W114 ECU problem?

I'm wondering if anyone has had a similar problem to this one. I've just spent the day testing and retesting my 280e for running rich and fouling up the spark plugs. The air and engine temperature sensors test good until I turn the ignition on, when I read an open circuit on my dmm. The signal circuits test correct all the time but for some reason the earth at pin 11 goes from almost zero ohms to 15, and  pin 13 goes from zero to 24 ohms as soon as the ignition is turned on. Everything else checks ok and I have correct fuel pressure and the injectors all seem ok. Power and earth's are all good of course. Any ideas what the problem could be?

Hi Unknown from DownUnder,

you cannot measure Ohm and switch on ECU at the same time. You will have overlay of voltages which correctly confuses yoru DMM.