Parameter entry points
MS4X describes MS41 fueling through injection-time maps and corrections. Use these names to locate the corresponding definitions:
| Area | Parameter examples |
|---|---|
| Cranking | ip_tipr_cst__tco; ip_ti_cst__n__tco |
| Base / VANOS | ip_tib__n__maf; ip_ti_ivvt__n__maf |
| Full-load factor | ip_ti_fl__n |
| Injector data | c_ti_min_iv; ip_ti_add_dly__vb |
| Ignition | ip_igab_is__n__maf; ip_igab__n__maf |
| Idle | ip_n_sp_is and load-state variants; matching base-PWM maps. |
MS4X reference; MS4X reference.
Injector changes: preserve the quantity
Make an inventory of the maps affected by the proposed injector change. Label every entry by unit and purpose before applying a multiplier. The flow-ratio example in shared injector guidance concerns fuel-delivering time; it does not supply latency or a correction for dimensionless tables.
Separate the calibration into testable questions: does the engine start at comparable temperature and voltage, is hot idle stable, are both banks consistent, and does measured lambda track the intended result in the evaluated region? Keep the evidence beside the edited table rather than treating one global correction as the result.
Explain a full-load result
A table display labelled “lambda” may be a definition’s interpretation of an internal factor. Inspect the conversion and baseline assumptions before treating the displayed value as a measurement. Compare with suitable measured lambda and note the active corrections and learned state.
Idle and ignition review
Build an idle test matrix: cold/hot, A/C off/on and, where fitted, automatic transmission neutral/drive. Record target speed, actual speed and available actuator command. If a target is reached only with an actuator near its limit, investigate the baseline and hardware before extending the target further.
For ignition comparisons, keep temperature, fuel, load and active operating state consistent. Use a documented load axis and preserve diagnostic evidence for any apparent intervention. The map names above are discovery aids, not universal addresses or recommended timing values.
Sources and scope
Original reference notes by Tuning Wiki, informed by the linked MS4X Wiki pages. MS4X Wiki contributors and the authors credited by each linked project remain the source authors. Sources checked 10 November 2026. Suggested validation steps and worked arithmetic are editorial guidance; they are not a tested calibration or a claim of hardware verification.
- Siemens MS41 (revision 23746).