Frequency Valve Operation Question

[phebbler]

Is the Frequency Valve normally closed when no power is applied?

I unplugged my Lambda ECU completely and the car still runs and drives.

How is this possible when the default duty cycle is 45-50% on the Frequency Valve. Does it have some flow even off in case of failure?

Thanks

[82DMC12]

I think the valve would be closed if it is not energized. The function is to modulate the control pressure based on CO readings at the lambda sensor. Your car will probably still drive without this modulation but your gas milage and tailpipe emissions will suffer. You still have basic control pressure even without the frequency valve. I bet your exhaust smells bad?

Andy