CIS mixture problem?

After following the procedures for setting the mixture without a EGA, the following results were that I could not get the duty cycle above 40% using my dwell meter w/ 02 sensor disconnected. If I tried to lean it out, it idled rougher, richening it, ran smoother but no change on the meter. Am I missing something? Is there something wrong with the frequency valve maybe? 81'SC

The duty cycle is the frequency valve adjusting the mixture. With the O2 sensor unplugged, it is in a simple 'default' mode because it does not know what the mixture is (no communication from the O2 sensor). Actually, I think it (the default reading)should be 45 degrees but I'm not sure.

To adjust mixture with your dwell meter, plug the O2 sensor in, make the adjustment, then unplug the O2 sensor. The car will not obey the new mixture setting (if you choose to go richer, like 40 degrees or something) until you unplug the O2 sensor.



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'83 SC

so that means that the mixture can only be adjusted with the 02 sensor connected using the dwell(duty cycle) method? it makes sense.

Originally posted by Superman:
The duty cycle is the frequency valve adjusting the mixture. With the O2 sensor unplugged, it is in a simple 'default' mode because it does not know what the mixture is (no communication from the O2 sensor). Actually, I think it (the default reading)should be 45 degrees but I'm not sure.

To adjust mixture with your dwell meter, plug the O2 sensor in, make the adjustment, then unplug the O2 sensor. The car will not obey the new mixture setting (if you choose to go richer, like 40 degrees or something) until you unplug the O2 sensor.