Check the wires -- Volvo wiring is notorious for brittle insulation when it ages, and its entirely possible that the insulation broke off the injector wires under the covers, causing shorts. No juice to the injector, no start.
Also, did you replace the seals? Volvo injector seals are bad about leaking, so if you R&Rd the injectors and didn't put new seals in, you have a nasy vac leak. Replace seals should fix.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!