Thanks for the suggestion, but you are one CIS generation ahead of me. This one is almost completely mechanical. There is no airflow pot and the on/off ratio does not indicate fault codes.

The electronics consist of a idle speed relay that manages an air valve to control idle speed, and a lambda controller that controls the mixture via the frequency valve.

__________________
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