Hello, I recently bought a 1973 Mercedes 220D. I LOVE the car, the simplicity and logic of the design. It the engine itself seems good, and I think compression is probably ok. It has more power than I expected actually (I used to have a 240D, and this one has at least as much power).

Well, the problem is that when it is cold, the idle is irregular - revving up and down (in about 1 sec intervals). There are some comments here from people who mention a "damper screw" on the back of the injection pump that may need adjusting to smooth out the idle. However, they were talking about other Diesel Mercedes Models, and I wonder if anyone knows about the 220D specifically.

I have already replaced the fuel filter, and poured injector cleaner in the tank. This made no difference.

So might the injection pump need adjusting? Related question for any experts out there: Will an injection pump from a 240D (W123 series) fit into a 220D (W115 series)? I am asking because I am able to get hold of one, and I wonder if it would fit physically, and work...

Thanks to all of you in advance!!!

 

Thanks a lot for your time and expertise.... I really appreciate the diagram. I will attempt to study it.....
Have a nice day, and all the best!