I want to try install a MTX-L Wideband on my 1994 NA before going ahead with the MS3 Basic install just so I can get a feel for everything one step at a time. My plan is to cut the O2 sensor wiring just before the connector, replace the old O2 sensor with the new one, and splice in my MTX-L narrowband output to where I made the cut. Then after I get to my MS3 install, I can just cut the narrowband output and splice in the wideband output.

Here are my questions:
1) I believe my 1994 uses the 4-wire configuration which means there are 2 heater wires (https://www.flyinmiata.com/support/i...ire_sensor.pdf) . What should I do with the 2 exposed heater wires after I make the cut? I believe this will throw a CEL (not a big deal since I will eventually do my MS3 install) if I leave them taped off and not connected to anything, is there a proper solution?

2) Is it a good idea to use the ground wire (the white wire from the OEM 4-wire configuration) as my MTX-L ground? Others have stated that you can ground it at the MS3 itself or on the engine block, but does wiring my MTX-L ground to the white wire (original O2 sensor ground) achieve the same thing? This would allow me to avoid running an extra wire through the interior of my car to the MS3.

Thanks.

 

if you mount the MTX-L inside the cabin, how do you expect to run the sensor the header from there?

 

I've had issues using the oem plug for anything but the signal wire. Power and ground seemed to have issues. Someone told me the power is a 12v pwm possibly? So not always on. I dunno, didn't work consistently so I ditched it.

 

I was just going to roughly follow this guys video . The plan was to drill a hole in the unused rubber grommet in the drivers side firewall, run the O2 sensor cable, narrowband/wideband signal, and potentially ground through that hole into engine bay. Then I could leave the MTX-L gauge inside the cabin and have the wires all go to the appropriate locations inside the engine bay.

Is there supposed to be a power source in that OEM plug? This link says that there's just signal, ground, and 2 heater wires (which I'm wondering if I should just tape off and ignore a possible CEL).
OEM 4-wire plug (sorry the link was broken in my original post)
I was just going to attempt to find a wire in the cabin to splice for my 12V power.

 

yeah that video is exactly what i was hoping you weren't going to repsond with.

rofl.


wait to install the wbo2 with the ECU. use the supplied power/ground/input directly on the ECU connector to wire up the wbo2. install the sensor into the exhaust down through the shift boot.

 

Ok I'll probably wait to do it all at once. Unfortunately my old version of the MS3 Basic doesn't have the 12V power so I'll have to find a source for it elsewhere.