Frequency valve

["chris " <chris@xxxx>]

Hi list/DMC joe

I was reading a manual published by Bosch, which covered K jetronic, 
which said the frequency valve recieves a constant 12v feed and the 
ECU pulses the ground. If i connect a voltmeter across the terminals, 
i should get a pulsing 12v? correct?. If there is 12v across the 
valve, if i connect 12v direct i should be able to feel/hear the 
valve clicking?. When the valve has no power i assume it is shut, 
which mean if its not working the engine will run rich? Could this 
cause the cat to glow red?

If there is not 12v at the valve I should check 12v at the lamda 
relay which runs to the frequency valve? and continuity of both 12v 
and negative from the ECU to the valve?

If the Lambda sensor is not working or disconnected i assume the 
valve just work as it should when could on a fixed ratio? This should 
eliminate the sensor if its causing a problem?

Thanks

Chris Vin 16327