HI, If anyone can help me with this one:

I checked the duty cycle on my MB 300e 1990 with ignition on it's 10%
if I press on the air plate It goes to 45% if I go full throttle it is 79%
When I start the car it stays to 10% all the time.
Can anyone tell me why am I getting 10% all the time. it's not fluctuating at all. even idf I turn the mixture adjustment screw.

Thanks
AJ