my buddy bought a aem wideband......we wants to monitor the air and fuel on his stock scion,he wants to know if he could take out the 02 sensor on the downpipe and replace it with the wideband one,or does he have to get a second bunge welded in

 

You must have the primary 02 installed. Id recommend just welding in a new bung for it. Any exhaust shop should do it for around $20 or so. Alternatively, if you dont care about a CEL, or emissions, you can pull the second 02 sensor and install it there. The secondary 02 sensor is for emissions purposes only and everything will run fine with it removed, however it will show a CEL and youll fail an emissions test.

 

so thats the only thing that will happen if the second 02 sensor was replace is the cel...with the wideband one,emissions isnt a issue for him,as he knows people..i told him just to get a aftermarket downpipe,and just have the bunge aem, provides and have it wleded so this way hes not messing with the stock one..

 

Just get another bung welded, a lot easier and won't throw CEL's if you take out o2 sensors.