Just wanted to give a heads up to hobby mechanics (like me) who screw up when setting their duty cycle. I have a 1987 190e. (pre error code)
My story began when my car started running a bit rough and developed a slight miss on idle. I read these forums in detail and addresed all the basics like replacing all old and cracked hoses and traced down a number of air leaks in the vacuum tubes. What happened next was the car actually started to run rougher and made the problem a whole lot worse. I replaced all other consumables like filters, plugs etc and stripped the entire injection system down into pieces and completely cleaned it out like new as it was a bit gummed up thinking this may have been the problem. All to no avail as the problem remained unchanged.
Then I thought I would go down the diagnostic route and investigate the voltages for each component. I purchased a meter with duty cycle and started testing all the voltages for all the components as per the manual. They all checked out fine.
Then I checked the duty cycle. It was way off. Great, I am onto something here. I followed the procedure and adjusted it back to 50%. The miss at idle was still there and after a while it would stumble and die completely, especially as it moved into 80deg range it would barely run at all.
After pulling the plugs I noticed it was running very rich and they were very gummed up. After cleaning the plugs, the car would run fine initially but shortly after they would foul up again and the car would once more stumble and die. I checked and rechecked the duty cycle and it was set correct, even in relation to the duty cycle at 2500rpm it was +10% at idle. It all seemed ok according to the book but I cold not figure out why it ran so rich.
Eventually I went back to basics and started from scratch, then I noticed that when the engine was off and ignition on, the static reading was 30% and not 70%as per the manual.
I reversed the cables from the meter into Pin 2 and Pin 3 which then gave me the correct 70% static reading. With cables reversed the duty cycle was of course way off. I then reset it back to 50%, recleaned the plugs and the car now runs better then it ever has.
So, the moral of this story is, don't always assume that the black cable from your meter goes to Pin 2 (earth) and the red cable from your meter goes to Pin 3 (duty cycle). Always check the static reading is at 70% before starting the motor and adjusting the duty cycle and avaoid the drama I had.
I can only assume that I was setting it way too rich causing the fouling and poor running condition. Perhaps in an earlier life, another mechanic had richened the duty cycle to compensate for air leaks in the hoses and vacuum tubing. Once I had fixed the air leaks it was then running too rich, with me adjusting it richer I was making it worse and heading down a road of pain.
I hope this information is of help to others in the future.