Idle misunderstanding

V3 SOFTWARE
1

I have a difficult understanding on how the idle airflow has to work.

1- I struggle to understand how the airflow PID has disappear from the 1st and the 2nd log … I think I am missing a point on the map but I can’t figure out what I deleted …

2- I don’t really understand the DBW target max & min for airflow. Don’t understand the calculation from this window, and active state airflow 3d map

I set up 2% min and 8% max. So the minimum DBW position should be 2% on idle active Right ?

On the log, at 7min & 9.20min, you will see that I played with active airflow map and the DBW goes really closed (approx. 1.4% => engine nearly shutting off).

I attached the last map V156.

I am not looking for a solution, only understanding :grinning_face_with_smiling_eyes:
(This community already helped me a lot) !

Thank y’all

Test_20260307_2_Cranking_ariflow_test.emublog3 (1.8 MB)

20260613_1748_test_idle_not_working.emublog3 (745.7 KB)

BECT_EMUB_HONDA_K20_Z4_SP98_20260613_V156.emub3 (67.3 KB)

2

It’s explained in the help file within the software.

3

Hello Greg,

I red it to understand but I could find the explanation for "why DBW goes down the “DBW target min” … (as explained on my log)…

And when I calculate the DBW target from Active state Airflow in %, I don’t find the calculated value of DBW final.

4

Air flow is a percentage between the dbw target min and max so 100% air flow is dbw max on actuator settings

5

Yep, understood. It is clear on the software help.

So, how is it possible that DBW goes down by 1.4% when my min DBW target is 2% ?

image
image1641×998 70.9 KB

The airflow %age is 14%, but DBW goes to 1.4% … even if DBW target is @2.8

Maybe it is a little sensor reading error, or the DC output of DBW that is very sensitive … DBW is Ø74mm BOSCH … (too much ?)

6

If your DBW target is 2.8% and the TPS position is 1.4% it means that your DBW calibration is not perfect and the throttle cannot reach the target. It has nothing to idle control. You can make the test. In the DBW settings there is override option. You can override the DBW target and enter your value. Test diferent valuse from 1% to 4% to check if throttle hits the target.

7

That seems right.

Will give a shot :crossed_fingers: and come back to you (I already made a DBW learning when I saw this issue but nothing more).

8

It could require some manual fine tuning. Also please check if the throttle is not dirty that increase the friction in the low range.