Is there an automatic cold start high idle in my 83 300D Turbo? If so, mine is not working. What to check?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

No, there isn't so there is nothing to check for! Put your foot on the accelerator and don't go above 1000 RPM. Hold it at 800 until it can do this itself and you should be fine.

i just use a Twig as a accelerator holder, just place it in between the stop and the black box it always works....

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

isnt that a rather strange phenomenon? The car starts out stumbling ,with poor combustion.. but if you add more fuel to the fire.. it smooths out?

__________________

No, because the extra fuel isn't necessarily burning any better, but more of it burns, which gives it some higher rpms, which means more heat, and more combustion cycles per second.....so it keeps getting warmer and warmer....a la better combustion in a few moments of doing that.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

My 240D has a manual dle speed control knob. Why did Mercedes remove the cold high speed idle feature in the 300D? Mine stalls out in 10 F cold starts unless I feather the throttle for 30 seconds or so. Does yours do the same?

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Don't all 123's have idle knobs? The last thing I do after shutting the car down at night in winter is set the idle knob3/4 turn to the left, so first thing in the morning all I have to do is glow the snot out of it( 3-5 minutes) and I get almost instant starts no matter how cold.

__________________
1981 240d
Newport,RI

The 300D Turbo doesn't have a high idle knob. There is no High Idle knob for the 617.95X Turbo that I have seen! I do set my Idle at 900 RPM in the winter when fully warm and it seems to help.

Mine did that too, until I put Rotella "Synthetic" 5w-40 in it. It had to do with the governor in the IP, and the cold engine oil's viscosity not letting the governor respond as quick as a warmed up engine.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

My idle is set to 550 rpm.....and it start/holds it fine even at 0F. I have the afterglow system, and that helps, but it still starts awesome. Its running 5w40 Rotella....that helps a lot!

Anyone ever looked at dino 15w40 at 0F, its almost a solid!

5w40 still actually flows (slowly) at those temps....huge improvement.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)