This is what mine does! Except mine seems to be more heat-related... it's worse on hot days and definitely worse with high engine temps or a/c on.

I thought spec on the ELR knob was 4 for our cars? Could be wrong...

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

I read on the FSM that there's also a lock nut and adjustment bolt near the magnetic/electronic idle plug on the pump. That also adjusts the idle.

There are things in that pump that regulate/maintain idle speed. I'd assume these parts wear and need adjustment at times. Just wish someone would pipe up with some knowledge here. I read there are electronic and vacuum controls that are idle related on the pump.

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

I adjusted the mechanical idle control a bit and didn't notice any difference. Maybe I need to make more turns on the bolt. I probably did one full turn.

Should it be able to continue running with the plug pulled from the Injection pump under a load? i.e. the A/C running. I see the specs in the FSM are that it should be around 560??? RPM's unplugged. And I think 640 plugged in.

Attached Thumbnails

 

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.

Nick and others,

it should be just idle adjustment:
unplug the ELR on the backside of the IP and adjust rod stop (mechanical idle adjustment) to just below 600 rpm.
Mine did the same. My theory is that s.o. tried to lower the idle mechanically with the rod stop screw without touching the ELR. Now the ELR trys to regulate idle but mechanically the pump is too far low and it takes time to get the revs up if ever.

Tom

On my '87, I noticed that, at idle, the red fuel shut-off lever seems to sink down under its own weight and the idle goes down a little. I can pull the lever back up and the idle speed increases a few RPMs. I don't know if it is supposed to do that and haven't run any additional tests. If that problem gets worse, I can see that the engine might almost stall for lack of fuel. Vacuum problem or something in the shutoff sub-system?

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

My 190 does the same thing. I has never killed the car. I have read that there is an idle adjustment knob but cannot find it anywhere. Can anyone explain where it is or give me a pic?