brillo

I finally ordered a stand alone wideband O2 sensor and I'm trying to decide the best placement for the sensor on my RP highflow cat.

I believe the conventional wisdom is to place it before the cat, but I'd like it to also last as long as possible.

thoughts?

Charles R. Hill

iTrader: (7)

Definitely place the sensor before the cat, as after renders the sensor useless for your purpose, and make sure the sensor is out of the way of any potential road debris damage. Route the wires away from any serious heat (remember rotaries' exhaust is much hotter than piston engines) and maybe consider following the wire routing of the front sensor along the top of the transmission.

dannobre

iTrader: (3)

You also want to place the sensor so that condensation doesn't drip into the sensor when the car cools off......ie above 9 and 3 oclock on the pipe. Ideal would be vertical...but you would have problems with the clearance....so you would need to go 10-2ish

mikeschaefer

Definitely determine sensor placement with the cat pipe installed on the car! I didn't do that and smacked my forehead when I went to install the sensor. Luckily for me the placement worked out perfectly. The wire tucks under the little lip on one of the smaller cross braces and then runs up under the shifter boot bracket, into the center dash area. The controller is sitting under my ashtray.

MadDog

I have mine in the expansion just prior to the cat. Haven't burned one in over 10k miles.

mikeschaefer

Mine is just after the shifter and every now and then after extending cruising (after reading the EGT thread I now understand why) my LC-1 will throw an error-2, which is sensor overheated/damaged. If I turn the car off and right back on it'll go away though. I've only had it installed for a few weeks too. =/

MazdaManiac

iTrader: (3)

I went through 1/2 dozen sensors before I moved it to a position after the mid pipe. Not a good place if you do have a CAT, though you can still use that position if you have an idea of the CAT effectiveness.
Not a good idea, though.
You can put an extender on the bung and a heat sink on the sensor, though I did that and it made no difference.

(Alan - I cleared my inbox)

brillo

if I'm under the car looking forward towards the engine on the passenger side, how did you angle the placement of the sensor? Dan said somewhere in the 10-2 oclock range, is that what you did?

brillo

wow, 6 sensors? All do to the heat? or was it something else?

MazdaManiac

iTrader: (3)

Actually, you want the sensor to be below the 3 - 9 o'clock range to dissipate standing moisture.
I installed mine at 3:30 after the CAT (looking from the rear).

Yeah, the heat was toasting them. The current sensor has been in for about 6 months in the post-CAT position.