This is more informational than a question.
1995 S350D 603 engine with about 270,000 miles. Turbo works fine until engine warms up. Even with the engine warm the turbo works for about 1-2 minutes after starting the car.

Cause:
ERG valve not functioning due to split vacuum control hose to the ERG.

Why does this cause a problem:
In the W140 and beyond (Don't know about the W126 diesels) if computer senses the ERG systems is not working it turns off the turbo charger. The ERG is not supposed to function for the first 1-2 minutes after start up, so it is not looking for it then. It is also not supposed to function until after the engine has warmed up, so it is also not looking for it until then.

Replaced the hose with some 7/32 vacuum line and I'm back in business. I think 3/16 would fit a little better.

There is a 606 thread out there where someone built a resonant circuit to trick the computer into thinking that the ERG was causing a pressure drop in the intake manifold. I need to go research it and see what I can do to backwards engineer it down into a W140 with a 603. I would like to see the EGR go away.

Anyone know where the ARV is on a 603? is there one? I bet there is and I just have not found it yet.

Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.