I also forgot to mention check the transmission oil level carefully by mercedes recomendation. . Unfortunatly if it were a transmission causing this when cold It might be hard to isolate.

Although a really dirty transmission filter and thick cold oil could starve the transmission perhaps. I am not suggesting you run out and buy a filter at this point just somenthing to keep in your mind.

I was kind of wondering if it was a really outside possibility the last time I posted. A couple of years ago I had some funny symptom that I do not remember now. I do remember that for a little while I thought it was the engine. It was caused by low transmission fluid in the 1984 123. Not a lot either. Once again it only takes a minute to check the fluid level with the engine warmed up.

I believe only the 85s have the temp controlled switchover valve. The valve you are talking about is controlled by pressure from the manifold.

__________________
'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles

Just for avoid future miscommunications, The large bolted-on canister fuel filter is called the secondary filter. What you're calling the pre-filter is referred to as the primary filter.

I have no good diagnostic hypotheses. Maybe posting a video of it's behavior might stimulate more creative analysis.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

No.

Ask your "expert" what mechanism enables said capability.

You're making the assumption that slightly less oxygen will result in less work being done by a (several) cylinders.

This is not a gasoline engine.

The engine has more than enough oxygen under all operating conditions with the exception of maximum torque, where the oxygen should just match the available fuel.

The slight decrease in oxygen due to the EGR will have a very limited effect on the work done by the individual cylinders.

The only other possibility is if the EGR is wide open and significantly lowers the available oxygen in the cylinders. In such a case, the engine probably won't idle and might smoke heavily at idle.

I have very happy yet embarrassing news.

First, I did have an algae problem, that thankfully has been cured by an initial boiling of the tank, then further washings of the tank. I think I had that tank out 2 or possible 3 times. Also, I have put more fungicide in there than I care to imagine. That stuff is so expensive at $25.00 a bottle, and I am sure I used at least 3 bottles over the last eight months. However, I am prolonging getting to the embarrassing part.


I basically misinterpreted the facts based on the evidence of the grimy fuel filters. To the driver, when you stomped on the pedal while cold, the car just wouldn't go faster or sometimes would buck back and forth as the car would get power then lose it. My first mistake was to confuse 'unresponsive speed' to 'loss of engine power." Upon closer examination of the facts, when the car 'lost power' (like staring out the back window to see lots of smoke and looking at the tachometer which would race high) it became obvious that the engine was getting more than enough fuel. It finally dawned on me that I was not having a fuel starvation problem, but transmission was slipping. Ughh.

More embarrassing is that I must have cause this. About almost 2 1/2 years ago when I first got the car and serviced the the transmission (drained fluid and changed filter) I must have never put enough ATF back in there. It is most unlike me to do so, and I am having a hard time believing it, but since I never saw any transmission fluid on the ground nor does there seem to be any in the radiator reservoir, the only remaining culprit is my failure to fill the transmission with the correct amount of fluid.

Well adding another ~2 quarts of ATF Dex IV did the trick. Car runs perfect when cold in the morning now. Hopefully I did not take to many years/miles of the transmissions life

Hope my mistake can at least help others.

Shoot, Barry!! I didn't re-read this thread and never say your post back in November!!! I could have solved this a 2 1/2 months ago!