I have had two 300D s and both of them idle rough. The first one got smashed up before I could try to figure it out. I was wondering if this is the nature of the beast as a friend of mine has an 84 300td and an 85 300td and they both idle rough too. Once you step on the pedal on any of these cars they smooth right out. You can actually feel the car "surging" when you are at a stoplight in gear with the brakes on. Any thoughts?

a diesel purge, if you haven't done that yet. Diesel Giant sells a complete kit to do it on his website, http://dieselgiant.com/diesel_parts_for_sale.htm

But that's just basic maintenance that's supposed to help with knocking and nailing and increasing hp. Any mechanical fix is beyond me...

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1983 MB 300SD Turbo Diesel

Diesel Purge
Valve Adjustment
Engine Mounts or Motor Mounts
Rack Dampner Screw
Italian Tune-up

No it is not the nature of this engine to idle roughly.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I've wondered the same about the idling. My 1980 idles rough too, even after a complete engine rebuild including new nozzle tips, everything except a pump rebuild. Don't have the surging though. I just assumed that is the nature of the 5-cylinders. It too smooths out nice when it is opened up a little.

You might want to check out the throttle linkage adjustment as far as the surging. On my '80 it has the vacuum bleed-off valve on top of the valve cover. This is suppose to keep the transmission in 2nd gear at idle. Might be adjusted wrong and shifting into 1st.

Just saw your post. Non-turbos do not have the rack dampner screw, do they?