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HOW-TO: build your own O2 cheater

128K views 125 replies 49 participants last post by  ah1f39 
#1 · (Edited)
Here are the instructions for making your own O2 sensor from $2 worth of parts from radioshack instead of buying a 35 dollar one from CFM or a 9 dollar one from ebay...



Needed:

**NOTE: if the O2 sensor is really rusted on, I recommend PB blaster for helping get it out**
1. O2 sensor removal tool ($13 from local hardware store...maybe not needed but made things easier)
2. Open-ended wrench the size of the removal tool (mine said 7/8" but was actually 1")
3. Ratchet for the removal tool if needed
**NOTE: the transmission will get in the way if u us the ratchet to loosen the O2 sensor too far so use open-ended for as much as possible**

4. Soldering pencil
5. Solder
6. Wire cutters
7. Wire strippers
8. exacto knife

9. A 1 microfarad capacitor ($1 from radio shack)
10. 5 pack of 1 megaohm, 1/2 or 1/4 watt resistors ($1 from radio shack)
11. electrical tape
12. some sort of protective covering for the finished product...be creative, finished product will be somewhat close to the transmission


Process:

**IN ORDER TO REACH THE SENSOR LOCATION ON MY HEADER, I HAD TO ADD A COUPLE INCHES TO ALL FOUR WIRES**
...this is not included in the how-to but you may be required to also do so if the sensor needs to be back near the flex pipe like mine did

1. Unplug the blue O2 sensor connector


2. Use the O2 sensor removal tool and an open ended wrench to remove the O2 sensor...a ratchet might be helpful to get it started but will get stuck between the sensor and the transmission if you take it out too far...
**NOTE: i found it to be easiest to remove the sensor right after parking the car, while it is still quite warm...careful not to burn yourself but i think its easier to get it started


3. Use the exacto knife and wire cutters to CAREFULLY cut the rubber sleeve without cutting the wires about 2 inches from the connector end...this will keep the cheater away from all the exhaust heat


4. Pull the longer end of the sleeve down so that it squishes down on the sensor and use some electrical tape or something to hold it down as far as possible while you work.


5. Between the two parts of the sleeve, separate the two white wires from the gray and black ones...the white wires will not be touched.


6. Cut the black wire in the middle of the area available (one cut) and cut a small section (half-inch) out of the gray wire (two cuts). **I actually did this 2 cut step later but recommend it here instead**

7. Strip each of the available wires about 1/4 inch or so down...just enough to solder. Then twist the strands to keep them together.


8. Take the capacitor and wrap the black wire (connector side) around one of the wires coming out of the capacitor, make this connection fairly close to the capacitor.

9. Fold back the other wire coming out of the capacitor and twist on the gray wire (connector side)


10. Wrap the remaining black wire (sensor side) around the black wire from the connector side and its capacitor wire.


11. Solder the black wires and one side of the capacitor together, trim off any extra wire from the capacitor, and wrap in electrical tape.

12. Take one of the resistors and wrap one of its wires around the gray wire (connector side) and second capacitor wire

**NOTE: it has been recommended that you use heatshrink tubing instead of/in addition to the electrical tape...so you may want to put heatshrink over the capacitor and wires here**



13. Wrap the other end of the resistor around the other gray wire (sensor side)

14. Solder both of these connections and wrap in more electrical tape **AND/OR HEATSHRINK**
.



15. Remove the electrical tape holding down the sleeve and cut a small slit in the side, allowing the sleeve to partially cover the cheater electronics.


16. Tape the sleeve down over the electronics.

17. Use whatever protective cover you have to cover it all up.


18. More electrical tape to keep out moisture and dirt.


19. Finger tighten O2 sensor back into the car.


20. Use the removal tool and open ended wrench to tighten the O2 sensor. Torque it down a bit but don't crossthread/strip it.


21. Plug blue connector back in and enjoy your lack of engine light.


**I am not responsible for the use of this mod to break the law/pass emissions tests illegally. Any equipment which removes emissions equipment is for off-road use only**
 
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#7 ·
if u mean performanc-wise no, i did not...the purpose of this mod was to get rid of the CEL once i put my new 4-1 header on...i dont have the header on right now...so the mod actually accomplished nothing for me as of yet because im still on the stock header/cat setup...but i know ill be glad its already ready when i do get the header on...and im confident everything worked properly because of the fact that i DIDNT notice a change...thats a good way to tell everything went as planned

Theres always the good old fashion extensions that move the sensor out of the path of exhaust flow that work also. I just saw those on sale yesterday at the local speed shop.
just be careful of the transmission...the sensor is aimed right for that thing and it was a pain removing it because it was aimed right for the transmission...i dont know how long those extenders are but just a heads up
 
#5 ·
Theres always the good old fashion extensions that move the sensor out of the path of exhaust flow that work also. I just saw those on sale yesterday at the local speed shop.
 
#10 ·
just be careful of the transmission...the sensor is aimed right for that thing and it was a pain removing it because it was aimed right for the transmission...i dont know how long those extenders are but just a heads up
It only sticks out about a inch further and it shouldn't be towards your tranny or somethings wrong with you new header.
 
#12 ·
#15 ·
also, illinipo, you may notice i changed the plans a little to make it cheaper and simpler and still just as effective...i also skipped the explaining part that not many people care about and provided more pictures...but that is a good how-to and does give a good description of it...and i actually used the diagram from that howto to make mine, haha...yes, i realise im not the first one, i just noticed nobody had put anything on this forum yet, so i did

also: bump for all the pics being there now...or at least should be if my internet works
 
#20 ·
You should probably get some heatshrink tubing that will fit over the capacitor and take the electrical tape off...in my experience electrical tape doesn't hold up very long when its exposed to heat changes and the elements. I've had to rewire both of my headlights after making that mistake...
 
#25 ·
hey orangeSVTguy we need a favor!!!

so did you throw the header on and try it yet???????? i'm anxious to find out if this really holds up to it's intended task
 
#28 ·
i did get the header...went to install it and couldnt get the stupid stock crap off...everything was rusted solid...none of the local shops will touch it cause it removes the cat converter...so i plan to go up to my cousin's garage on wednesday and get this mofo in...sorry guys
 
#37 ·
PM S2. He will put it in his "How-To Archive", which is already stickied in just about every forum here.
 
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