In the e85 thread, I asked bob about these timing oscillations:



His response:


ZUE says:



And MDZW is:



comments?

Apologies, but my german is terrible..

Let me try

The values in DMAUFN are set such that for all RPMs, there is a slope of 5%/sec?

Bob, thanks for the info. This isn't for a current car; this is just behavior i've seen in many, many other cars that nobody has ever been able to explain (across many forums). If I see it again, I will log.

Out of curiosity, what was the fix? Reduce MAF readings (via MLHFM or KFKHFM)? or something else? Also, what do you mean by full load?

I haven't had this problem on my S4, but I have seen this on other cars I have calibrated.
General fix is that the actual values meet the requested and not to allow ignition interventions in that situations 

To describe the situation in a few words:

The ECU has a driver requested torque value it wants to meet. It sets a torque setpoint for the slow (air) and fast (ignition) path. If air is too much, because of poor boost control calibration for example, the ECU tries to reduce torque on a other way (ignition angle) if it's allowed to. But these interventions through ignition angle are liked to certain enable conditions (BBMDEIN).

The key to understand what the ECU is doing, is to understand the torque structure.
Start from section MSF in the Funktionsrahmen and elaborate from there.
As I've said I will do a short write up as well.

I know how frustrating it is to explain the *general* case w/o discussing a specific problem/log, but please bear with me! I appreciate your help.


I.E. large neg deviation? (req<actual ps)

What about incorrect MAF calibration (e.g. MAF readings higher than actual air)?


Got it. Question is, what rules of thumb do you follow when you decide when to fix the REASON for the intervention, or whether or not to allow intervention. Again, I realize this is a general question, but bear with me


Got it. I have been trying to, but my German (especially technical) isn't so hot, so you'll have to be patient if I ask very dumb questions.


Thanks in advance

Keep in mind my goal is to continue to elaborate on the s4 tuning wiki page, which is far too simplistic and is missing many many important troubleshooting tips. So I would also appreciate some honest criticism of that information. I know a lot (most?) of it is probably misleading or incorrect, but I am committed to making it right, since it is the only single, open, easily accessible place that i know of for a top level summary of the most critical maps.

By off, do you mean higher, or lower.

Seems to me requested is almost always below opt... or should be?

Yea, it seems to be "rate of change" related, either to MAF or RPM

Why not to test it?
Just reset both to stock values...