Cheapest and simplest thing you're missing is air in the system. By pulling the injector pipes you've made it tougher on yerself to start the car for obvious reasons - filling the pipes with air.

What's history of the vehicle? How long off the road? And are you using the pull-knob engine glow system correctly? No shame there, its complicated ritual starting primitive diesels with old fashioned glow system. Arguably takes 5 minutes to start the car, even if you know what yer doing.

Your 220/200D w110 Fintail is diamond in the rough. Learned just last week at Vintage Forum that engines from 115's will bolt straight in. Hell, the only reason i wouldnt drive finbody diesel everyday is because its too sloooow in its original 190/200 configuration even for me.

The 220D engine upgrade is entirely kosher and oughta be considered a blessing. And shelling out for rebuilt injector pump is worthwhile assuming sheetmetal's rust-free.

__________________
'80 300SD/ w116
'79 240D 4-spd
'71 750cc Guzzi

previously owned:

'83 240D 4-spd
'77 280SEL 4-spd
'74 280/8
'72 250/8
'65 220Sb 4-spd
'63 220Sb 4-spd
'63 190c 4-spd
'61 220Sb 4-spd
'60 190b 4-spd