diagnostics: confirm ICP bleed-off via --crank (peak 376 psi)

Direct on-truck measurement with the verified 1446 ICP PID: peak
cranking ICP 376 psi vs the ~500 psi firing threshold.  FICM Main min
48.0 V (healthy), battery min 10.3 V (adequate).  Diagnosis empirically
confirmed: high-pressure oil bleeds off during cranking.  376 psi is
"almost there" not zero, which fits a partial leak (IPR seat / oil rail
O-rings / partial STC crack) rather than a fully blown STC fitting.

- Capture the --crank output in crank-test-2026-06-30.txt
- Add EMPIRICAL CONFIRMATION section to diagnostics README
- Update handoff "resume at the truck" to lead with physical inspection
  (IPR -> STC -> oil rail O-rings), since the OBD-side diagnosis is done

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

diagnostics/2026-06-29-no-start/README.md

@@ -38,6 +38,24 @@ No engine P-codes, no FICM codes, no injector codes, no CMP/CKP codes.
   injector drive, cam/crank sync, and the FICM-to-injector path are all
   good when the engine is turning at running RPM.
 
+## ⭐ EMPIRICAL CONFIRMATION (2026-06-30 crank test)
+
+Direct measurement with `--crank` and the verified `1446` ICP PID:
+
+**Peak cranking ICP = 376 psi** — below the ~500 psi firing threshold.
+Full output in [crank-test-2026-06-30.txt](crank-test-2026-06-30.txt).
+
+This is the smoking gun. Truck cannot generate enough ICP during cranking
+to open injectors → cannot fire on its own fuel → needs ether every time.
+Matches the symptom-set perfectly.
+
+Side data from the same test:
+- **FICM Main min: 48.0 V** — healthy, corroborates the meter.
+- **Battery min: 10.3 V** — sag but adequate.
+- 376 psi is "almost there" not zero → suggests a **partial** leak
+  (IPR seat / oil rail O-rings / partial STC crack) rather than a
+  fully blown STC fitting (which would typically show sub-100 psi).
+
 ## ⭐ Key diagnostic finding: ether starts it every time
 
 Spraying starting fluid (ether) into the intake **gets the truck to fire,

diagnostics/2026-06-29-no-start/crank-test-2026-06-30.txt

@@ -0,0 +1,36 @@
+2026-06-30 -- dedicated ICP-cranking test with the new --crank monitor.
+Command:  python obd_reader.py --crank
+
+===== 6.0 CRANK MONITOR =====  00:40   1.8 Hz  frame 51
+crank the engine   q=quit  r=reset   firing threshold = 500 psi
+
+  ICP  [---------------------------------|------]    --   psi
+  PEAK    376 psi   BELOW 500 - keep cranking
+
+  FICM Main -- (min 48.0) [DOC]    Batt 11.8V (min 10.3)    RPM --
+
+  ICP trace (psi vs time, last 18 samples)
+   600 |
+       |
+   500 |--------------------------------------------------
+       |
+       |                                           #######
+       |                                        ##########
+       |                                        ##########
+       |                                        ##########
+       |                                        ##########
+       |                                       ###########
+       +--------------------------------------------------
+
+Verdict line at exit:
+  Peak ICP 376 psi -- did NOT reach 500 psi -- suspect high-pressure oil bleed-off.
+
+Headline:
+  * Peak ICP reached 376 psi during cranking -- below the ~500 psi
+    needed to physically open injectors.  Truck CANNOT fire from cold
+    start on its own.  Matches the ether-only-starts symptom exactly.
+  * FICM Main minimum 48.0 V -- healthy (corroborates the meter).
+  * Battery minimum 10.3 V -- sag but adequate.
+  * 376 psi is "almost there", not zero.  HPOP is making real pressure,
+    just losing it.  Suggests a partial leak -- IPR seat / oil rail
+    O-rings / partial STC fitting crack -- rather than a fully blown STC.

