i was wondering how to adjust my idle speed on my 85 300td. for some reason when it reaches operating temp it seems to stay at around 1000rpm and even sometimes 1100rpm and its getting on my nerves because it is kinda loud just idling at that high of an engine speed.. is there a way to adjust the idle speed without using a data link connector and a scanner?

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1985 mercedes benz 300D turbo diesel
1998 VW GTI VR6
1996 VW GTI 2.0
1999 saab 9-3 turbo
1987 300sdl (sold)

Ok, I will admit to chuckling at that question. Now, from page 2-21 of the Chilton Manual:

1. Run engine to normal operating temperature.
2. (not applicable to your model)
3. Disconnect the pushrod at the angle lever.
4. Check the idle speed. Adjust by loosening the locknut and adjusting the idle speed screw. Tighten the locknut.
5. (not applicable to your model)
6. On all models ecept the 1981 turbodiesel, depress the stop lever as far as possible. The cruise control Bowden cable should be free of tension against the angle lever. Use the adjusting screw to alter the tension. Let go of the stop lever. The Bowden cable should have a slight amount of play.
7. On turbodiesels, adjust the pushrod so that the roller in the guide lever rests free of tension against the stop.
8. Put the automatic transmission in Drive and turn the steering wheel to full lock. The engine should run smoothly. If not, adjust the idle speed. Disconnect the cruise control connecting rod, and push the lever clockwise to the idel stop. Attach the conecting rod, making sure the lever is about 0.04 inch from the idle speed stop.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

Its also a risk to the engine. A little past 1000rpm and the engine speed is not governed, the engine will revv to 5000rpm on its own and stay there if there is no load (in P or N).

Check your linkage for binding.

ya i thought that the datalink thing was kinda odd to hear, i printed somthing out on ALLDATA (nodata) at school and it said idle speed should only be adjusted with plugging in a scanner into it, and i saw the little circular connector under the hood by the drivers side fender (9 pin?) but thats y i ask on here.... so whats this angle rod or whatever that you are talking about? there are so many rods that move under the hood when the throttle is pressed down that i cant even tell what one to adjust.

also, at WOT where are the shift points suposed to be? as in rpm, my car shifts out of each gear at about 4600rpm at full throttle, is that where it should be?

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1985 mercedes benz 300D turbo diesel
1998 VW GTI VR6
1996 VW GTI 2.0
1999 saab 9-3 turbo
1987 300sdl (sold)

Yep.

where is the angle lever? can anyone post a pic of what i need to adjust to lower the idle speed?

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1985 mercedes benz 300D turbo diesel
1998 VW GTI VR6
1996 VW GTI 2.0
1999 saab 9-3 turbo
1987 300sdl (sold)

Hope you can see it. You'll need a DEEP 14mm socket and a flat screw driver. The idle should be around 750-800 rpm.

Attached Thumbnails

 

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83 SD

84 CD

I have my SD idle at 900-1000 rpm hot, otherwise it is too low when it is cold.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

awesome thanks alot man. really appreciate it, ill be tryin it out tomaro. thanks again!

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1985 mercedes benz 300D turbo diesel
1998 VW GTI VR6
1996 VW GTI 2.0
1999 saab 9-3 turbo
1987 300sdl (sold)

dont they have a cold idle solenoid? Thats ridiculous to have the idle so high just for when its cold..

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-->1971 mercedes 220D; 617 951 engine, 4 speed

Not on mine, the after glow plugs take care of cold weather issues.
That being said, the '85's have many different items.

TurboSDL, No prob, folks are here to help.

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83 SD

84 CD

Vancouver is pretty mild isn't it? 750 rpm should be fine in the winter.

Heck, 750 rpm should be fine in Edmonton as well.

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Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)