1984 OM617 with suddenly erratic idle
 

Aloha all

I am baffled and hoping I can get some guidance.

I have an 84 300 td wagon and when I went to drive it today the engine wouldn't idle but stayed reved up to maybe 2000/2500 rpms ? (tach is broken) when I tried to shift it into gear to get it home, it would just stall. At home I tried to adjust the idle with the idle adjustment screw and can't seem to make sense of how it responds. when I turn it in- nothing and then sometimes it will idle down and stall and sometimes will continue to just run at a high rev.

I just replaced the injector nozzles and reset the valves. It is not a great engine and compression was kind of low with one cylinder down to 220 ( rest between 300 - 350 ) and some blowby When my wife drove it yesterday she said it ran 'fine' and then all of this started today?

What am I missing or doing wrong?

I am also still looking for someone experienced to barter a 617 tune up tutorial for some time in our B&B on Molokai in Hawaii. There is no Mercedes shop or mechanic here. I am self taught. I am an experiential learner and it is a frustratingly slow learning curve...

Check the throttle linkages as per chapter 30 in the FSM

Make sure that the floor mats in the cabin aren't restricting the movement of the accelerator pedal and make sure there's a spring still attached to the accelerator linkage at the bulkhead and at the injector pump

It sounds like it might be starving for fuel. I'd start by changing your fuel filters and treating the fuel tank to a good dose of biocide to kill any bacteria that might be clogging the filters.