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· TT This
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Discussion Starter · #1 · (Edited)
So I'm finally getting around to taking care of my O2 sensors wiring. Right now I only have the one 02 in the downpipe but the car is looking for two O2's. So I was going to just use the one factory O2 wire that reaches to the downpipe and "combine" the signals at the diagnostic port, bridging the O2#1 and the O2#2 signals with a paper clip. Anyone ever attempted this? It's a 95 with one wire O2's.



 

· The Stars At Night
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2,034 Posts
Hmmm....makes sense on why it could work, I've never tried it, but you should do it and report back...that would make the minor change of cleaning up my engine bay a tiny bit...It looks kind of nasty with my soldered/electrical taped up wires right above my compressor.
 

· The Stars At Night
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Ok...so let me just double check how you did this...you put a paper clip in the diagnostics port for the 2 O2 sensors...then you just plugged one of your O2 sensors into your downpipe and connected it to one of your harnesses and left the other harness open? If that's what you did, I'm pretty sure I'm gonna run out and do that tomorrow...
 

· Banned
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2,275 Posts
Im suprised that works...

The primary O2 (bank one cell one) is used for closed loop feedback to adjust STFT and LTFT

The secondary O2 (bank two cell one) is used to ensure the cat is working properly

Bank two is bank one with less amplitude (if you were to look at it with a spectrometer)

so, if your paperclip is luckily some how changing the signal you just found the easiest solution ever!
 

· TT This
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Discussion Starter · #9 ·
btm7687 said:
Ok...so let me just double check how you did this...you put a paper clip in the diagnostics port for the 2 O2 sensors...then you just plugged one of your O2 sensors into your downpipe and connected it to one of your harnesses and left the other harness open? If that's what you did, I'm pretty sure I'm gonna run out and do that tomorrow...
That is exactly what I did...
 

· TT This
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1,045 Posts
Discussion Starter · #10 ·
swearitsstock said:
Im suprised that works...

The primary O2 (bank one cell one) is used for closed loop feedback to adjust STFT and LTFT

The secondary O2 (bank two cell one) is used to ensure the cat is working properly

Bank two is bank one with less amplitude (if you were to look at it with a spectrometer)

so, if your paperclip is luckily some how changing the signal you just found the easiest solution ever!
Both of my O2's were in the stock downpipes/headers. I did not have any post cat. I don't know if how you described is how my car is looking at it? or is that how Toyota wired all the cars and mine is not even "using" the O2#2 port. Like I said somehow it helped/fixed the O2 cels I kept throwing previously.
 

· Lexotic Garage
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1,741 Posts
Splicing O2 sensor heater and signal wires are a common fix in IS300 turbo projects. it ensures that both banks are getting the same signal so there are not any lean/rich variations.

It also allows the car to be simplified and work off of 1 o2 sensor and one possible o2 sim for the post cat sensor.

If you guys have any questions, feel free to hit me up as I have done this o2 crap time and time again for cars that I have boosted.

Except we didnt do it all ghetto with a paperclip :)
I cut the wires at the ECU and jumper the correct ends and tape off and label the unused ends.

You can verify results with an ECU Scanner. I use an Autotap to monitor the sensor voltages to verify things are working correctly. www.autotap.com
 

· 2JZ yes shit
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1,208 Posts
I had a similar solution, but this was to fix the MAP-ECU from slowly leaning itself out.
What I did (and this was because my downpipe only had one bung) was to completely unplug both stock o2s (the two that were in the header), and leave the one at the cat dangling around but not connected. This elimination of stock o2s seems to force the ecu into 100% limp mode, which means that it reads off the map-ecu table 100% of the time.
This allows my cruising and idle a/fs to be perfect and my wot a/f to be at 11.5 and has never moved since I tuned it 2+ months ago.
 

· Lexotic Garage
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I also had success using an O2 sim for the post cat sensor and using the Split Second ESC-1 Open Loop signal conditioner box to limit the ECU relearning and leaning out the maps under boost. kepts me at about 11.8-12.1 under steady 12-14psi.
 

· The Stars At Night
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2,034 Posts
joeyg said:
Why is everyone congratulating him if he doesnt even know if it works?

The title is "an idea I had, will this work?"

Because he tried it and it did work...that is awesome because it really would do away with the need to try to extend the O2 wires during turbo installs. For single bung downpipes now all you have to do is bridge the two O2 ports. You can just use the O2 sensor and harness towards the back of the engine and screw the one in the front. I'm definitely going to go try this. Congrats man, that is a pretty cool little trick you discovered.
 
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