87, 68K mi, smooth & powerful, but smokes on boost (fine, white misty smoke).

Has clean filters, trap ox service campaign was recently performed, uses synthetic oil (doesn't burn any), no oil/coolant leaks, and am using Redline 85+ &/or Dr. Diesel.

Have been told that improving injector spray pattern might help (expensive) or retarding timing (loss of power).

Ideas? How about some way to make it run leaner? Or are there other additives that suppress the smoke?

Thanks. Don't want to be shot by a treehugger.

I got advice the other day to "Italian-tune" my new-to-me 300 SDL when I mentioned that it smoked a little at full throttle.

I drove it to work yesterday and did just that: I floored it and ran it up to about 90 MPH on an long, uphill section of the highway on my way to work.

By the third time I did this, it not only no longer smoked, even at WOT, it seems to idle smoother and run quieter.

I got the advice from a serious MB Diesel owner who has five of them. He said they like to run hard and you need to do this pretty frequently to get all the carbon and soot out if it isn't driven on the freeway regulary.

Well, it is driven on the freeway daily, but it is in stop and go commute traffic I'm afraid. So, I'll be adding these "Italian tune-ups" to it's schedule every month.

This is a tricky situation. The Italian tune-up can blow these up if the carbon has collected around the EGR area. I have seen many do this. You could have someone play with the timing or the fuel mixture, but your power will decrease with smoke decrease.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

quote:

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Originally posted by Benzmac:
This is a tricky situation. The Italian tune-up can blow these up if the carbon has collected around the EGR area. I have seen many do this. You could have someone play with the timing or the fuel mixture, but your power will decrease with smoke decrease.

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How does one mess with fuel mixture? (I'm told a chip handles that). This seems less invasive than a timing change.

What exactly happens when carbon builds up in egr area and the car is "italian tuned"?

Apparently, "italian tuning" was exported from Italy to Germany. One mechanic who used to work at a Benz dealer told me that the unofficial prescribed Benz method to "clean out" the trap oxidizer was to run in a low gear at high rpms for a few minutes on occasion (I forget specifics) - this would heat up the t.o. and unclog it. He said none of the salesmen could ever bring themselves to tell a prospective/new customer to do this, and the rest is history.