Stage 2, knock at low load, need an advise.

[merchgod]

Great explanation, thank you, guys! I do see some FLCK here and there, but usually it gets cleared after each 15-20 min drive.

BTW, if IAM was lowered, how fast it can be restored? Usually I did not log IAM, just cheking it in LeraningView after each logging session. It was always 1. Could it be lowered during a run, and then restored to 1 again, before I check it in LV?

Yes it is possible. You are lucky in that you can log knock sum - not all ECUs have this feature. I wouldn't even bother logging FBKC, FLKC, IAM - just check a learning view before and after the run and log knock sum. Or if you do want to log those and your ECU supports the engineer's logging parameters, then log the 1-byte versions.

[lepich]

then log the 1-byte versions

- To produce log with more resolution?

I do have 1 bit versions.

[merchgod]

- To produce log with more resolution?

I do have 1 bit versions.

Yes, you want to log the 1-byte versions if available unless you need the additional precision of the 4-byte parameters - which really isn't necessary with FBKC/FLKC as long as you realize the value represented is not going to exactly match the decrements/increments in the ROM editors (IIRC, 0.5 degrees steps for 1-byte FBKC/FLKC). You should always log IAM 1-byte regardless as the should be no difference in the value between that and the 4-byte version. Really, I would log only the knock sum and do a learning view before and after which will be adequate in most cases for tuning.

[black318i]

What is the difference between all of the byte versions?

[merchgod]

What is the difference between all of the byte versions?

4-byte versions have the highest precision - they represent the value exactly as used by the ECU (In fact, you are logging the exact address as used by the ECU). 1-byte/2-byte parameters are based on the original 4-byte parameter, but the ECU performs a narrowing conversion to reduce overhead and therefore improve the overall logging speed. The disadvantage is that there is less precision and in some cases, it results in a min or max limit even though the 4-byte parameter has no effective limit (that is not really a concern for engineer parameters (**) for turbo models except for Engine Load 2-byte/1-byte which will be limited to 4.0 g/rev).