Hello fellow brickboarders:

I have a simple but important question.

I have been pulling my hair out trying to get my 740 gl to pass emissions. I finally replaced the o2 sensor with a universal bosch 3 wire. The problem was that it has 1 black wire and 2 white wires. The installed sensor had 1 black and 1 red and 1 white. I figured I had a 50 50 chance of getting it right. The car ran flawlessly after install, but actually the nox emissions went way up!!!

Now (before o2 sensor replacement), after installing new plugs, cleaning the knock sensor, check hoses, replacing the fuel regulator, correcting the air box flap problem (its in the cold open position, i couldn't get the little thermostat to go back in!), my emissions readings are worse than when I started (but runs 10x better)!?

Is there some simple way to test that the 02 sensor is wired correctly?

Does the higher nox reading automatically tell me that it is not.
BTW, now I can't go back to nj dmv for another test, they told me now I have to go to a mechanic.

Thanks.