It could be that the turbo failed and is not spinning, hindering the amount of air the engine can get. You need to check and see if the turbo is frozen or is still spinning. With the engine off, remove the U-tube and see if you can turn the turbo by hand.
How did it run out of oil? Broken cooler line? Broken turbo oil line? How far/long was it driven with no oil?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13