Apex1.0

Does the voltage of the factory O2 sensor indicate anything about the A/F ratio? I know a wideband is the only reliably accurate way to A/F tune. But for very basic tuning can narrowband voltage be correlated to an A/F ratio, in a general sense?

I am not talking about high risk applications like FI, just basic rich, lean or richer or leaner applications? So the voltage range of the factory O2 is .001-1.00 volts. We all know the sensor is very accurate at stoch 14.7:1. My understanding that is around .495 volts. So that means higher voltages indicate rich and lower voltages indicate lean.

So I have a stock 00. Once up to temp and I go into WOT, the ecu commands open loop and the front O2 reads .955 volts pretty much all the time. I added a test pipe and with no other changes, under similar conditions the WOT voltage is .865. This would indicate the mixture has been leaned, correct? By how much we are not exactly sure, but we know its not near 14.7:1 at .495 volts.

Anyone use narrow band voltage to tune?

Ian300D

No one does. And ECU doesn't read 02 that way either. Read this, and if you really want to waste more money than a wideband to read narrowband.

https://sites.google.com/site/chrish...reference_page

Long story short, not worth it. NGK wideband (best there is), is under $250 shipped.