STD Maintenance General Idle too high in P/N, too low in D/R

Idle too high in P/N, too low in D/R

Idle too high in P/N, too low in D/R

 
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rolfi
My 300D is Onion-yellow!

79
11-06-2011, 05:49 PM #1
The car finally runs good, again.. Now with some other issues....

When cold, it just stalls if I don't press and hold the accelerator to keep the revs up... In all gears.
When hot, the idle in P and N is a little too high, but I can live with that...
In R, D, 3 and 2, the idle is too low. It starts shaking, and if I turn the steering wheel, it feels like it's going to stall.

Is there any way to adjust the "under load" idle, and cold idle, or do I just have to live with it?

-rolfi

1980 Mercedes-Benz 300D (US-spec)
+BMW E12, E21, E28, E30 and E32
rolfi
11-06-2011, 05:49 PM #1

The car finally runs good, again.. Now with some other issues....

When cold, it just stalls if I don't press and hold the accelerator to keep the revs up... In all gears.
When hot, the idle in P and N is a little too high, but I can live with that...
In R, D, 3 and 2, the idle is too low. It starts shaking, and if I turn the steering wheel, it feels like it's going to stall.

Is there any way to adjust the "under load" idle, and cold idle, or do I just have to live with it?


-rolfi

1980 Mercedes-Benz 300D (US-spec)
+BMW E12, E21, E28, E30 and E32

zacharias
Naturally-aspirated

16
01-03-2012, 05:13 PM #2
(11-06-2011, 05:49 PM)rolfi Is there any way to adjust the "under load" idle, and cold idle, or do I just have to live with it?

Short answer: sorry, not as far as I know. I had a 300sd with this problem, more prevalent in hot weather. I had to adjust the idle two or three times a year, according to ambient temperatures.

I was told that it's symptomatic of wear in the injection pump governor. If you are brave you can remove the pump and work on that, but as I am not that brave I just lived with it....

However, are you absolutely sure you have no air leaks in your fuel system? In my experience an air leak will magnify this problem a LOT. For example, if you have the old-style primer pump (the that has to be unscrewed to be unlocked), replace that and see if the behaviour improves.
zacharias
01-03-2012, 05:13 PM #2

(11-06-2011, 05:49 PM)rolfi Is there any way to adjust the "under load" idle, and cold idle, or do I just have to live with it?

Short answer: sorry, not as far as I know. I had a 300sd with this problem, more prevalent in hot weather. I had to adjust the idle two or three times a year, according to ambient temperatures.

I was told that it's symptomatic of wear in the injection pump governor. If you are brave you can remove the pump and work on that, but as I am not that brave I just lived with it....

However, are you absolutely sure you have no air leaks in your fuel system? In my experience an air leak will magnify this problem a LOT. For example, if you have the old-style primer pump (the that has to be unscrewed to be unlocked), replace that and see if the behaviour improves.

Captain America
Boostin' & Roostin'

2,221
01-03-2012, 09:06 PM #3
A question for OM616....


1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

Captain America
01-03-2012, 09:06 PM #3

A question for OM616....



1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

 
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