brewtoo: ... A few months ago I adjusted the lambda and now it gets almost exactly 27.

What did you mean by the adjustment of the lambda sensor? The replacement?
How can I adjust the lambda?
Thx.

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1987 MB260E 187K

Modern emission controlled cars are pretty consistent on actual mileage, but there is a lot of scatter in owner measured data. In order to have accurate readings one needs to record gallons and mileage at each fillup and look at the average of lots of data.

Also, odometer error has a big effect, such as when the car has shorter than OE tires. I have measured odometer error data on my car, and it reads 2 percent high with the installed tires, so my corrected data is two percent lower than the observed data.

The EPA numbers on my car were 18/26 and over the long run the actual averages are pretty close to this. In heavy urban driving mileage is in the high teens, low twenties in a mix of urban and freeway, and mid to high twenties on highway trips. I've recorded a couple of legs over the years at a little over 30, but they were slow. Mileage definitely drops off with higher average speed.

Since my car is a five speed with a 20 percent overdrive relative to an automatic and has no torque converter loss, the highway mileage rating is 1-2 MPG higher than an automatic as I recall. An automatic W124 with a 2.6 or 3.0 liter engine will probably be one to two MPG lower than my car in town and about the same as a 190E 2.6 automatic on the highway. The W124 has a slightly lower drag coefficient, but is offset by slightly higher frontal area.

I looked around for the EPA mileage data on other '88 models, but, sorry, I don't have it. It might be on the EPA web site.

Duke

I drove a 94 E320 from Dallas to Fairfax, VA last November. Used cruise control as much as possible, never exceed 80mph and averaged 29mpg for the trip. I was amazed. Commuting daily between Fairfax and Bethesda returns about 21mpg.
Mark

Do a search on that. There's tons of info.

And Duke, my odometer is off, too. It reads 4% low. I allowed for that.

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2012 E350
2006 Callaway SC560

brewtoo,
are you talking about the adjustment of fuel/O2 mixture ratio? Or, you can do something particularly to a lambda sensor excluding a replacement? Thx.

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1987 MB260E 187K

http://www.fueleconomy.gov/feg/findacar.htm

1987 Mercedes-Benz 260E
Fuel Economy

Fuel Type Premium
MPG (city) 19
MPG (highway) 23
MPG (combined) 21
Annual Fuel Cost $1378

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1987 MB260E 187K

I didnt hear about lambda adjustment.Here they adjust the %vol of CO.by inserting a pipe to the exhaust.Anybody know what is the proper %vol of CO???

Sounds like you're in Europe. In the States the percent CO is whatever it takes to pass field emission testing. For a properly running M103 it will be a small fraction of a percent AFTER the catalystic converter, so a little higher out of the engine.

If the KE system is functioning properly the engine out CO with an average stoichiometric mixture should be something under one percent.

Duke

My car dont have catalyser and the %vol CO is 0.77 Is it ok?or should be more??

Less than one percent CO on a KE system with no catalyst indicates it is operating close to stoichiometric. If this is sufficiently low to pass local emission testing (if any), then it should be satisfactory.

Duke

I wanted to confirm my earlier mpg report with a trip I made yesterday.
I filled up right-up to the gas cap before leaving.
Did 287.6 miles, mostly all on speed control at 65mph on a relatively flat highway. (no city driving). No special driving technique was use to maximize mpg, just normal driving.
When I came back, I filled-up again a the same pump, at the same service station, at the same level.
result : 29.92mpg
With 390K on the clock, I think it is not too shabby.
jackD