On my 124 300e I went to adjust the duty cycle at the adjustment tower and the duty cycle is stuck at aprox 90% no fluctuation very steady 90% ,also at higher rpm it is the same it only moves during throttle movement and floats right back to 90% and stays there.
SO I tried the adjustment and nothing even at a half turn rich and a half turn lean nothing but 90% duty cycle?
Then I disconected the o2 sensor and it went to 50% duty cycle but steady 50% no movement.I tested all this at operating temp including the o2 sensor which is at a fixed .053volts. Plug the o2 sensor back in and we are at 90% again.

Before I started the car I did the static tests with ignition eng off and it shows 70% duty cycle static.
depressing the airflow sensor plate gives us around 15%.
and full throttle gives us 24%
Mercedes wis documents show a non fluctuating 90% is current to EHA is implausible......... could I have a bad EHA or just wiring??????

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88 W124 3.0
96 R129 119eng
06 ML350
98 ML320 sold
02 CLK55 amg