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Discussion Starter #1

I have an E46 320d with the M47N[150] engine, it's on 180k miles (Engine and turbo were replaced by BMW at 100k because of swirl flap ingestion). The car has a tune from TheEnd too, I don't think this is related to the issue but just some extra info.

Every 1 in 50 starts it refuses to fire. I'll hold the key in the start position and it'll crank for 3 or 4 seconds before I give up. After waiting around 10 seconds then trying again it'll do the same cranking but not starting initially but eventually splutter into life. The revs will be unsteady and it'll cough a load of black smoke out the exhaust for around 30 seconds then it'll settle down.

I have a diagnostic laptop with the full BMW suite. I've scanned for codes several times using ISTA/D and nothing related comes up.
I have two fault codes relating to the charge air pressure signal (003F00 and 004191) and one that references my seat heaters being under voltage. I'm not sure if those charge pressure faults are genuine or not because the car drives and boosts well, I'm assuming they are down to the tune or EGR delete.

There's no pattern to this starting fault. Happens in warm and cold weather and during warm and cold starts. I did have a similar problem previously with it not starting correctly and a new MAF sorted it but now it's back.

To me this fault feels like fuel starvation during the start.

So far I've found the following possible causes by searching the forums:
fuel pump (there's two on this model?)
fuel control valve
crankshaft position sensor
camshaft position sensor

Things I've ruled out:
Fuel filter (new filter fitted during last service)
Fuel rail pressure sensor (Fitted a new one last year due to an error code logged for it)
Glow plugs (New plugs and new control unit fitted 2 years ago)
Bad fuel, this problem has spanned multiple tank so of fuel and it's always topped up using Costco premium diesel.

I don't mind just replacing parts but thought I'd try narrow it down a little first. Would anyone be able to add or eliminate any causes for my list of possibilities?
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