1985-1998 [Subscribe to Daily Digest] |
When counting cross counts, are both the upward crossing and downward crossing past the 450 mV midpoint counted? Just wanted to make sure I'm counting the right thing-
On the idle speed trace I have, it looks like about 7 cross counts in 5 seconds, and about 12 cross counts in 5 seconds for the revved up trace.
If that's the case, then the idle speed trace is in range, and the revved up one is a bit low (if it should be 3 per second, or 15 in a 5 second period). If I'm only supposed to count a rich to lean crossing, though, the cross counts I'm getting is way low..
I was more concerned with the way the idle speed waveform looked, being so asymmetrical compared to the one like you show in your example, but maybe that's normal.
Always wondered about the function of other fuel system components in the speed of the signal toggling; the O2 sensor always seems to be the only component indicated when the cross counts are low or if the signal transition between the rich and lean states is slow. If the signal levels coming out from the sensor are okay, couldn't the speed of the signal transition be affected by the ECM or the injectors? I figured that would be the reason why it's able to toggle faster at higher rpms.
With feedback carb systems, the crosscounts per sec is lower than injector systems due to the slower control, but diagnostic paths for problems with the O2 signal only call for a new sensor. Would that be because the electronic control is much faster than the response of the sensor that it wouldn't be questioned? Have you seen any situations where something else could cause sluggish looking O2 signals?
posted by 64.63.223...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.