W201 190D - Engine Problem

Hi!
I'm an owner of a 1991-built 190D (75HP) with now 180.000km. In the last few weeks i'm having a problem with my engine:
Every time, i start it cold and drive up a hill behind my house, stop
there at a traffic light it seems to run only on 3 or 2 cylinders. The engine is stuttering (but it does'nt turn off). When i push the accelerotor pedal it works fine, although I think it's a little bit "nailing" more than normal at this time. When I drive then a few hundred meters and stop again, the engine is working fine.
When i start and drive on a flat street (need no high power to get up the hill) it works without problems. Also when the engine is hot and i drive up the hill, it works fine.
At the repair station they didn't know what the problem could be. They told me to try changing the valve that prevents the fuel to return to the fuel tank from the injection pump. But unfortunately it didn't help.
Did anybody have a similar problem with that engine ? Apart from that problem the engine works fine. I do not have any problems with the power of the engine.
Thanks for suggestions!
Daniel
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It appears that your engine isn't firing well when it's cold. Either a glow plug is kaput or one cylinder has low compression.
If the engine starts quickly when cold and immediately runs smoothly the glow plugs are OK but if it misfires when first started a glow plug is defective and should be replaced. After the engine warms up the glow plugs are no longer a factor in its operation.
A compression test will quickly find a cylinder with low compression. Then the reason for the low compression must be found. A valve that doesn't fully close, worn piston rings or a broken cylinderhead gasket are the usual possibilities.
Incidently, compression is tested via the glow plug holes so if you have the compression tested have new glow plugs installed - the labor is zero so the extra cost is only the plugs' cost.
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Hi T.G.,
a few months ago i had a cold start problem, so i replaced all 4 glow plugs and the problem was solved. Now the engine starts fine when it's cold. As i said, i have no problem with the power of the engine. The car accelerates fine and the top speed is reached without problems. Can it nevertheless be a compression problem?
Greetings,
Daniel
T.G. Lambach wrote:

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Daniel, the only way to know the engine's compression is to test it.
If this engine has mechanically adjustable valves they should first be adjusted - before a compression test is done - for a tight valve could not be closing fully and so allowing compression to escape.
Diesels are compression engines and their problems usually emerge when the engine is cold, not when the engine is 80 degrees C.
The problem you describe is a symptom, your task is to find the cause.
Tom
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Does this engine have some device to give it a slightly higher idle when the engine is cold? - like an automatic choke or cold start circuit on a gas engine?
If so, I'd check it before doing anything else.
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