When I purchased this 1979 240D, it ran fine, but idled a bit rough. I tried Diesel purge, and it didnt seem to help the rough idle, but it ran ok. I thought I heard what some folks describe as nailing, so I fugured I had a bad injector. I found 4 rebuilt/checked injectors from a member on this site, and bought them. I just got around to installing them today. That did not solve my rough idle, missing out type of problem. I noticed also, after installing the injectors, when I tried to used the primer pump, it was leaking, so I put on a new primer pump. That didnt solve the rough idle, but did solve the leaking! :-). I cracked each injector line open at the injector, and each one made the motor run rougher. I had done a valve adjustment shortly after I bought the car, and they were off, plus I also checked the compression. I believe they ended up 290-310-310-300 or something close to that. This had a 1980 motor installed by the previous owner. Besides looking for more fuel/air leaks, what else could be causing my rough idle?
thanks,
Jim

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1979 Mercedes 240D (Sold to a neighbor last year,now I have room for a new one,looking for a 300D this time)
1980 Mercedes 240D(bought for a parts car, but I have fun driving it!)

Have a peek at the pre filter for air transiting as car is ideling. Will be a small stream of small bubbles and you can distinctly see them exit the filter if they are present in my experience. How good are your motor mounts? Your compression sounds fairly even. I always try to do the cheap things first. It might be worth it to check cam and pump timing as well as chain stretch if never done to your knowledge.
It's far better than a wrapped chain by neglect anyways. Did you have a look at your pre chambers when you changed the injectors out? What is your fuel milage like if known? Have you run car hard enough regularily to keep the carbon down?
If all the above checked out I would take my meter and analyse the glow plugs to determine individual cylinder temperatures. Dare I say milli volt method? Check the archives and ask questions if it gets this far.
If a large voltage discrepency was found on any two cylinders. I would transplant or interchange injectors and glow plugs to make sure the test was indeed balanced. Same results obtained with the parts exchanged then have the injection pump checked. Most problems on these cars are not the injection pumps. By the same token that does not mean they cannot wear over time.
This problem has been bothering you for awhile. Tackle it systematically checking the cheapest things first. You should locate the source in the process.
I will throw this out for general thought. You can always check out a set of injectors by systematically moving them one at a time to the same cylinder and reading the milli volt output of the glow plug on that cylinder. If all readings are very simular your injectors are okay. Has to be better than guessing or spending money with no indication it is needed.
This test is sensitive enough for our general needs in my opinion. It would suprise me if any bad injectors will slip past it. It is also a dynamic test where test stands only operate at a very slow unrealistic speed.

Barry,
When I did the first compression test and set the valves, I checked the timing chain. I did not do the drip method but rather lined up the marks up top on the camshaft(forgot what they were called), then looked at the indicator down below, it was at 2 degrees which I think is normal or acceptable. I have purchased new motor mounts as I think that will cure the shaking, but it will be a while before I install them. The "missing" out is what I am concerned with at this time. Most of the trips with this car have been 15 miles jonts to town, so I know the carbon buildup should not be the problem, plus I did a diesel purge on this after the valve setting. I didnt look at the prechambers, and on this particular 240 my speedometer works but my odometer doesnt, so I have not been able to check the fuel mileage(fixing the odometer is on my to do list :-)) You lost me when you said mili volt method!(lol)
Jim

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1979 Mercedes 240D (Sold to a neighbor last year,now I have room for a new one,looking for a 300D this time)
1980 Mercedes 240D(bought for a parts car, but I have fun driving it!)

Just check the archives for milli volt method. It may give you some insite. Basically it is just a way to measure the heat generated in each cylinder.

When I first got my '83 240D, it would shake so bad at idle your teeth would rattle. All I did was turn the idle speed up with the dash control and it smoothed right out.

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'83 240D 264k on 100% biodiesel/ 31mpg
83 300D 217K the $800 gem
'82 300D 267K the new WVO project car finished and driving for free
International tractor B275 on B100
Ford 555 backhoe on B100
Sargent 25 ton Rough Terrain crane on B50

This is definitely a "miss" or "hesitation" at times, just not he shaking.

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1979 Mercedes 240D (Sold to a neighbor last year,now I have room for a new one,looking for a 300D this time)
1980 Mercedes 240D(bought for a parts car, but I have fun driving it!)