Editing Openai/6940b2df-db80-8003-b707-4cc5cbedf6d9 (section)

=== Assistant: A very fast crank with no start usually means one of two things: ===
A very fast crank with no start usually means one of two things:
# The engine is not actually being turned by the starter (starter is “whirring”/free-spinning), or
# The engine is turning, but it has no combustion (no fuel / no spark / no RPM signal / no start authorization) — and “fast” is just how it sounds when it isn’t firing.

With your earlier detail (~11.4 V with ignition ON), low system voltage can also make BMW modules act drunk, but it usually causes slow crank more than “fast crank.” So we need to separate sound from facts with two quick checks.

==== Do this first — it changes everything. ====
* Have someone crank the car while you watch the serpentine belt / crank pulley up front. - If the belt/pulley does NOT move: the starter may be spinning but not engaging (or mechanical issue at the ring gear). That’s “fast crank sound” but the engine isn’t turning. - If it DOES move: the engine is turning. Go to Step 2.

(If you’re solo: prop your phone to record the belt area while you crank for 2 seconds.)

==== If you truly have 11.4 V key-on, clip your Autool E365 to the jump post + ground and keep it on supply/charge while testing. ====

Then check voltage with a multimeter:
* Battery posts (trunk), ignition ON: you want 12.0+
* Jump post (hood), ignition ON: should be basically the same as battery

If there’s a big difference between trunk posts and jump post, that points right back to distribution panel / cable / connections.

==== ### ====
* ISTA+ → Vehicle Test - If DME is missing / not responding → strong evidence of DME power feed / fuse link / distribution panel trouble (even if the starter still cranks). - If DME communicates → stop blaming power distribution as the primary no-start cause and move to live data.

===== - In INPA → DME → Live data, crank the engine and look for engine speed (RPM). - 0 RPM while cranking: crankshaft position signal issue (sensor/wiring) or DME not truly awake. - RPM present (150–300ish): crank sensor signal is likely OK → now it’s fuel/spark/start enable. =====

===== - INPA → CAS: check start authorization / key recognized. - If start isn’t authorized, it’ll crank in some failure modes but won’t inject/spark normally. =====

==== If the engine is turning and DME sees RPM: ====
* Fuel check: after cranking attempts, do you smell raw fuel at the tailpipe? Are the plugs wet?
* Spark check: if you have a spark tester, check one coil for spark while cranking.

No fuel + no spark together often points to start authorization/DME control, not a pump.

==== If what you’re hearing is a smooth, “zip-zip-zip” that’s noticeably faster than normal and almost too easy, that can mean low compression across multiple cylinders (rare, but real). ====

Fast triage:
* Watch the belt (Step 1). If it turns, do a compression test (or at least a quick compression gauge check on 2 cylinders) before you spend money elsewhere.

===== Reply with just this one result: =====

When you crank it, does the serpentine belt/crank pulley move? (Yes/No)

And if yes: tell me whether INPA/ISTA can talk to the DME and whether RPM shows while cranking. With those three answers, I can give you a clean, step-by-step “do this, then this” path to the exact cause — no parts cannon.