I'm really not sure what your doing, it's likely you have not given enough info here to give you any type of answer you need.
One thing is for sure, the stock ecu 'needs' a narrowband signal, you talk about bypassing it, but you can't bypass something the ech 'needs' to run properly, a car computer runs an engine based off info it gets from set inputs, take away one and generally it will fault or stop running.
Likewise you bought a wideband for tuning?, but what are you trying to tune?, using what, doing what, in what way, because as far as I know you can't really tune the stock ecu.