How do I adjust idle speed - '78 300D
 

My car idles a little slow - especially with A/C on and will occasionally stall (most likely when I have been driving for a while and I pull to a stop - for instance, after exiting the interstate and coming to a stop).

How do I increase it? Is the only way to adjust the idle cable - which I have installed but have not really adjusted. This is a non-turbo '78 300D. Thanks.

Ryan

The non turbo models have an idle adjust knob on the left of steering wheel on lower dash. I'm assuming you replaced the cable that this knob uses to adjust the linkage to IP to increase rpm. you simply turn up the idle when necessary, like for starting in the mornings, and adjust to preference as necessary.
I don't remember if the IP has the same adjusting screw as the turbo's do in addition to the idle adj knob/cable.
I really liked the idle adj knob on my '80 wagon. Very handy.....

Does the idle adjuster do anything on my 300TD-T?
 

My '81 300TD (turbo) has the idle adjusting knob, but the manual says this is for non-turbo models. Does it do anything? How do the turbo 917 engines deal with the idle speed that that the non-turbos don't?

Thanks.

Mike

I like the idle adjustment knob on my '80 300TD. I read somewhere that it's a good idea to press down the accelerator pedal a little when using the knob to increase idle speed. This tends to ease the strain and wear on the knob-cable mechanism. Steve

617 not 917 (thats another Greman car)
You should have the little knob left of sterring column. Yup, using your foot removes pressure from the cable when adjusting. I like to keep mine adjusted so when retarded the idel is ok at normal running temp. If this does not work, you have other problems. This adjustment should be in your car manual.
Good luck.

Do you think I can fit a 917 engine in my W123? :D

I'm not sure how/why the 617 turbo maintains cold temperature idle speed without the manual adjustment, there must be a difference in the IP design. It does work, my turbo will idle at close to normal rpm after a few seconds, even in very cold temperatures.