How to replace your 02 sensor with a LC1/LC2 or other wideband with narrowband emulation

This is how you can use an LC1 to emulate your stock NB sensor. The diagram is for a 4 wire system.
With the 4 wire you will be using the power source that powered the old NB sensor.
The gauge kit can be purchased here.

Here are the basic LC1 instructions

This is the stock setup. Don't mind the erased part that was for a different diagram and I never got around to updating the image.
The complete diagram can be found here though.

Now with the LC1 wired in

If you don't use a resistor going from power to HT you will get a CEL. I have been working my way up to find the highest resistance smallest resistor possible. Bigger resistors use more power and create more heat. 50 OHM is the highest I have gotten but it may be possible to go higher. I will update when I play with this more.
If you use a 50 ohm make sure it is rated for 5 or more watts. This resistor still gets pretty hot to the touch but it's acceptable. If you plan on trying higher resistance use this formula to calculate the wattage resistor you should use. *
voltage*voltage/ohms. For a 50 ohm resistor on a 12v electrical system with a little buffer that is 14*14/50 = 3.92. Always round up to at least the next size larger.
Thanks to rmeller and a few other electrical gurus for teaching me how not to blow up my car with resistors
Once it's wired check to see how hot the resistor is getting and make sure it's not close to anything that could be sensitive to that heat. Also realize it will get a bit hotter when the car is running and the alt is charging.

Make sure you ground the LC1 to the same ground as the rest of the vital electronics.
It is highly recommended you ground the gauge at the same source.

For a single wire you will need to find a power source. You can probably use the same circuit but it won't be staring you in the face. You also don't have to deal with putting the resistor in line from the power wire to the ECU ht pin since there isn't one.

courtesy of