Secondary O2 Sensor questions
08-31-2017, 12:32 PM
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Secondary O2 Sensor questions
(EDIT- I did digging through some question & answer posts with Katman on the FFSquad site and I figured it could be helpful to update this. He says to splice, and that the black wires shouldn't matter...)
Okay I know this topic has been covered throughout the years online here and elsewhere. However I have yet to get a clear answer on one particular thing. I'll explain my situation, parts, ect. Then straight up ask if I can or can't do what I want to do. I will even post pictures just incase there are still people on here that can actually help. I am quite knowledgable on Honda stuff and do know how to search the web well. Anyways...
I have a 99' LX sedan. I am putting my d16y8 into it. Using OBD2b engine harness and ECU that would go with that engine (from EX). I understand that the secondary O2 sensor is usually in the chassis (floor harness) of an EX model. Meaning I have to run my 2nd O2 directly to the ECU. Being pins A-8, A23, B1, & C18.
My concern is, can I de-pin the wires from the ECU plugs? Then pin the four O2 wires directly into those plugs? Will that defeat a circuit somewhere? Or do I have to splice these four wires into the wires already pinned into the ECU plugs?
Also which black wire goes to which? That is not clarified anywhere either (as far as I have seen)...
NOTE: People have kind of asked this question further into other threads with a similarly related topic, but no one ever gave a clear answer about it (splice OR de-pin options), so because of that I am starting a new thread on a "very covered issue". Trying to be more specific here.
(Also there is reasons I didn't modify a y7 engine harness. Please don't tell me to just add vtec wiring to an old y7 harness, or to learn how search google better, and send me ffsquad links. I have already done that wiring on another car for other reasons, and have searched plenty, and seen the FFS link as well.)
You can see in these pictures I have created my own and already done a clean addition to wrap the 2nd O2 right where it needs to be for my setup. I can now put the engine in and have the four wires ready to be pinned if I am able to do so without problems. If I am required to splice instead (don't want to) I will do so before I try to start the car for the first time.
Please anyone who has done this let me know which way I need to go, as well as which black wire goes to which (I used a black/white wire purposely to make it easier to tell the two appart).
It would be very helpful for me to know exactly what to do here. Hopefully this will cover this more for other people for future reference.
Thanks y'all!
Okay I know this topic has been covered throughout the years online here and elsewhere. However I have yet to get a clear answer on one particular thing. I'll explain my situation, parts, ect. Then straight up ask if I can or can't do what I want to do. I will even post pictures just incase there are still people on here that can actually help. I am quite knowledgable on Honda stuff and do know how to search the web well. Anyways...
I have a 99' LX sedan. I am putting my d16y8 into it. Using OBD2b engine harness and ECU that would go with that engine (from EX). I understand that the secondary O2 sensor is usually in the chassis (floor harness) of an EX model. Meaning I have to run my 2nd O2 directly to the ECU. Being pins A-8, A23, B1, & C18.
My concern is, can I de-pin the wires from the ECU plugs? Then pin the four O2 wires directly into those plugs? Will that defeat a circuit somewhere? Or do I have to splice these four wires into the wires already pinned into the ECU plugs?
Also which black wire goes to which? That is not clarified anywhere either (as far as I have seen)...
NOTE: People have kind of asked this question further into other threads with a similarly related topic, but no one ever gave a clear answer about it (splice OR de-pin options), so because of that I am starting a new thread on a "very covered issue". Trying to be more specific here.
(Also there is reasons I didn't modify a y7 engine harness. Please don't tell me to just add vtec wiring to an old y7 harness, or to learn how search google better, and send me ffsquad links. I have already done that wiring on another car for other reasons, and have searched plenty, and seen the FFS link as well.)
You can see in these pictures I have created my own and already done a clean addition to wrap the 2nd O2 right where it needs to be for my setup. I can now put the engine in and have the four wires ready to be pinned if I am able to do so without problems. If I am required to splice instead (don't want to) I will do so before I try to start the car for the first time.
Please anyone who has done this let me know which way I need to go, as well as which black wire goes to which (I used a black/white wire purposely to make it easier to tell the two appart).
It would be very helpful for me to know exactly what to do here. Hopefully this will cover this more for other people for future reference.
Thanks y'all!
Last edited by DomkeBoy; 03-04-2018 at 08:42 AM. Reason: Found answers
08-31-2017, 01:49 PM
#2
Re: Secondary O2 Sensor questions
This is an educated guess on the black wires.
