After I swapped the injector, the documented fuel bleed procedure is to press start without pressing the brake. That will operate the low pressure fuel pump for about a minute. I initially did that twice. After it wouldn't start, I must have primed the pump 6-8 times when using INPA.

Rheingold also has a fuel pump priming procedure which runs the LPFP for about 3 minutes. I did that twice. No change.

Pulled out my manual bleeder, removed the HP feed line to the #1 injector and made an air tight connection to the bleeder. I pulled 25 in of hg and nothing came out. I cranked the motor for 5 seconds. A tiny amount trickled out. Did this four times (pulling as much vacuum as possible each time) and I pulled about 200ml of fuel out of the rail.

Feeling quite confident at this point, I reassembled it all and hit the start button. No fire after three 5 second cranks.

I connected Rheingold to read the rail pressure while cranking. 5 second crank I see a couple bar of pressure. Off for a couple seconds and cranked again for 15 seconds which registered a max pressure of 45 bar. Off for a couple seconds, cranked again and by 10 seconds, I was up over 200bar and it started!!!! At the beginning of each of these cycles, the rail pressure came up faster and faster.

I took it out and the engine runs super smooth at idle, cruising and WOT. It now starts right away as it did before. No DTCs set.

I wish BMW's bleed procedure would have documented a similar procedure instead of LPFP operation for 3 minutes.