Connecting wideband (LC2) to 4 wire o2 sensor
 

Question: when connecting a wideband output signal to the OEM 4 wire o2 plug, which wire should I splice it into? The OEM plug has: black, black, blue, white.

Bonus Question: Are the remaining three wires used for anything, or should I just tape them off?

i would think this is a very common thing and would have been answered all over the forum, but I can seem to find it.


Details: I have a 99 running a DIYPnp and a LC-2 Innovate Wideband. The gauge seems to be reading fine, but TunerStudio just reads "10afr" at all times and obviously isn't getting a proper signal. I'm currently using the BLUE wire to provide signal and have the other three wires taped off. I suspect it's the connection between the wideband output wire (yellow on this model) and the OEM o2 connector.


Thanks!

I'm doing the same thing to my '97. You need to search. I found what I was looking for by searching, a wiring diagram, and 1 PM sent to a member who had done it. Good luck!

I made mention of not being able to find what I'm looking for. Possibly I'm using the wrong search terms? Or missing the answer? In any event, thanks the totally cryptic and useless response 😊

I'm not sure what the stock o2 sensor was in a 99 Miata (or mine for that matter), but I found a bunch of promising links with the following search:

https://www.google.com/webhp?sourcei...r+pinout+miata

What i did

Tap into the factory harness for the signal wire. This help to retain the factory o2 for narrow, incase you ever need it.


Then follow the rest of the installation instructions. They arent wrong, but can be confusing to a new guy.
lots of help on the web too.

Have you set up the o2 in tunerstudio?

http://www.miataforumz.com/1990-200-...ring/99sys.pdf


Page 10

I have the yellow signal wire of the LC2 connected directly to the blue wire of the OEM o2 plug (that I cut from the OEM narrow band)

I have the LC2 grounded under the dash, but now I'm considering also splicing it into the OEM o2 plug since that also has a ground.

As far as the tunerstudio, I have it set to wideband and have it set to LC2. I can't recall the details or menus since I don't have the comp in front of me.

Clarification: The two setting in tuner studio i made sure to adjust:

1. Under File > Vehicle Properties > Project Properties > Settings > I set the "Oxygen Sensor / Display" to "Wideband (Default).
2. Under Tools > Calibrate AFR Table > I set "EGO Sensor" to "Innovate LC-1/LC-2" default."

I don't believe i made any other adjustments to account for the wideband.

Next, the wiring diagram everyone's been sending is for the receiving side of the under-hood O2 connect. Tonight i tapped into this (again the BLUE wire), and still don't get a signal appearing in TunerStudio. TS shows 7.4AFR without moving.

Just to close out this thread:

My DIYPnp was wired to receive the o2 input signal from the options port. I spliced o2 signal wire into my DB15 connector at pin 4 and started getting a signal right away.

That said, I tried every combination of grounds and still can't get the gauge and tunerstudio to match readings, but that's for another thread.

Thanks!