Could someone explain what the 'increased idle speed' system is on the newer 617's without the manual idle control knob. Mine may not be functioning wellon my 85td.
On my 77 300d if I try to start immediately after the glow plug light goes off it takes a few revolutions of the crank before it fires up. If I wait 40 seconds it starts on the first compression stroke. So, the glow plugs can't be cooling down in that period.

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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