We both must not have been reading each other here. Since what you just said is the same as what I did! The lamda tower adjusts the base mix and the EHA adjusts to keep it where it is supposed to based on the temp snesor and O2 and position of the AFM plate via that sensor on the side of the AFM. All done via the CIS-E Controller.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Just to summarize and allay any possible misconceptions or confusion for readers of this thread, the basic mechanical mixture adjustment will not make any difference in warm engine operating characteristics, including fuel economy, as long as all KE system components are in good working order, including average duty cycle readings at idle and 2500 that are within 20-25 percent of each other.

The basic mixture should only be adjusted if there is a significant difference in average duty cycle at idle and 2500 RPM.

If adjustment is deemed as necessary, adjust the idle duty cycle to a little under 50 percent at idle. This will provide a slightly rich basic mixture, which should provide good starting and warm up driving characteristics.

With the idle duty cycle a little under 50 percent, the 2500 RPM duty cycle will probably be a bit over 50 percent.

Duke

P.S. I pulled my window sticker out of the file and found that the EPA ratings are 18/26. I corrected my previous post. Recall that my car is a five-speed and the autos probably have lower highway mileage. You can look at the EPA web site for the auto trans EPA mileage numbers. These cars were not economy champs, but technology has steadily progressed to a point were a modern sedan that is 500 pounds heavier and has at 50 percent more power has higher EPA numbers.

A note also to anyone reading this thread. The %50 only applies to KE-III systems! My 1986 190E 2.3 8V has a KE-II system in it and uses a hair diferent method to set the Base Mixture using the Lambda tower. In the W201 body at least the CIS system was updated to KE-III for the 2.3 16V and the 1987+ 2.3 8V and 2.6 engines. So if anyone reading this has the KE-II setup then the mixture needs to be set diferently. With that you unplg the O2 with the engine running and at temp and take the reading at the X11 connector at pin 3. That is you base voltage, then you plug the O2 back in and set the Mixture to the base voltage reading you got previously, or there abouts, as it will wander up and down as it should. If memory serves me the voltage should be between 2.1 and 4.8!

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Thanks for the help guys, I think that I will just leave well enough alone.

I have never had gas mileage as good as mentioned above. My car could not break 30 mpg going downhill with a tail wind. The best it has ever done (and only once) was 25 mpg under almost perfect conditions on the interstate a few years ago. Typically, I get around 17-18 mpg back and forth to work. During the summer, when school's out and the traffic is not as bad, I will average 19-21. With mostly highway driving I will get 22-23.

Not very good for a light 3000 pound car with a little 2.6 liter 6 cylinder that doesn't even have very much power. With premium gas well over 2 bucks/gallon now, mileage is more of an issue than it used to be. Just another little factor to add to the high price of ownership to keep the old Benz going. So for now, I'll keep paying.

Thanks again,

Wayne

That is one thing I like about my 1986! It uses Regular due to its KE-II and CR of 8:1! Of course the gas mileage with my lead foot and its whimpy 120Hp does suck, but still is like 20MPG. My W203 though has been getting crappy mileage this winter due to me not normally driving it and now I am and I love the added power and always floor it! Oh well, life goes on!

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....