Once and for all how to adjust idle for 601?!
 

I have never been able to find anywhere how exactly do you adjust the idle speed on my OM601!! I would prefer mine to idle a gnat's ass faster. Anyone, please? Thanks in advance.

It is my understanding that this is done by adjusting the screw behind the pump. You should have a diaphragm with an air line attached to the back of the injection pump. The diaphragm is attached to a threaded member into the back of the pump. THe idle is adjusted by adjusting the position of the threaded member into the back of the injection pump.

One caveat I have made this adjustment over 200kmi ago, and I have not -- to date-- caused any catastrophic failure. The mileage just keeps on ticking.

Loosen the nut locking the vacuum diaphragm assembly at the top rear of the pump and turn the vacuum unit in (to go slow if I recall correctly) or out (faster) to adjust the speed - which should be about 750 rpm (+/- 50) with th engine warm. Vacuum (controlled by a 17 deg. C vacuum switch or the swicthover valve activated when the AC compressor is engaged) to the vacuum device should raise the idle about 100 rpm).

Marshall

Great, thanks! I will check it out tomorrow when I get a chance.

Hallo
 

der Dieseling Doktor !!!!!

Willkommen !!!!!

Nice to see you posting on this forum.

Well I loosened the nut and turned the screw counter clockwise (out) to increase the speed. It doesn't really seem to make any difference which way I turn the screw. Though I hope this may solve my problem of where the car seems to miss or be off rhythm. The engine only does this after a highway run or a very long drive, so when the engine is good and hot. Then at idle the engine will feel like it is skipping. I wish I had an audio recorder to capture the sound it makes. Tapping the accelerator stops it, but then it may go back to the skipping again.

I am way late to this thread but my 190D 2.2 is having the exact same problem. Rough idle after very long drive only. New filters, injectors, glow plugs to no effect.

Thanks!

I believe some people had rough idle issues from the below part:
Long Fuel Pressure Relief Valve/Overflow Valve Thread
http://www.peachparts.com/shopforum/showthread.php?t=234609
Another from hunter
Fuel injection pump starvation with a good lift pump
http://www.peachparts.com/shopforum/diesel-discussion/247039-fuel-injection-pump-starvation-good-lift-pump.html

I owned w124 602.912. my mechanism is probably same as 190d. However I still unable to understand the locking nut for moving the pneumatic diaphragm

Here is a picture of my pneumatic idle, which nut needs to be loosened?

OM601 uses a factory set idle speed with a vacuum trigger ~100rpm increase when the A/C is on. On my car I just directly connected the line from that to the vacuum system so it always ran 100rpm higher.

The older 61x engines were set with a screw on the idle stop, but the 60x engines are different.

Mine is 602.912. yes a vacuum to the back pneumatic would increase idle.

I plan to hook up a switchover valve triggered by ac compressor to get vacuum increase idle. But I would need to reduce the set idle by turning that vacuum unit in. I am afraid I might damage something on the process.

602 is electronic idle speed controlled no adjustments. Normal temp 600 to 650 rpm low temp or Ac on 750-800 rpm.

In US version it probably has EDS.

Mine is Euro. As seen on my picture it has Pneumatic Idle. I was asking in this thread since 190D has similar mechanism. Probably some 190D owner could confirm which nut to be loosen.

I dunno if just raising the idle speed is your solution to the problem your having... Kinda seems like it's just gonna hide what ever issue the engine is really having

You can still manually/mechanically adjust the idle on eds 601/2/3/6 mechanical pump.
Back of the pump, up top, just above the big red round thing with two prong plug up top.