My 93 E-300, 2.5 Turbodiesel will fire immediately at start up and idle smoothly wether it has set for one day or one year. BUT after about one minute it will start to miss, shake, rattle, roll, and a blue/black smoke will appear unles you give it the throttle and rev it up to about 1500 or 2000 RPM..
Once past about 60 Deg. C it runs like a new car and idles as smooth as a 5 cylinder engine can. This condition only happens after the car has set and completely cooled down, like over night.
Had the glow plugs checked out, ok, new fuel filter, also had the injectors re-built. The car uses no oil, and the coolant level remains stable. This smoke smells like a rich fuel mixture, if it were a petrol engine I would think the choke was stuck.
What can this problem be?

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Den
1993 MB 300D 2.5
2001 VW Jetta TDI 5 spd.
2001 new bug TDI 5 spd.
Motorcycles

A couple of thoughts. Is the thermostat stuck open and keeping the engine to cool at start up? A long shot but your symptoms are interesting. If it was a compression issue I would expect poor starting, still I would do a compression check on each cylinder. I would have done that when I was changing the injectors out. And as always check the timing. Not sure why it would fail that way but sounds like it could be a timing issue. Maybe one of the master mechanics here can figure it out. Have fun.

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My Daily : 96 E-300 Diesel with 195,000 miles
Retired: 92 300D 2.5 T 345K miles and for sale
Retired: 95 E320 157K miles and currently parked with blown engine

Both retired cars are for sale as is my w124 shop inventory

Perhaps you have the glow plug controller with the 'afterglow' function, GPs remain on releasing the starter, so you get the shake, rattle and roll when they finally turn off.

Some questions/ideas:

Is the compression up to specifications?

Has the IP timing been verified?

Were the re-built injectors 'pop' tested, and spray pattern confirmed, or just parts replaced? (Replacement parts have been suspect lately...)

All of the above could affect proper combustion, more so with a cold combustion chamber more than with a hot chamber.

Best Regards,
Jim

Thanks for your thoughts. The injector rebuilds did include the pop test and spray pattern testing.
Will start with the GP system, may be something there not operating properly.
The wife told me yesterday that she double cycled them yesterday morning when she had an early morning trip to make and she stated she felt she had less trouble. OK, why didn't I try that???
Thanks again, will post my findings.

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Den
1993 MB 300D 2.5
2001 VW Jetta TDI 5 spd.
2001 new bug TDI 5 spd.
Motorcycles

Check the thermostat first. Then timing and fuel delivery. If it fires right away after sitting then it's probably not fuel/air leak or glow plugs. The block doesn't heat up evenly and you're getting some (or one) cylinders that aren't firing at the right time as compared to the others - a cylinder will fire a bit "early" in a warm cylinder as compared to a cold(er) cylinder. If the thermostat is working properly and the timing and fuel delivery is OK then the issue is combustion air, but I don't know how your car is set up with emissions, computer, etc. May be something that modulates combustion air that isn't kicking in fast enough during warmup.

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daBenz - 1970 220D

Have the thermostat ordered, local dealers don't stock much, understandable.
Did let the GP system time out thru the afterglow cycle twice yesterday morning, started right up as usual BUT, she purrred like a kitten right from the get go, No shake rattle and roll and no smoke. hhhmmmmmmmmmmmm
Ever have a trouble free MB??

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Den
1993 MB 300D 2.5
2001 VW Jetta TDI 5 spd.
2001 new bug TDI 5 spd.
Motorcycles

my 603 was doing that... we finally found that i had no seals at the bottom of the injectors, installing them helped... didnt fix.. had them in and out several times finally discovered that the injectors were working loose on 1, 2, and 3 cyl. put locktite on them and reinstalled... problem solved... so far... not confidant it is permanent as weather is warmer now...... thoughts.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sounds like you need to look at your glowplug system.

Could be the glowplugs, but I doubt it as the glowplugs are being used to 'fix' the problem. Cold engine smooth, warmup rough, hot engine smooth again. Something is a little bit out of whack and it's seen as a rough warmup. Thermostat opening too soon, coolant passageways starting to clog up, timing chain starting to stretch 'too far', something in the fuel/air modulation not kicking in fast enough, a cylinder losing compression. Think of all these systems overlapping a bit, so one backs up the other. Over time one of the overlaps has gone away and the cylinders aren't warming up evenly.

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daBenz - 1970 220D

This sounds like the glowplugs are OK, I would not look here. It starts and idles smoothly, then misses, I doubt GPs are the problem

I also doubt the thermostat is at fault. Since the problem occurs between ambient and 60C, it would be expected to occur even with a properly functioning thermostat during its warm-up phase.

My guess still lies in combustion process. Perhaps the pre-combustion chambers themselves. Have you had a look at the pre-chambers for any obvious flaws, particularly broken/missing 'ball' at the bottom, plugged holes, unusual carbon build up?

It is still possible that timing is a bit late. Of course, compression could be a bit low, too.

Checking pre-chambers is relatively easy. Injection timing can be checked and adjusted, but I think it requires the RIV electronic device at the Dealer, which is the most precise method for this engine. They can also check compression while it is there, if you like.

Best Regards,
Jim