Help! which O2 sensors? bosch but?# of wires?
Looking at ads for aftermarket O2 sensors, Some have good sales today for fathers day,but they often list multiple choices., even by Bosch. I have learned that part of the difference is whether
the sensor comes with a BMW electrical fitting. I am happy to splice the old fitting to save
But they ask two wire, three wire or four?
Does anybody know the difference? Are post and pre cat the same?
I have e39 01 and a 99 323, basically the m52tu and m54, same as a 330i.
Anybody know the big picture on these??
Or just where to get best price?