What kind of things would one see if the ecu is no good?(besides not starting)

 

A wrong ECU (faulty too i think?) would be shown by a blinking check engine light, but im not 100% sure on that, that may be caused by too many malfunction codes at once. Happened to me on a swap upon first start.

 

A faulty PCM will do all kinds of random crazy stuff, just about any problem a car could have would happen because of this, but very randomly. Expect random multiple CEL's for no reason, poor fuel mileage/misfire/knock (if the car runs at all). You could also have a fire in there. But most of today's PCM's have no reason to fail, that was a long time ago and electronics are much better. When you mess with them is when you risk trouble.

If you burned up some transistors in there it would smell aweful, like burned electronics do.