W124 300 Diesel engine Idle adjustment 1992

[Frijz]

I've been scrolling through the threads and articles on trying to increase the idle on my 1992 300TD. It only needs to be adjusted a tiny amount but I haven't really got my head around how to do it. Any help appreciated

 

[bolide]

They normally idle at about 700 rpm. Is there a reason you want it to idle at a different rpm?

I imagine there's a stop on the fuel rack on the back of the injection pump, but that's a guess

Nick Froome

 

[Druk]

There's a little screw with lock-nut on the rear body of the pump. iirc it screws outwards to increase idle...but you'll soon find out for certain.

This one, center of pic to the left of the orange thingy.

 

[Frijz]

It currently idles around the 500 mark so if it's meant to be 700 its off more than I thought. When its cold it runs rather lumpy however it is fine if I very lightly press the accelerator to up the rpm. Is there any sort of idle controller that may have failed? Will have a go at adjusting the screw

 

[Druk]

Is there any sort of idle controller that may have failed? Will have a go at adjusting the screw

Yes. The pink/orange thing ^ is idle-up when engine cold. Check the connector is still attached and that the wiring is not corroded inside the plug (which springs apart).

Having said that...my engine has no cold advance fitted and I simply adjusted the idle slightly higher to compensate although mine is a manual. If it's too high and you have an auto box it will slam into gear and creep badly when stationary. It's a happy medium you need.



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[Charles Morgan]

Just started up the one sitting on my drive and it is exactly as Bolide says - about 700rpm and no issue with slamming into gear etc.