1992 300D OM602 feels like it is running rich
 

I have a 1992 300D that sat untouched in a garage for 10 years. 5 months ago I bought a new battery and it started after a few cranking cycles, but was running rough, as expected. It has 170,000 miles on it and the motor was rebuilt at 125,000 miles. It was my daily driver until I parked it in the garage.

In the past 3 months I have done the following:

New fuel, new fuel filters, Liqui Moly diesel purge, oil & filter change, new Tygon fuel return lines, new Bosch fuel injectors x5, new glow plugs x5.

All of this has resulted in a dramatic improvement in performance overall, but after warming up and coming to an idle @ 750 RPM for about a minute, the smooth idle begins to deteriorate to a shudder and occasional miss, some smoking, and a lot of diesel vapors. I can drive it down the road again with no problems, then stop and idle, and the pattern repeats itself.

To me it seems that it may be running too rich. My question is whether or not I can adjust anything to make it a little leaner, and how I would go about doing that.

Any suggestions or comments would be appreciated.

If it were mine I'd pull the injection pump and get it to an authorized Bosch shop for them to check out.

Thanks Jim.
 

I will start looking for a shop near me.

How long before this starts happening? Does it happen long after the time for afterglow?

It could be air getting into the fuel line somewhere. Does it smooth out after you have driven for a while?

I would try the simple thing first.

1) change ovp relay. Faulty ovp can cause erratic idle.

2) do a compression test. Could be stuck rings if it drives well at freeway speed.

3) ip, very unlikely.