Hey Guys,

My 300E has had a slowly worsening case of the SSS lately. I have also noticed that my idle is a bit low (+/- 550rpm) and had suspected a lean condition causing this (my milage has been a little too stellar of late: 26-27mpg highway... ).

I just got done checking & re-checking my duty cycle with the following results were:

(All numbers below are approximate and do oscillate w/ car running. Test was done with car @ operating temp, Neg in PIN #2 & Pos in Pin #3.)

Duty Cycle with engine off - 50% (6.03V)
Duty Cycle with @ Idle - 90% (+/-1.2V)
Duty Cycle @ 2500rpms - 65% (+/-4.2V)

From what I can understand on the subject, my DC should be 70% w/ engine off for a Federal car like mine and the 90% DC @ idle indicates an incredibly lean condition. ()

What would cause the DC to be low with the engine off? Am I looking at a component failure (throttle switch sensor? crank position sensor?) or is my DC just way put of adjustment?

I have read up & learned tons on DC/Lamda function, but I have seen absolutely no mention of the DC being anything other than 70% w/ the engine off...

Thanks!

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Currently:
1972 350SL Euro 4spd
1973 BMW R75/5
1981 BMW R80GS
1995 FZJ80 with OM606 Conversion In Progress