I believe both are grounds. One is ground for the heating unit of the O2 sensor, and the other is the ground for the O2 sensor.
I suspect the two black wires are crimped together somewhere in the chassis harness and end up connecting to the same ground.
Unfortunately, I only have the 93 civic ETM so I am not able to verify my suspicions for the 99 or 6th gen civics. However, I can see if my suspicions are accurate for the 5th gen as I believe the same methods tended to be re-used through the generations. i.e. the 2007 Si (k series) o2 has those same 4 wire colors. And I found the same colors for the 2006 R18 o2 sensor plugs.
I'll have to check my new Denso o2 sensor for the 5th gen on my parts shelf to see if it has the same wire colors. I think it might.
To bad you don't have the ETM for the car to see the wire paths. The ETM shows every crimp connection Honda did that tends to be buried in the loom somewhere.
I believe both are grounds. One is ground for the heating unit of the O2 sensor, and the other is the ground for the O2 sensor.
I suspect the two black wires are crimped together somewhere in the chassis harness and end up connecting to the same ground.
Unfortunately, I only have the 93 civic ETM so I am not able to verify my suspicions for the 99 or 6th gen civics. However, I can see if my suspicions are accurate for the 5th gen as I believe the same methods tended to be re-used through the generations. i.e. the 2007 Si (k series) o2 has those same 4 wire colors. And I found the same colors for the 2006 R18 o2 sensor plugs.
I'll have to check my new Denso o2 sensor for the 5th gen on my parts shelf to see if it has the same wire colors. I think it might.
To bad you don't have the ETM for the car to see the wire paths. The ETM shows every crimp connection Honda did that tends to be buried in the loom somewhere.
08-31-2017, 03:35 PM
#3
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Re: Secondary O2 Sensor questions
This is an educated guess on the black wires.
I believe both are grounds. One is ground for the heating unit of the O2 sensor, and the other is the ground for the O2 sensor.
I suspect the two black wires are crimped together somewhere in the chassis harness and end up connecting to the same ground.
Unfortunately, I only have the 93 civic ETM so I am not able to verify my suspicions for the 99 or 6th gen civics. However, I can see if my suspicions are accurate for the 5th gen as I believe the same methods tended to be re-used through the generations. i.e. the 2007 Si (k series) o2 has those same 4 wire colors. And I found the same colors for the 2006 R18 o2 sensor plugs.
I'll have to check my new Denso o2 sensor for the 5th gen on my parts shelf to see if it has the same wire colors. I think it might.
To bad you don't have the ETM for the car to see the wire paths. The ETM shows every crimp connection Honda did that tends to be buried in the loom somewhere.
I believe both are grounds. One is ground for the heating unit of the O2 sensor, and the other is the ground for the O2 sensor.
I suspect the two black wires are crimped together somewhere in the chassis harness and end up connecting to the same ground.
Unfortunately, I only have the 93 civic ETM so I am not able to verify my suspicions for the 99 or 6th gen civics. However, I can see if my suspicions are accurate for the 5th gen as I believe the same methods tended to be re-used through the generations. i.e. the 2007 Si (k series) o2 has those same 4 wire colors. And I found the same colors for the 2006 R18 o2 sensor plugs.
I'll have to check my new Denso o2 sensor for the 5th gen on my parts shelf to see if it has the same wire colors. I think it might.
To bad you don't have the ETM for the car to see the wire paths. The ETM shows every crimp connection Honda did that tends to be buried in the loom somewhere.
White Wire -A23 – Sensor Heater 02 Signal (SH02S)
Green Wire -C18 – Sensor Ground 2 (SG2)
Black Wire -A8 – Secondary Heater 02 Control (S02HTC)
Black Wire - B1 – Power Source 1 (1GP1)
NOTE: Random, but they also switched the primary o2 plug on the engine harness to male (instead of female like OBD1 & OBD2a), which is interesting and weird. So I had to custom wire an o2 sensor I had to a female plug as well as extend it to get that to work.
In the picture I posted (2nd o2 wiring I've custom made) you will noticed I used a female plug, so I can just plug my old o2 sensor (male) in without cutting and switching. Not that this matters, just a something I noticed that made my wiring process a little more "fun"...
Last edited by DomkeBoy; 08-31-2017 at 03:52 PM.
