AFR goes rich, ONLY on right turns

So, my afr goes 10 only on right turns during my car's first testing on race track. Nothing at braking, acceleration or left turning.

I have replace the coils, disable the knock sensor from the engine full up the gas tank but still get the same result.

its an Evo2 , 4g63 engine.

Aem ems4 ecu

Other to consider, i have just notice that the voltage output of my alternator when the engine is at idle is 15,6v. Also the battery has the same 15,6. When the ignition button is off the battery's voltage is 13v (think because is brand new and its been charged at 90-95%. The previous one was died at the track during those rich afr and also had a 15.6v ) . I think the alternator needs a rebuild.

I also running a custom fuel setup with a surge tank.

Didn't read the log file yet.

Why only at right turns?Any one experience something similar?

Only guessing but sensor input is going to ground on wideband if 0-5V signal (if not digital) for a phantom rich or fuel return port in tank is going under fuel level and generating a bit more back pressure in the fuel system causing a genuine richening. Any reports of soot from other drivers?