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Discussion Starter · #1 ·
I took off my stock header and flex pipe and put on an OBX header. We only unhooked the center one the top and bottom we just removed and sat them to the side.

When we went to put them back on we forgot which was the top and bottom 02 sensor.

I have the gray and blue one left over. Im pretty sure the blue went into the cat (center) but the top i think was gray, and the bottom one was black?

Can anyone confirm the correct order?

I think Tom turned off the second and third o2 sensors in the tune but if i have the bottom one hooked up and its turned off in the tune how will it run? Lean? rich?

Will i get a code if i have them in wrong?
 

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A quick look at autozone's website will reveal that the primary O2 sensor (before cat) is gray.

Also the ECM only needs the primary O2 sensor to know whether the engine is running lean or not, the other one (or two on certain year models) is/are just for emissions control.
 

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Discussion Starter · #3 ·
A quick look at autozone's website will reveal that the primary O2 sensor (before cat) is gray.

Also the ECM only needs the primary O2 sensor to know whether the engine is running lean or not, the other one (or two on certain year models) is/are just for emissions control.
So are the colors gray, blue and black? How do you look this up?
 

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BodyKits=PantiesDrop
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The only one you need is gray. You want to put this one in the collector at the end of your header so its sniffing all cylinders, not just one.
 

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Discussion Starter · #6 ·
Yeah, its definitely the gray one that needs to be installed.
And we put the black one back in? i think i have the blue one and the gray one left over. If we didnt put the wrong one back in then i think we put in the wrong sensor.

I think my brother actualy got the order wrong we we took em out the other day. He seems to think the black on went on top so i think he got the order wrong then and that why we thought the black one went on top.
 
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