08-31-2017, 05:03 PM
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Re: Secondary O2 Sensor questions
I am curious. Even though that isn't what I am looking for.
EDIT: I am putting a d16y8 (with EX engine harness) into LX chassis, not just switching the exhaust style. If you read the post right above yours, you will see I don't need what you are talking about...
Last edited by DomkeBoy; 08-31-2017 at 08:11 PM.
08-31-2017, 06:18 PM
#6
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Re: Secondary O2 Sensor questions
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.T RC0.H0.Xcivic+o2+extension.TRS0&_nkw=civic+o2+exte nsion&_sacat=0
pick one
My 98 is an lx, im running ex header, plus one extension for the rear O2.
work fine. No problem..
pick one
My 98 is an lx, im running ex header, plus one extension for the rear O2.
work fine. No problem..
08-31-2017, 07:58 PM
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Re: Secondary O2 Sensor questions
I have already made extensions to fit my setup. I don't need to buy anything, because I have plenty of extra wires and clips.
For one I am not using an LX engine harness or a d16y7 period, as I stated... two, this is about wiring in a secondary o2 sensor that doesn't exist in a ex (y8) engine harness which I am using on a d16y8, as I stated... third I mentioned I made my own extensions earlier...
SO LET'S PLEASE STAY FOCUSED HERE! These things y'all are mentioning and linking me are of no help to me right now. READ WHAT I AM SAYING. If you don't understand, why even respond with useless information? Sorry if that sounds a bit harsh, but clearly I am trying to figure out something completely different here. It is frustrating to say the least.
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08-31-2017, 08:05 PM
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Re: Secondary O2 Sensor questions
Now, back to focusing on the actual purpose of this thread...
Which of the two black wires goes to which of two pinouts B1 & A8 in the ECU plugs?
Can I de-pin all four existing wire already in the ECU plugs, or do I have to splice into them?
Which of the two black wires goes to which of two pinouts B1 & A8 in the ECU plugs?
Can I de-pin all four existing wire already in the ECU plugs, or do I have to splice into them?
08-31-2017, 09:02 PM
#9
Re: Secondary O2 Sensor questions
I see my gross error in my original assumption. The white and green are the sensor wires and the two blacks are the heater wires. The sensor is quite likely direction sensitive much like a diode is. But the blacks on the other hand shouldn't be.
On the 92-95 o2 (OBD1) the black adjacent to the green goes to the ECU (heater control) while the black adjacent to the white goes to the fused power source. That power source is fed by/from the main relay on the 5th gen.
I hope this info from the 93 ETM is helpful for you.
And unfortunately, I do not have any 6th gen ETM's so I cannot trace the harness side wiring to answer if you can depin or have to splice. Sorry
09-01-2017, 12:12 AM
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Re: Secondary O2 Sensor questions
Looking at the ETM it really does not matter which black wire you put to which. I see now looking at the 93 ETM the black wires are the heater of the O2, one goes to a fused power source and the other goes to the ECU control pin. The heater is going to be a simple resistance coil and should not be current direction specific. One way to test this is your ohm reading should be the same regardless which way you do positive and negative on the two black wires. And you can verify again by reading a 12 volt power source through the black leads, you should get the same voltage regardless of which side/direction you run the power source.
I see my gross error in my original assumption. The white and green are the sensor wires and the two blacks are the heater wires. The sensor is quite likely direction sensitive much like a diode is. But the blacks on the other hand shouldn't be.
On the 92-95 o2 (OBD1) the black adjacent to the green goes to the ECU (heater control) while the black adjacent to the white goes to the fused power source. That power source is fed by/from the main relay on the 5th gen.
I hope this info from the 93 ETM is helpful for you.
And unfortunately, I do not have any 6th gen ETM's so I cannot trace the harness side wiring to answer if you can depin or have to splice. Sorry
I see my gross error in my original assumption. The white and green are the sensor wires and the two blacks are the heater wires. The sensor is quite likely direction sensitive much like a diode is. But the blacks on the other hand shouldn't be.
On the 92-95 o2 (OBD1) the black adjacent to the green goes to the ECU (heater control) while the black adjacent to the white goes to the fused power source. That power source is fed by/from the main relay on the 5th gen.
I hope this info from the 93 ETM is helpful for you.
And unfortunately, I do not have any 6th gen ETM's so I cannot trace the harness side wiring to answer if you can depin or have to splice. Sorry
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