uhryniuk
f830f8937d
New research/ROAD_TEST_LOG.md: the 2026-09-15 flash of 20262-arrow-delete-lowthrottle-composed.hex was a major real-world success (stalling fully resolved, decel backfire much reduced but not eliminated). Captures the live diagnostic reasoning that followed: correcting an overly-lean-leaning framing mid-session (residual decel pop is more likely a rich-unburned-mixture-with-no-SAI-assist problem, not a lean one), a structural hypothesis that the Idle Fuel Trim (CO) curve likely applies whenever the throttle is closed at any RPM rather than only at a literal stop (only 2 of its 32 points are currently corrected, and the untouched middle range lines up with the residual pop's RPM window), and the reasoning for rejecting airbox-baffle removal as a fix for decel popping specifically (wrong mechanism -- closed throttle isn't airbox-limited -- and risks worsening the separately-flagged, still unaddressed main-VE-table leanness gap). Also updates TABLES.md with the CO-trim applicability open question, and brings TUNING_GUIDE.md's "local research assets" section up to date (it still said maps were gitignored/unflashable, both stale). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FP2GaxS9HkUdL5sLBnjKje
166 lines
9.1 KiB
Markdown
166 lines
9.1 KiB
Markdown
# Keihin SH7054 (Triumph 865 twin, mechanical odo) — table map
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Reversed from `Nc()`/`Lb()` in `l.java` and validated against the stock reference
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maps. All offsets are in the reconstructed **flat ROM** (0x60000). Compute per map:
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```
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fe = c.a[Qd*48] # Qd from the s.a directory lookup on the map signature
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base = (fe[0] & 0x2F0) << 12 # = 0x50000 for the 865 twin family
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offset(table) = base + fe[<field>]
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```
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Main tables are **32 rows (RPM) × 20 cols (throttle), 16-bit big-endian**.
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## Axes
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| Axis | fe field | Entries | Values (20187) | Meaning |
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|---|---|---|---|---|
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| RPM (rows) | `fe[8]` | 32 | 0, 500, 900, 1000 … 10000 | engine speed, direct RPM |
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| Throttle (cols) | `fe[27]` | 20 | 0, 10, 20 … 780, 1000 | throttle %, ÷10 (0–100.0%) |
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## Tables (validated by production 20187 vs aftermarket 20188 diff)
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| Table | fe | Offset (20187) | Value range | Notes |
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|---|---|---|---|---|
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| Main fuel — cyl 1 | 11 | 0x56990 | 951–10480 | **strong**: 75% diff, smooth VE, aftermarket richer |
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| Main fuel — cyl 2 | 12 | 0x56E90 | 951–10680 | **strong**: 67% diff |
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| Low-throttle fuel — cyl 1 | 15 | 0x55590 | 0–10760 | 70% diff; starts at 0 (closed throttle) |
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| Low-throttle fuel — cyl 2 | 16 | 0x55A90 | 0–10810 | 68% diff; cyl-1 pair |
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| Fuel — base/idle | 9 | 0x55500 | 0–10760 | 61% diff; lower values |
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| Ignition advance — gear 1 | 19 | 0x587D0 | 13–600 | 4 evenly-spaced (0x500) 20×32 tables |
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| Ignition advance — gears 2–5 | 20 | 0x58CD0 | 13–600 | main operating map |
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| Ignition advance — gear 6 | 21 | 0x591D0 | 13–600 | overdrive |
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| Ignition advance — neutral | 22 | 0x596D0 | 60–600 | idle/free-rev |
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## AFR / target lambda
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`fe[2]` @ 0x52260 is an interleaved (value, breakpoint) curve where **128 = λ1.00
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(stoich, 14.7 AFR)** — e.g. `… 128, 500, 128, 400, 128, 300 …`. The `128` cells are
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the closed-loop lambda targets; disabling closed loop (O2 delete) lets you set
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these richer. Exact dimensions still being confirmed.
