Identify the active timing path
The ignition value observed during a run reflects more than one table. Identify the applicable base timing map, the conditions selecting or blending maps, temperature and operating-state corrections, knock correction and torque intervention. Record the actual load and engine speed used to address the map.
S4Wiki’s named-map examples are useful orientation for its documented VAG software. The S4 two-position cam-timing example and its exact switching angles and stock ranges are retained under ME7.1. Verify the timing strategy of the particular ME7.5 application before assigning the same meaning to a second map.
Map roles to distinguish
| Map or signal group | Meaning in the source | Interpretation |
|---|
| KFZW / KFZW2 where fitted | Base-ignition maps selected or blended by the application | Determine the active map and its load/speed axes |
| KFZWOP / KFZWOP2 | Optimal-ignition references used by the torque/efficiency model | These have a different role from the ordinary base-timing request |
| Temperature correction maps | Adjustments associated with intake/coolant conditions and load | Inspect their active conditions and the resulting correction |
| Short-term knock correction | Immediate cylinder-related ignition correction | Correlate it with operating point, mixture and temperature |
| Long-term knock adaptation | Learned correction across defined regions | Retain adaptation state when comparing runs |
| Torque intervention | Ignition changes used to deliver a permitted torque | Timing reduction can reflect a torque constraint as well as knock |
Read knock in context
Inspect correction by cylinder where the application exposes it, alongside engine speed, load, fuel, measured mixture and intake/coolant conditions. Compare repeated, controlled observations and distinguish a transient event from a persistent pattern. A clean-looking base-timing table does not explain a correction produced elsewhere in the calculation.
The source separates the amount of retard for a recognised event, the bounds or balancing of cylinder corrections, the speed/load regions used by adaptation, and the conditions under which learned correction moves back toward advance. Those functions should be read individually. The M-box notes include the source’s correction of an older description of KRANH.
Temperature, mixture and knock-related enrichment
Temperature correction can influence both ignition and knock-related mixture request in the documented strategy. Inspect the relevant correction signals alongside requested lambda rather than treating fueling and timing as independent changes. A definition’s short description, such as “warm-up”, may not explain every condition in which a function remains active.
Keep the torque model consistent
Optimal timing and ignition efficiency participate in the torque model. Changing load axes or torque-related calibration requires checking maps that use the same axes or relationships. Use available torque-request, torque-limit and ignition-intervention signals to identify why the final timing differs from the apparent base value.
A practical review sequence
- Confirm the actual operating point and active base map.
- Check the delivered mixture, relevant temperatures and hardware state.
- Separate knock correction from temperature and torque intervention.
- Review the learned adaptation state and repeatability of the observation.
- After any justified change, verify the same region and the surrounding operating conditions.
Keep the stock knock-detection and protection strategy understood and functional while investigating a correction. Document a changed function with its evidence and software scope; a reduced reported correction alone is not evidence that combustion improved.
Source context and adaptation
Adapted, paraphrased and reorganised from S4Wiki contributors’ Tuning, revision 5324, under Creative Commons Attribution 4.0 International. This wiki adds scope labels, cross-links and interpretation notes. The cited software observations have not been independently reproduced by this wiki.
Source sections: Timing, Knock recognition, Torque monitoring.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.