handoff.md

@@ -71,6 +71,13 @@ The 6.0 needs, to fire: **good batteries → FICM ~48V → ICP ~500 psi → fuel
   bus problem. Verified PID set now in `obd_reader.py`; reasoning + sources
   in [pid-research.md](diagnostics/2026-06-29-no-start/pid-research.md).
   Added `--dash` (real-time gauges) and `--crank` (no-start monitor).
+- **2026-06-30 ICP crank test:** ran `--crank` on the truck — **peak ICP
+  376 psi, below the 500 psi firing threshold**. Direct empirical
+  confirmation of the high-pressure oil bleed hypothesis. FICM min 48.0 V
+  (healthy), battery min 10.3 V (adequate). Output captured in
+  [crank-test-2026-06-30.txt](diagnostics/2026-06-29-no-start/crank-test-2026-06-30.txt).
+  Next: physical inspection (IPR valve first, then STC fitting, then
+  oil rail O-rings).
 - Pushed to `git.jpaul.io/justin/ford-obd`, branch `main`.
 
 ## To resume with Claude from the cab
@@ -80,22 +87,28 @@ no-crank, hot vs. cold, what changed before it died, and FICM/ICP readings if yo
 
 ## To resume at the truck (2026-06-30 state)
 
-The diagnosis stands: high-pressure oil (ICP) bleeds off during cranking;
+The diagnosis is now **empirically confirmed** — `--crank` measured peak
-HPOP outruns the leak once running. The toolchain can now confirm this
+ICP 376 psi (need ~500 psi to fire). High-pressure oil bleeds off during
-directly from the OBD port. Top actions, in order:
+cranking; HPOP outruns the leak once running. The 376 psi reading suggests
+a **partial** leak rather than a fully blown STC fitting. Physical
+inspection, cheap-and-easy first:
 
-1. **`python obd_reader.py --crank`** during a short crank. A healthy 6.0
+1. **Pull the IPR valve** (~15 min, ~$0). Bolted into the back of the
-   builds ~500+ psi ICP in 1–2 seconds. If ours stalls below 500 psi or
+   HPOP, top-rear of engine under the turbo. Inspect screen for debris,
-   builds very slowly, that confirms the bleed-off and is the smoking gun.
+   pintle/seat for wear, O-rings for cuts. A leaky IPR seat causes
-2. **Probe the FICM PIDs that were outside the scan window** to validate
+   exactly this "partial pressure" symptom.
-   the documented `09xx` family on this truck:
+2. **STC fitting visual** — between the heads under the turbo. Look for
-   - `python obd_reader.py --pid 09D0` (FICM Main, expect ~48V)
+   wet/oily film at the fitting joint. Ford TSB; classic 6.0 wear item.
-   - `--pid 09CF` (Logic, ~12V), `--pid 09CE` (Vehicle V), `--pid 09CD` (Sync)
+3. **Pull valve covers** and inspect high-pressure oil rail O-rings on
-3. **Visual under the valve covers + STC fitting** — the likely physical
+   each head. Bigger job but common 6.0 leak path.
-   source of the leak. STC fitting is the #1 6.0 culprit for this pattern.
+4. (Once a repair is attempted, re-run `--crank` — peak ICP should jump
-4. **Widen the brute scan** to round out the verified set —
+   to 500+ if the fix worked.)
-   `python obd_reader.py --scan 0900-09FF --scan-log scan-09xx.txt` and
+
-   `--scan 1600-16FF --scan-log scan-16xx.txt`.
+OBD-side follow-ups (lower priority now that we have the answer):
+- Probe the FICM 09xx family: `--pid 09D0` (Main, ~48V), `--pid 09CF`
+  (Logic, ~12V), `--pid 09CE` (Vehicle V), `--pid 09CD` (Sync).
+- Widen brute scan: `--scan 0900-09FF --scan-log scan-09xx.txt`
+  and `--scan 1600-16FF --scan-log scan-16xx.txt`.
 
 ## Open follow-ups
 Detailed action list lives in