What I meant is that you cannot adjust the mixture because the computer is reading the output of the oxygen sensor, and changing the enrichment. So if you richened it with the adjustment, the O2 sensor increased its voltage,and the computer responded by leaning it through changing pressure in the fuel distributor. You can only change the mixture if you go far enough either way to completely override the electronic system, which is a bad idea.

So the way you adjust the mixture is to set it at hot idle so that the on/off ratio is about 45%. If you have any doubts about your O2 sensor, replace it with the appropriate Bosch generic.

Look toward the end of th first page of this thread for my version of how to adjust the mixture:

http://sl107.com/groupee/forums/a/tpc/f/2346035941/m/8251096042

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe