If you confirm functioning glow plugs by putting 12 volts to each one, I'm guessing that this case could be similar to quite a number on here where a long sitting engine has refused to start. Typically, they have been started by pull starting. Once pull started, the engine returned to normal. I'd give that a try.

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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