So I had a Apexi PFC hooked up, the car is single turbo so a lot of the stock sensors are deleted, i took the PFC off to hook up a Haltech platinum Sprint RE.

Well i hooked the stock ECU (N3A1) in order to move the car really quick, while the car was running, it sounded like a bridgeport, even though the car is stock motor. then i smelled something electric burning, look to my right and see a little smoke coming out of my ECU. took it off and opened up and this is what burned.

I am afraid of buying another one and burn it too. what could cause this? here i circled what burned.

 

Loose ground or power wire

 

when you delete those wires , and sensors if you dont cap them off so they dont ground out . thats what happens

 

the battery is relocated in the trunk, and since i was moving it really quick the power terminal was snug on the battery tight but not bolted down. I was also getting a faulty OMP code before, and i was reading that a faulty OMP can take a ECU down. thinking about blocking the OMP since i premix already anyways.

 

when i deleted the sensors they were capped off. thanks though

 

If you look at the yellow terminal plug strip on the front of the ECU, can you see any damage/heating/discoloration/etc to any of the plug pins?

If so, it's a matter of finding out what the pins are for, using the ECU pinout diagram and chasing that circuit in the car.

If no clues on the pins..... Dunno. Find someone here who has experience in the ECU internals, and can tell you what that burnt area is for.

Actually, if you search something like "Motorola ECU" in the 3rd Gen forum area, you will stumble onto some posts from some very bright guys who were attempting to pull apart and reverse engineer the factory ECU. PM one of them. They could probably help you.
*Because the stock ECU chipsets were manufactured for Mazda by Motorola, and it was mentioned in the titles of the threads you should search for*

 

out of ideas then LOL

 

It had to be a faulty OMP, I got a different one from ebay, disconnected the OMP plug, plugged the ecu, started the car and nothing burned...