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## Scaling (confidence varies)
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- **Fuel** values are VE/fuel-mass in the ECU's internal units (≈ 0–10800). Real
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units (injector µs / VE %) need the ECU's fuel constant; relative changes are
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exact, absolute scaling TBD.
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- **Ignition** 13–600 is advance in an internal unit (candidate: value ÷ 10 = °BTDC,
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giving ~1.3–60°; the low-RPM row 90→14→20 fits a retard-then-advance curve). TBD.
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- **AFR** 128 = λ1.00 is solid (standard Keihin convention).
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## Fuel/ignition trim array — RPM-indexed, 32 entries, `0x53690`-`0x536AF`
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**Located and axis-mapped (Aug 2026).** A 32-byte array sitting just before
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the device-flags region (`0x53801`, `TABLES.md` above / `DEVICES.md`), one
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byte per **RPM breakpoint on the same 32-point RPM axis** as the main
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tables (`fe[8]`: 0, 500, 900, 1000, ..., 10000). Not addressed via a `fe[]`
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pointer for the maps checked (no `fe` field in `c.a[Qd*48]` equals `0x3690`
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for `20187`'s `Qd=32`) — likely a fixed offset relative to the device-flags
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struct rather than an independently relocatable table, unconfirmed.
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Evidence for the RPM-axis mapping: diffing `20188Map2009AIRBOXBONNY.hex`
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(the Bonneville SAI/O2 delete map) against stock `20188` shows **exactly 2
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of the 32 cells changed — at RPM=2400 and RPM=7000** — with all 30 other
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RPM-indexed cells byte-identical. That's `0x5369C` (index 12, RPM 2400) and
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`0x536AB` (index 27, RPM 7000) from earlier sessions, now understood as two
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specific points on this curve rather than free-floating bytes.
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Cross-checked against `20184dynoTuneSteveO2-Disable.hex` (America,
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open-pipe + airbox-snorkel-removed + O2-disable, real dyno tune) vs. stock
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`20186`: **nearly every one of the 32 cells changed**, by large,
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non-monotonic swings (e.g. RPM=1000: 231→63, RPM=4400: 235→5, RPM=5200:
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25→204). Not a smooth curve shift — looks like cell-by-cell dyno-session
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adjustment (consistent with a human tuner nudging individual RPM points
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after successive pulls) rather than a single global correction. Confirms
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this is a real, independently-tunable-per-cell array, not a scalar.
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**Identity: confirmed as "Idle Fuel Trim (CO)".** Crawled tuneecu.net's full
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docs site (`../tuneecu_site_mirror/`) and found the exact match in
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`TuneECU_En/tests.html`, TuneECU's live-diagnostics parameter list:
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> "Idle Fuel Trim (CO): lets you adjust the fuel richness at idle."
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> Available for "**Triumph without O²-Sensor only**."
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> (Counterpart: "Long Term Fuel Trim... Triumph models **with** O²-Sensor
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> only" — the closed-loop equivalent for bikes that still have the sensor.)
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This is a direct, official match to what we observed empirically: the table
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is specifically the O2-delete-relevant trim, exactly why it's what the real
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delete/dyno maps touch and the stock maps don't need to. `co_trim`/`ift_co`
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string resources (`strings.xml`: "CO Trim" / "Idle Fuel Trim (CO)") back
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this — "CO" = idle mixture richness, the classic idle-adjustment convention
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carried over from carbureted-era tuning terminology.
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**Encoding, upgraded confidence (Aug 2026):** found TuneECU's actual "CO
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Trim" edit dialog (`MainActivity.java`'s `La()`) and its value-scaling
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logic. Two independent code paths converge on the same answer:
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1. The dialog's clamp/display logic (`j8()`) treats the value as a plain
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signed range: `if (v < -128) v = -128; else if (v > 127) v = 127;`,
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displayed as `Integer.toString(v)` — no fractional scaling.
