I've just bought the ECU off of a 92/93 130PS XR3i (2FBC)
I've just fitted it to my 97/98 115PS Escort Si and when I reconnected battery and tried to fire it up - I heard no fuel pump activity, and the engine didn't crank.

(Was like the battery wasn't connected)

Any ideas? Anything to do with PATS? Haynes manual said it would crank but not fire if PATS was active - but it isn't cranking either

I've checked all fuses are ok, and that the ecu is firmly connected to the harness.