the ignition?

I believe the ecu and immobiliser unit and its ignition key are all a matched set.

Is that why the engine light is flashing ???
The immobiliser unit on the 99 jimny is a seperate unit, from what i can make out and the 52 one is on the antenner ring, is this correct, is so i will have to swap loom.
Also was just gonna swap key chips so i still had central locking and of course the wiring.

There is an immobiliser unit, and an antenna surrounding the ignition lock, this shouldn't be coded.

The flashing light means the engine is immobilised because the key code and immobiliser code don't match the ecu.

Yer i understand that the antenner ring is just a sensornto pick up the code.
But on the 02 jimny it is part of the antenner ring and the conntion and amount of
Wires is different. So i started swapping the wiring loom last night.
Thanks for your help.