I know this topic has been beaten to death. And i DO have read the immense amount of threads regarding this. But i still can't get i right..
My '86 300E, 178000 miles, is running WAY too rich. (~10 mpg)
Symptoms: Exessive fuel consumption, Exhaust smells of gasoline, Black soot from tailpipe, Black smoke under full throttle, and a strange 1 sec. 'surge' when i touch the gas pedal.
I haven't been able to get my hands on a multimeter with duty cycle, so i have only measured volts and miliAmps.
Warm engine - unplugged O2 sensor - measured 0,77V at idle and 0,81V at 2000 rpm from the sensor. (should be in range right?)
I followed stevebfl's advice to adjust the mixture to the lowest possible reading (volts) and got -0,1V..!
-engine still running well.
I reconnected the O2 sensor and measured mA at the EHA. -And the reading was all over the place. From -15mA to +10mA.
In the process i turned the allen screw about quarter of a turn CCW. So no matter what the readings say, the mixture must be leaner now, right?
What i DID get out of all this, was a jumping idle at 750 rpm where i had a steady idle at 500 rpm before.
I simply don't get it...