O2 location on OBDII mid-pipe for 95M3

[m3f_das borgen]

Yep that's the spot. (RedX)


It won't clear the bottom of the car on the outboard pipe. Says I who has a bung and plug there...Lol (I was inking of putting the wideband there. I didn't check that b4 I welded them both in)

For shame!

[m3f_YAOG]

Here we go.....



I decided to put the O2 sensor in this area on the 96+ midpipe (note red circle, NOT white markings):

I put mine in about the stock location (about where the red circle is) positioned as vertical as possible like the OBDI pipe but at enough of an angle that still allowed me to get the O2 sensor in and out without dropping the mid-pipe. Tie wraps will keep the excess wire from burning or getting caught and ripped out by road debris. Also, don't forget that you need to buy good stainless steel plugs with copper sealing rings for the unused O2 OBDII bungs and use a LITTLE good German copper or silver based anti-seize paste on the bungs. DO NOT USE anti-seize on the O2 sensor or anything upstream of the O2 sensor or you may kill the O2 sensor.



My car was tagged as a gross polluter, apparently because the OBDI M3s are known to have very high emissions due to all of the dead cats in the OBDI M3s. I have been required to go to a STAR testing station each time the M3 needs to be smog tested for registration renewal. I understand STAR testing stations very strictly follow California state testing procedures. I watched as the tester used a rolling chassis dyno with a better/faster sniffer and the testing system reported directly to the state computer system before, during and after the actual emissions testing. Creepy if you ask me.



Anyway, the update to an OBDII M3 mid-pipe worked like a charm on one O2 sensor. With a new O2 sensor installed my 240,000 mile OBDI M3, the car passed California STAR smog testing station with flying colors. The engine also seems to have more power through the mid-range and upper RPMs and as a bonus sounded much better with the stock rear muffler section. Now I don't have to cut open that spare stock M3 rear section and modify it to open up the sound like I was planning to.