Hello all.
I have been measuring the X11 pin 3 signal in my 190E 2.3 8 valve (1992) to test the mixture setting.
I have noticed that, at startup, the duty-cycle is fixed at 50%, and as the car warms up, it decreases to 45% oscillating +/-5% or so. Until that, everything is ok.
But when I press the throotle to, say, 2000-3000 rpm, the reading decrease to about 25% +/-5%, indicating a rich condition.
Does this mean a problem or incorrect mixture setting? Should I correct this with the 3mm allen screw?
The measued values at idle seem ok (pre MB manual they should be 50% plus/minus 10%. I would check the oxygen sensor: disconnect it(just in front of the passenger seat under the carpet) and connect the signal male part of the connector going to the CIS to ground, measure the voltage at idle, should be more than .45 V, if not the sensor needs replacement.
Linear Mode
