Do a search on ALDA. There'll be a ton of hits but most will cover some aspect of checking and cleaning the signal line that tells the injection pump to accommodate the extra air provided by the turbo.

My SD is surprisingly perky off the line. The rear really squats when you get on it. After that I wallow in my own smoke until the turbo kicks in

Sixto
91 300SE
87 300SDL
83 300SD