Try this.

Disconnect the and ground the wire from the temperature sensor on the oil filter housing. That should put the system at a 60/40 or 70/30 duty cycle. Let the car warm up fully

Then test the voltage between your new oxygen sensor and ground. See if you can adjust the mixture to get a .45 volt reading. Then reconnect the temp sensor wire and see what duty cycle reading you get. Higher, go lean and vice versa.

BTW - you are changing the mixture, aren't you? You need to push the hex key down against the spring and feel it engage the adjuster. Sorry, I had to ask, it's easy to feel like you're turning the adjuster when you're not.

__________________
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