OM603 low boost following maintenance
 

Greetings, all. I recently rebuilt the turbo (full rebuild with new turbine/compressor wheel and 360° thrust, just for overkill) and injectors (new nozzles and pop testing) in my sister's '87 300SDL. I'm not a diesel expert by a long shot, but I'd like to think it went well. Having said this...

I can't get above 7psi boost, despite having great pressure before. The car came with the overboard protection disabled, and I've removed the ALDA for testing purposes. Despite the transmission shifting stupidly, the car pulls like a mule with the ALDA off (unlike before; I'll need to shim it before putting it back), but still no boost above 7psi in third with my foot buried.

Possibly pertinent: there's no significant over fueling with the ALDA removed. Definitely visible black smoke, but nothing close to an intentionally over fueled 6BT or anything I would describe as a cloud.

Other than that, I'm guessing I have a wastegate issue or other exhaust leak. I had a lot of problems getting the exhaust line to the turbo on (hammers were involved) and I had to get it hot to tighten it to spec. The wastegate seemed fine off the car, and I've tested it by clamping the line from the compressor housing to the wastegate, but it still could be an issue. Is there a good way to test this?

I've reached the edge of my knowledge, so any suggestions are truly appreciated. I can provide more info on request.