High Idle word of advice OM617

[Waste_Gate]

This morning before work, the temp was down to 28 degrees so I let the benz warm up like usual but this time I decided to set a high idle for a few minutes. I took a flat head screwdriver and put the handle part on the pedal and found a lip on the kick panel where the other end could push against.

My idle is usually 700 rpm when its that cold but gets up to about 850 after driving for a while. I adjusted the orientation of the screwdriver until the tach read about 900. I went back inside to gather some things and after about 4 to 5 minutes I noticed the idle was a little higher but didnt think much of it.

Within about a minute of noticing it, the idle was climbing quickly and by the time I got outside and unlocked the car, the idle had jumped to about 1300. I mean it really started taking off.

I read some posts from forcedinduction and others saying the governor can't keep the idle down past 1000 RPM and now i have first hand proof.

If you plan on setting your idle high by pressing on the pedal with something, make sure you account for the difference in engine speed once the oil warms slightly among other things. Good thing I didn't decide to take a **** like usual .

[pawoSD]

With the pedal slightly pressed it probably wouldn't have gone much over 2000rpm. I can hold mine anywhere from 1600-3000rpm with various pedal positions without it running away....

[Waste_Gate]

Originally Posted by pawoSD

With the pedal slightly pressed it probably wouldn't have gone much over 2000rpm. I can hold mine anywhere from 1600-3000rpm with various pedal positions without it running away....

PawoSD, All i could think of in that short amount of time was "run-away" which is why i took such quick action. Usually I cant hear the engine running with the storm door shut but when I heard it over the TV, I knew something was a lil different. Thanks for the insight, it kind of reminds me how holding the pedal at a constant position within the boost range allows the engine to eventually take off. Its not something I expected but now i know what to look out for.

[PackerEdgerton]

Even when it gets that cold around here, I simply drive slowly and gingerly for a few minutes, letting it get a bit warm before I drive it normally. I have never found that the idle speed control cable was insufficient for the job. Not sure why one would need to have to have some accelerator hold-down. You could always make sure your idle speed cable slack has been adjusted out.

Sincerely,

Packman

[Diesel911]

Originally Posted by PackerEdgerton

Even when it gets that cold around here, I simply drive slowly and gingerly for a few minutes, letting it get a bit warm before I drive it normally. I have never found that the idle speed control cable was insufficient for the job. Not sure why one would need to have to have some accelerator hold-down. You could always make sure your idle speed cable slack has been adjusted out.

Sincerely,

Packman

I will make a guess that he wanted the inside of the Car Heated before he got into the Car or the the Car warmed up enough that there would be heat inside when he started driving.

It is a good case for using the Block Heater if he has one.

[Waste_Gate]

Originally Posted by PackerEdgerton

Even when it gets that cold around here, I simply drive slowly and gingerly for a few minutes, letting it get a bit warm before I drive it normally. I have never found that the idle speed control cable was insufficient for the job. Not sure why one would need to have to have some accelerator hold-down. You could always make sure your idle speed cable slack has been adjusted out.

Sincerely,

Packman

Turns out its a 617.952 so there's no idle speed cable, I'd like to retrofit one by the hood release though.

Diesel911, Actually my problem is a partially stuck open thermostat. Since I can't get around to replacing the thermostat right now, i figured the engine could use the heat more than me. By the time i drive 15 minutes through the city to get to work, the temp is only at about 75 and only about 70 if I don't warm it up. I know it doesn't generate much heat idling but i think it helps. During the summer I would always reach operating temp before getting to work.

[cooljjay]

the earlier w123's have an idle control knob on the dash for this reason....mine has broke but like another poster stated out...

I simply start it....idle for a few seconds to oil pressure builds up and take off....never an issue and today it was 22 when I went out...

[aieeegrunt]

My driveway ends at a highway. I figure letting the car idle for ten minutes with the idle control knob all the way up is far better than flooring it stone cold.

[t walgamuth]

it seems wrong but you really don't have to let ad diesel warm up.... just don't floor it immedietly.