I tried the procedure recommended here on my 1982 280e. I used pin no. 2 of the diagnostic connector, but found that I could not get the voltage below about 8.2 (not in the same range as for georgehifi's 300e. Has anyone tried this procedure on a 280e. BTW it has a O2 meter, but I don't know if it is working. Also, I find that after making the mixture adjustment, I had to crank the idle all the way down to the point where there was no idle adjustment left (all the way clockwise).