A narrow band sensor is designed to read "richer than" or "leaner than" stoichiometric (lambda 1.0, 14.7:1 AFR on gasoline).. Trying to get an accurate 'wide band' (eg, linear) response from one is highly unlikely.

A narrow band sensor is what is used on all cars since 1992 (with the exception of some running bosch lsu4 pseudo-wideband sensors) to do closed-loop fuelling. You can use it for this too of course, as long as you only want your closed-loop to give you lambda 1.0! Otherwise you'll need a proper wideband kit.. as long as your ecu supports this.