Stupid things the ECU does.....
 

Thought I'd put up this thread for people that are doing ECU swaps or motor swaps and using some stock ECU functions..

Here's a good one.....

If you disconnect the IAT sensor ( basically the MAF) then the generator won't function properly. the output flatlines at 13.4V and the Generator ( Battery) light comes on

I spent a couple of hours....swapping in another generator...reading the manual.....and I finally came across a line that said check to see if 0112 or 0113 DTC's were set when the Generator light came on.....so I plugged the MAF back in and it went off....and the voltage went to 14.3V and reacted normally to load...unplugged it and light came back on...and the voltage flatlined again

This is definitely fitting for this thread

lol! that is odd.

the thing that is relevant to engine swaps is what the ecu does without the wheel speed input.

I've found that on several Mazda's. For some reason Mazda wants to use the IAT reading as a measuring stick to even consider charging the battery.

Even more odd is when the battery is in the trunk and the car is factory turbocharged. Huge disconnect in the actual environmental conditions.