docslide

So i am right at the tail end of my swap.
The Car was a Dohc car to start with and ran great until the engine spun a rod.
Decided to park the car and drop an sr in it.
I finally get it all together and go to fire it up. Well my first ecu was a PowerFc. Turns out it didnt work on any car. So then i went out an bought a rom tuned ecu. get home with it tonight and go to turn the car on. It first thing i noticed is that the little red ecu light wasnt turning off. Switched out the ecu relay and that fixed that problem. i cranked the car over a couple times and looked over and noticed that my ecu was smoking.Now im assed out with a fried ecu.
Im thinking there is something wrong with my engine harness but could the chassis harness have anything to do with this?
I could really use some help on this. Thanks.