# Converting to a heated O2 sensor (1 to 3 wire)



## 79kz400 (Aug 19, 2004)

Bought a sentra 2 weeks ago and after correcting lots of dumb former owner crap i'm driving it to class. Most impressed with the sentra after my last honda which couldn't get out of its own way if you pushed it. And after 6 months of 22mpg i finall got 25mpg after i tuned the crap out of it and put in midgrade. Whoopie.

I'm now way faster, happier, and getting 35-40mpg and maby more when its hot outside but i'm wondering about keeping that gas economy in the winter. I've seen this done on the GM sites especially on the camaro with aftermarket headers. The headers dissipate heat to fast and the stock 1 wire won't warm up enough to close the computers loop so they put in a 3 wire. There were "fog lights" attached to my removed AC system's relay and they've got power when you turn the key so i thought it was a good place to draw my current from. Also very close to the stock o2 sensor location.

My question : Are newer sentras using the same/similar o2 sensor sizes? Thread patterns? My pickup looks the same or slightly larger. How about the altimas? (yes i know they're KA24DE motors) I can get either from the junkyard so it would be a good place to start and see if the sentras computer will accept the heated sensor.


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## Kart Racer (Sep 26, 2005)

I have a Hotshot header on my 93 Sentra, and was having problems getting a signal from my O2 sensor. To solve my problem a friend gave me a self heating O2 sensor off of I think a Ford Taurus of all things. The car works fine now, getting better gas milage than ever.

To wire up the heating element in the O2 sensor I used the wire that goes to the fuel pump. Its located in the relay box bolted to the battery tray.

Hope this helps you out.


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## 79kz400 (Aug 19, 2004)

Good call with the fuel pump relay. i think i'll use the AC relay because its useless now and located in the same relay box. 

What year/engine in that taurus your O2 sensor came from? I knew this was possible but being unsure what sensors fit i thought i'd check first and save myself numerous slightly embarasing parts returns to the junkyard. When you put in the hotshot did you use your stock sensor or get a new one before the Taurus swap?

Maby i'm wrong about all this and most O2 sensors are more or less the same size and thread pitch? I've only removed one once on a junker for fun to see what it would sound like and have never found reason to replace any on the 7 vehicles that i regularly service on our property. If this works i'll be swaping heated O2 sensors into a '92 Grand Prix to. 

Thanks for the RE:!


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## Kart Racer (Sep 26, 2005)

I'm not sure about the specific car that the sensor came from, but it's a Bosch 15717. This sensor is actually a 4 wire, with the only difference being that there is a ground for the heating element and the sensor signal. The 3 wire sensors will use the outer case to ground the signal through the exhaust pipe.

When I put on my header I went about a year with the original sensor, but my gas mileage went bad almost right away. I replaced that sensor with another one just like it before I even knew that a self heating sensor existed. Once I installed the self heating unit my mileage came back right away.

Before I got the one from a Ford for free I went to Auto Zone and looked at a O2 sensor off of a 99 sentra, and it looked the same as the one I used with the exception of how many wires coming out of it.

If possible have your existing sensor with you when you go to get a self heating unit just to make sure that the threads and pitch are the same.


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## 79kz400 (Aug 19, 2004)

Thanks for the part # man. I think I'll rip one from a sentra. I need to drive the car at the time of purchase so i'll take my chances. I might just replace the front one in my truck and use the old one on the car as it seems to be the same. Will post results and maby pix if i think about it.

And i was wondering about that 4th wire... (Duh. Ground!)


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