installing my Aem wideband sensor in my miata, and im stumped on where to get the sending signal (white wire on the wideband harness). i already tapped into the power and ground in pins 4a and 4b near the ecu connectors.

for the signal wire, ms3 mini documentation says GREEN/RED wire.
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Flying miata says LIGHT GREEN/RED. https://www.flyinmiata.com/support/i...gauge_type.pdf
and my friends say BLUE/RED from the front heated o2 sensor harness.

which one do i use???

 

Green/red wire is at the ECU Harness, I spliced into that wire close to the connector and the signal worked OKish at idle, got sketchy when driving around. Pretty sure a ground somewhere was bad and causing that issue though.

 

When i was looking at the wiring diagram, green/red goes to the instrument cluster and lightgreen/res goes to egr valve. Does this sound right for the wideband install?

 

Not at all, it was labeled as a signal wire on the OEM diagram I believe, for a 1.6 NA. Not sure what miata you have

 

apologies, i have a 96, na8

 

On a 96, it's red/green. On a 97, it's blue/red. In both cases, it's on the middle plug, pin C (top row, second from right).

 

The middle connector on mine has a light green/red and a blue/red, the lightgreen/red goes to the egr valve, and the blue/red is one of the 4 wires that go to the front o2 sensor.

there is a green/red wire in the connector closest to the map sensor but that one signals the instrument cluster based on the haynes manual.

 

If the blue/red goes to pin C in the middle connector, that's the one you want to use.

 

i think i know what the issue is, i looked at the wiring diagrams beavis motorsport posted and the 1996 o2 sensor wire is red/green. Im so confused as to why mine isnt, mine is red/blue, maybe the wiring harness was swapped at one point?
thank you though, its the red/blue wire i think

 

There are a lot of stories of people not having the correct color wire in a certain position in the wiring harness, especially for the O2 sensor (although that may just be a common wire to be looking for). The instructions from FM for wiring up their VooDoo box even say essentially "connect to the xxxxx color wire at position yyyyy, if you have a different color, connect to the position yyyyy anyway, don't go looking for some other wire of color xxxxx". Maybe there are a lot of color blind people out there, or maybe Mazda just used the wrong color sometimes. My guess is mostly wrong color wires.

 

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