duty cycle readings on 87 300e

[richard28]

I have recently read on these posts that on the old 300e, esp 87/88, the cars have limited diagnostics on board, so I won't get the 70% reading with engine off, key in position. However, on my 87 300e & 88 300ce can I use the favored Sears multimeter I bought to adjust the CO to the 50% range, or is this done some other way? On my first try on the 88 300e, I seemed to have leaned the mixture based on the sound but the readings stayed at between 29-38% regardless of the direction I turned the screw (I'm assuming I actually engaged it, but this is the first time I did this, so I'm not positive). Thanks for your help.