2200 sounds like the default pressure in the pcm.
Ipr unplugged will always cause a no start. Look at it as a on/off switch for the hpop. Defaults open/off.
What is the tach showing while cranking? Take a look at all the sensor readings.
If you didn't have the system dry, I doubt it would be air in the system. But it could be possible.
Even though the pcm is telling you 2200, I would check the hpop drive gear bolt. I had one torqued down once, engine would turn by the bolt, so would think it was tight and all was well. Wouldn't put out any pressure. Turned out the gear wasn't seated to the shaft.
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