i have 1983 300TD with about 250K miles. problem started last summer. car wouldn't idle after startup. got worse as we moved to Taos, NM at 7500 feet. car has lots of kackle even warmed up and smokes white smoke until completely warm. this car has always had regular service. 3K mile oil changes, valves were set last summer, new timing chain about 10K miles ago. any ideas?? is my fuel pump wearing out?? also, is there a way to lean out for altitude? i've already backed off the Alda until power dropped off.

Injection timing off is my bet. Normally advanced is too much cackle/nailing and white smoke is retarded so see which way works when you tilt the pump

Smoke is the only thing to worry about at high altitude and sounds like you've done that adjustment.

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

Two fifty thousand. Injectors ever been pulled and checked? Compression checked? Believing what the odometers indicate on the 123s is an act of faith at best. Unless you really know the individual cars past. Rough starts? Glow plugs ever been checked?

Mine sounded and ran horribly, even through new glow plugs, injectors, filters, resealed tank, valve adjustment, and probably some other stuff too. The big turning point for the car was changing the diaphragm in the rear of the injector pump. Mine had become porous and started leaking. Check the white plastic vacuum line off the back of the pump, make sure it is still white. Mine was much darker, indicating a compromised diaphragm.

Smoking at start up is typically associated with worn valve stem seals..
and it may have to do with the oil which they allowed to seep down to where it could burn instead of ' till the engine is warmed up '... so that can give a false image of the cause...
They are a straight forward repair... the parts are cheap ... typically takes about three hours to accomplish.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html