Oh no, not another smoke thread. I've searched the forum and tried different things but I'm still trying to track down my smoke problem. I have a new clue that I really don't understand so I thought someone here could shed some light on this mystery.

My car, 83 300D, turbo, automatic, smokes on cold start. Every morning a big cloud of white smoke announces to my neighbors that I'm at it again. It's really embarrassing, especially since I work in the environmental field and will have to get rid of my beloved MB if I can't get this fixed.

The smoke is WHITE, not black or blue. And it smells to me like paraffin. I don't use much oil and my coolant levels seem to be holding steady.

Here's the mystery part. The smoke begins seconds after startup (not immediately - there is a slight delay) and continues while I let the car warm up. I'm talking a big cloud of white smoke. Then as I drive off I leave a trail of easily visible smoke behind me. But it ends abruptly as soon as the transmission shifts to second gear. I didn't believe this at first but continued to watch in my mirror every day and it is without doubt the gear shift to second that causes the smoke to stop. This has been going on for months. If I stop at the corner and start again, in first gear, the smoke does not return. It is just at engine start up when the engine is cold. Ok, sometimes she does smoke on acceleration, pulling into traffic, etc. but it's never as bad as on cold starts.

What in the world is going on with the engine on start up that changes when it shifts to second gear? There must be something that changes, such as a richening of the fuel mixture, which causes the problem. Perhaps a richer fuel mixture and unburnt fuel is the result?

Also, I should mention that it runs really rough on start up but not any other time. I have changed the glow plugs and checked that they all work. They do, or at least did when they were checked. The injectors (spray pattern) were checked, too. Two were rebuilt but rest were fine. Actually, the problem has gotten worse since then.

Any help is appreciated. Surely there is something in the workings of these magnificent engines that I just don't understand.

Mark

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1983 300D 308,000 mi (Daily driver).

Mine does that if its around 35 or less degrees out, especially when its below 20ish. I'll start it and I get a maaaasive white plume, this past winter when I was brushing off snow amidst the plume, I noticed it didn't really even have a smell....which leads me to think it might have been condensation or something else burning off, as once the engine even slightly warmed up it would go away. When its warmer out my car only lets of an ever so small ash-based "puff" then its clear...but our 83, which we have come to a conclusion has an injection issue, blasts blue and white all over the place on startup. It also has three dead glow plugs, so it idles incredibly rough unless it is rev'd a couple times. When mine would let off the massive white plumes, it'd just do it more, WAY more, if I rev'd the engine at all, so I am not exactly sure what that is either. Yours might have an injection issue if it also idles rough, but I'd ohm test the glow plugs all again too to make sure they're all working. They can sometimes fail early and at random.

Maybe it stops smoking like that upon shifting because the load on the engine has changed, causing it to burn the fuel better?

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