OK The car:
1985 500SEL
196,000 mI

On cold start - very very rough, black smoke worse than a sick diesel, rough in any RPM range

missing when hot at idle and black smoke, smooth at running speeds

Seems to be a vac leak somewhere, as climate control defaults to defrost when driving

could this be the only cause?

Not familiar with the gassers - about to resort to a indy

could the original timing chain have anything to do with it?
I have looked and looked for the vac leak w/tester but not familiar enough with the engine to find. It looks like the lines UNDER the intake are not in the correct spots. are there any diagrams for this?

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1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

I would check the cold start valve for leaking or spraying for more than a few seconds when starting. Try a search - several posts on how to do it.

You could also have a worn-out o-ring in the fuel distributor. If you can't check fuel pressure, get professional help.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

yes, I believe that is the final solution. I have plenty of porsche and mercedes DIESEL tools, but don't really want to buy another $3k in specialty tools for the benz gassers - not even my car!
Anybody know of a trustworthy mechanic in the Denver area? I have always done my own work and would hate to refer my dad to a bum.

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4