Hondata

I got datalog from Civic 1.5 Thailand Model with stock and custom tuned.

I saw stock Air Charge (AIRC Sensor) still shown 0% event map is reach 200 kpa with stock.

In the other way, My custom tuned running with the same map value (but different rpm).
The AIRC is reach 179% already. (Both log files in attachment.)

Could you explain me how do the engine got this value ?

How do I decrease AIRC value ?

While you can datalog from a stock ECU not all sensors are supported, so the air charge % is always going to be 0%. You could upload the 'stock equivalent' for a comparison.