A couple O2 related questions

[Numbchux]

I got the definitions and cable figured out to monitor and log my 1992 CPFI Chevy 4.3 engine, and it's awesome.


My definition shows the O2 sensor signal in mV. Is there a way to change the conversion equation and such to show it in relation to the actual air/fuel ratio?

The current equation is "X * 4.440000 + 0.000000", if that helps.



Next question. Check out this graph I took of the truck running this afternoon:


Black is rpm, blue is TPS, green is vehicle speed and red is 02.

That can't be normal. Is that just a result of a bad sensor? Or something else?

[robertisaar]

narrowband O2 sensor. while i have generated a decent table for converting narrowband mV into AFR, there's no guarantee of how accurate it actually is.

and that might be a bad O2 sensor. it is swinging a bit(which is good when operating in closed loop), but not at any kind of normal pattern.

what's it look like when crusing at ~55MPH?