To refresh, stalling on quick stops prompted me to research why the frequency valve had been unplugged. I found with the help of members here, especially ctaylor (thanks Chuck) a bad ground (at the connector) on the warm up compensator. I was totally frustrated to find I still had the original problem, so I got back to basics and pulled a spark plug, (as another member mentioned, but I was stubborn) and found a basically new plug to be badly fouled...rich mixture. I figured this had occured with the WU comp out, so I cleaned them and was going to check gap, since I didn't remember gapping the plugs when I installed them. Unable to find gapping specs in my owner's manual, I came to this forum, my new home on the internet , to find spark plug gap as recommended by our members.......and found the threads about platinum plugs, which is what I installed when I bought the car . I promptly put in a fresh set of Bosch W9CD Supers and I'm happy to report the SL is back! Fast idle cold, no hesitation, though the on/off stays at about 15%, it seems the controller has gone to controller heaven, as it doesn't change with engine temperature. Regardless, happy camper here. A big hearty thanks to everyone here for their generous help.

Paul

I have twp further suggestions.

First. Disconnect the oil temp sensor, and ground the lead. Then start the engine and see if you get a 60% on/off ratio. If you do, then the brain is at least alive and you may have another problem in the system.

Second. If you are going to drive the car with the lambda system inoperative, get someone with an exhaust gas analyzer to adjust your mixture to be sure of the basic setting.

__________________
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

Will do, and I'll let you know the results. Thanks, Chuck.