have a 2005 wrx originall fitted with 2.0 liter turbo motor. replaced that motor with a 2007 2.5 L STI turbo. Have the correct key and ECM for new motor, which is now installed.

 

When turned on, the security alert light stays on (as does the exterior parking lights linked to the security system). The car cranks but will not start, and I cannot de-activate the security alert by using key in the door, or using remote unlock, or anything else.

 

When cranking, the engine gets fuel but no spark. the car the engine came out of was in an accident (side hit) and so impact sensors were probably set off, possibly even air bags.

 

What do you think is the likely problem? How do I reset the security module to try and :confused:put it into "normal" mode?

Did you put the whole sti body harness in? I believe there is more you will need than just the key and ecu. Try your question on http://www.nasioc.com in the conversions section.

You might have to go to the dealer and have them hook up the select monitor to register the new key...I ran into this a while ago on an 07 WRX when a kid fried his ECU and got a replacement complaining of a crank no start....As mentioned you might also want to put a posting over on NASIOC or ClubWRX..