I have a vague recollection of your previous thread on this topic. Have you tried priming the bejesus out of it when it won't start? What was the result? Have you tried using an alternate fuel supply in a bottle under the hood when it won't start to rule out a fuel supply problem upstream of the engine compartment? Have you tested the glow plugs when it won't start to confirm they are getting 12 volts and have proper resistance?

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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