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2. A separate live-value dispatcher (`n.java`, a large switch handling
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various PID-style codes) has a case doing manual two's-complement
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conversion — `if (raw > 127) raw -= 256;` — immediately before storing
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into the same field (`MainActivity.Mc`) the CO Trim dialog reads.
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**Conclusion: the raw byte is signed two's-complement (-128 to 127), used
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directly with no multiply/divide scaling factor** — not the unsigned 0-255
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interpretation this project used everywhere earlier. **This retroactively
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resolves the "255 looks like a sentinel" puzzle** from the exhaust-family
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composability analysis (`COMMUNITY_TUNING.md`/`PERMUTATIONS.md`): unsigned
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`255` is simply signed `-1` — an entirely ordinary, near-neutral value, not
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a special case. Re-reading the earlier data with correct signs: the stock
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aftermarket-silencer family sits near `-1` (neutral), production/Arrow
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sits around `+69` to `+125` (already noticeably rich), and the real
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SAI/O2 delete map pushes to `+117` — a large, deliberate enrichment,
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exactly the physically-sensible story this parameter's name would predict.
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The composability conclusion (can't cleanly merge Arrow's delta with the
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delete map's delta) still holds — redone with correct signs, the combined
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correction still saturates past the `+127` clamp — but now for an
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intuitive reason (the needed correction is genuinely large) instead of an
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unexplained sentinel.
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**Not fully closed:** the *encoding* (signed int8, no scaling) is now
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well-supported by two independent sites; the exact real-world *unit* (is
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`+1` precisely "+1% CO", or a nearby-but-not-identical ECU-internal unit)
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isn't separately confirmed by either site. Raised from low to medium-high
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confidence — upgraded, not fully resolved.
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**Practical implication for composing tunes:** don't treat this array as
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"2 conflicting bytes" the way `compose_arrow_delete.py` originally did —
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it's a full 32-cell curve. A conservative mod (mufflers only) may touch 2
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cells; a more aggressive one (open pipes + airbox) touches nearly all 32.
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Composing two independent tunes' curves here needs the same per-cell
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arithmetic treatment as the main VE tables (`PERMUTATIONS.md`), not a
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handful of spot fixes.
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**Open question, raised from real-world testing (2026-09-15/16, see
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`../ROAD_TEST_LOG.md`): does "idle" in this table's name mean literal
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engine-stopped idle, or does it apply whenever the throttle is
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closed/near-closed regardless of RPM?** TuneECU's own docs say "at idle,"
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but the table has real, non-trivial entries all the way out to 10,000 RPM
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— hard to explain if it only ever applied near a stop. Circumstantial
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support for "applies whenever throttle is closed": a real-world decel
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sweep through the *uncorrected* middle of this curve (RPM 2600-6500,
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composed only touched points 2400 and 7000) produced residual popping in
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exactly that RPM range, while the low-throttle table fix (a genuinely
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different, confirmed-idle-adjacent table) independently and completely
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fixed literal stopped-idle stalling. That's consistent with this curve
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being live during the whole closed-throttle deceleration, not just at a
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stop — but it's inference from one road test, not confirmed in the
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decompile. Worth designing a deliberate test for if this gets revisited:
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does the CO Trim value visibly change on TuneECU's live-diagnostics screen
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while decelerating at 4000 RPM with the throttle shut, or only once RPM
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actually reaches idle?
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## SAI / O2 / lambda flags
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Now findable via the localised flat-ROM diff (20187 vs 20188), which isolates small
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single-byte changes (e.g. 0x50C13, 0x534AD, 0x59759) as prime toggle candidates.
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Confirming which is SAI vs O2 needs either bench testing or the finer `Nc` device
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logic — a follow-up.
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## Status
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Fuel and ignition table **locations** are validated end-to-end. Remaining: exact
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scaling constants, AFR dimensions, and confirming the individual device flags.
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