I am seeing if my friends car is running rich or lean. I have a aem wideband o2 sensor and gauge I am just plugging it into the end of the exhaust pipe. He had no exhaust leaks. Is this going to work rite? Or will it read funny?

If we pull out the stock o2 sensor and up plug it we get a code (normal) and if we leave it plugged in it just reads straight air.

So what method should I use? Should I weld in a new o2 sensor bung? Or will end of pipe readings work?

 

Thanks. What one is ideal ,new bung? Or is just pulling out the stock o2 with a code better? No cat but I didn’t think of that.
One other question I cant see any holes but dose this wideband sensor need a fresh air sample like some narrow bands sensors?

 

if you have the means, weld in a new bung for the wideband