Steve,

Thanks, all is clear now. I was stuck on the apparent disagreement between your scope diplay and duty cycle readings versus what I was measuring on my vehicles. Obviously if convention in modern automotive electronics is to control on the ground side rather than supply side, then duty cycle referenced to ground will be inverted. I was amused that you noted that control of D-Jet injectors (being on the supply side) was an exception. I guess I would hardly consider D-Jet "modern". As advanced as it was in its day, it seems prehistoric now with its use of germanium rather than silicon transistors in sections of its electronics. To give it credit though, I am amazed that after 31 years and some 350,000km, that same system in my old 350SLC soldiers on with only one transistor failure in the 21 years I have owned it.

Getting back to the KE system on my other two cars, the clue is as you suggest, to ensure that for KOEO I am reading 70% rather than 30%. I was unaware that 70% was used worldwide except California, thanks for this useful advice.

As Pesuazo suggests "you must be the most educated car mechanic". Steve, if more mechanics used your well considered diagnostic techniques rather than simply throwing expensive parts at the car, then I'm sure there would be fewer dissatisfied customers out there. Pesuazo, I think the only correction that should be made is to refer to Steve as a technician rather than mechanic as his knowledge is what makes the distinction.

Thanks for taking the time to reply and again, thanks for sharing your wealth of knowledge on this forum.

Greg

__________________
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.