majurellc

I have a 1994 S350D that has sluggish acceleration about 10 minutes after it's started. It accelerates normally after initial start up but just drops power by 30 to 40% after you get going. It's almost like the turbo stops engaging or at least has about the same lack of power affect. It seems like something gets switched off because nothing else is affected but the acceleration/power.
I've had the fuel tank drained and flushed and all filters replaced, including the screen one in the tank and it had no affect. It doesn't smoke excessively when this happens and no check engine light is ever lit. It seems electrical because when it's shut off for a few minutes it takes off with full power for about the same length of time. I've owned several different Mercedes diesels and none have ever done anything like this before. Hope some of the experienced Mercedes folks here can help lead me in the right direction. Many thanks in advance.

fuga28

air mass sensor maybe?

majurellc

Worth checking out, thank you. It also affects the shifting... winds out to higher rpms before shifting so it shirts much harder. I'm trying to get some leads before I go to the dealer or local shop and they spend days trying to locate the problem. Locally they tend to change everything until they finally actually find the problem... gets expensive letting them learn/troubleshoot on an hourly rate.

fuga28

Check all the vacuum tubing as well. I remember that 250D Turbos and 300D Turbos if they had any kind of leaks in the vacuum system, the turbo wouldn't work.

majurellc

Will do. At least it's a start and hopefully in the right direction. I appreciate the suggestions my friend.

fuga28

You're welcome

gdparki

I have a 93 doing the same thing. did you learn what the problem was yet?
Thank you

majurellc

Situation is still the same. I was told that since the oil level light is on that the turbo might not be coming on thinking that there was not enough oil to lubricate it. However I have no one to verify that and the sensor has been replaced but the oil light still remains lit. At this point I'm letting it go for about half what it's worth. It's one of the prettiest W140s that I've ever seen.