4 replies to this topic

[24vDiMo]

My car is making a slow transition toward SM. Just doing HPDEs for now to build toward competition license.  I'm new here.

About to install a Kooks SM exhaust, but it delivered without the post cat O2 sensor bung. I've been running a test pipe with my otherwise factory exhaust for years with an anti-fouler/O2 sensor extension tube. I planned to transfer this setup to the new exhaust, but here I am, bungless. Without bung.

I'm reading that lots of the spec guys will zip-tie the sensor somewhere under the car, to the cage on the interior, or under the hood in some cases. It needs to be grounded. Boom, sensor warms up still, and doesn't see emissions. Reports cat is OK.  Most of this advice is for NB Miatas.

Further reading suggests that the 97 ECU does things somewhat differently from the NBs?

Anyone do anything clever with their second oxygen sensor on a 1997 here?

[24vDiMo]

Could anyone clarify where they're mounting their second o2 sensor.  Fabricating a 90 deg bracket to mount it to the package tray sounds like the simplest solution.  Sensor on the inside or under the package tray?  Isn't that a little close to the fuel fill neck for a heated sensor?

[Ron Alan]

Just past the downpipe to exhaust/midpipe connection.

 

Opps...you are referring to stock...NM

[bmarshall1]

I bought my car used and found mine stuffed into a interior panel hole th the rear of the driver's door.  Not sure if that's proper, but that's where it is.  I occasionally get a CEL light but have ho idea if that's the cause or not.

[24vDiMo]

Here's what I did. 

 

 IMG_6559.jpg   239.99KB   1 downloads

 

Used a step drill to open a pre-existing hole in the package tray.  There's a bung/nut on the underside that I was going to weld, but I trashed my last welding tip over the weekend.  Ran the wire through the existing wireway and up through a hole near the factory seatbelt reel position.  Neat and tidy, no CEL.

 

A major concern was how hot a heated O2 sensor would get.  I couldn't find an answer anywhere.  It gets warm at best in my experience so far; maybe 90-110F.