inline4

In short:

If you are using a non-VX engine harness in your swap

-Your signal wire is not reaching the ECU

-The VX shock tower harness has an extra plug which the signal wire to the ECU is in

-This same extra plug is unused with a NON-VX engine harness but it has the wire (orange with blue stripe) which runs to pin location D14 (o2 sensor signal), therefore we need to depin this and pin it where it can be of use.

-Find the signal wire from the o2 sensor(usually white, then after o2 sensor plug it turns wht/red stripe), trace it back to the shock tower plugs (using a multimeter is easier), it should be on one of the big ones

-Wire color for me was white with red stripe, depin it and plug it into the correct slot (orange with blue stripe) on the VX plug that was unused in the swap, OR

-You can also depin the orange with blue stripe wire from the unused VX plug(shock tower side) and pin it into the back end of the white with red stripe plug, it looks cleaner this way.

EDIT, Pictures and simpler: Just do the o2 sensor part in this write-up: https://honda-tech.com/zerothread?id=644434


THE LONG VERSION

A multimeter will do wonders cause you will have a shorter time tracing the wires if you use the connectivity setting.


This is for my 1992 Honda Civic VX with b20b swap, p75 ECU, p75 engine harness, and 4 Wire o2 sensor which all obd1+ b-swaps should be using

I'm not sure if this applies to CX owners with swaps but it may.
I've been trying and trying to get rid of this code 1 ever since my swap.
If you used the original VX or CX wiring harness and added extra wiring this may not concern you, but if you used an integra wiring harness or other harness and thought the o2 sensor wiring would be a direct plug in deal... it's NOT. That's what I believed to be true because I saw it posted everywhere. I would always get that darn code 1 and no one would know why, no one would post info how to get rid of it.

I went through 2 o2 sensors, changed all the gaskets on the head, gaskets for the header, exhuast, etc. and it was still there.

so my solution was to go to the source.. the wiring.

i traced the o2 sensor wiring to the shock tower harness then to the ECU.

o2 sensor wiring is suppose to be

black -goes to pin A6
black -goes to pin A25
white (signal) -goes to pin D14
blue or green -goes to pin D22

Mine were going to

black - A6
black - A25
white (signal) - Nowhere
blue (sensor ground) - D22

ok, tracing these to the o2 sensor harness i got both blacks and the sensor ground going to the right locations on the ECU, however the o2 sensor signal wire wasn't, it stops at the engine harness.

You will need to trace the o2 sensor signal to the shock tower plug. Now remove the pin from the engine harness side of the shock tower plug. Mine was white with a red stripe for my signal wire. Now find the extra plug on the shock tower harness that you didn't need to use for the swap (this only applies to VX's, i don't think CX's have the extra plug). Just plug the pin straight into the slot that orange with a blue stripe goes through. You can put tape over it to keep the moisture out too. OR you can depin the org/blu wire from the unused VX plug (shock tower side), and pin it to the back of the plug (shock tower side) that the o2 signal wire (wht/red) runs to, it looks cleaner this way.

That part is all done.. I now get signal, when before I didn't

Now your all set.

I get no more code 1 and my gas mileage has improved a ton. This might be your problem if you used an unoriginal harness and have a swap and cant get rid of that pesky code.

Im not sure if this information pertains to CX owners, but if you're geting that code too then its worth a try to source the wires from the o2 sensor to the ECU.

Heres the pinouts courtesy of the ECU pinout thread and FF-squad


the pinout thread
https://honda-tech.com/zerothread?id=1171263


Good luck, get rid of that code! muuahaha

In conclusion, not ALL 92-95 civics are prewire for 4 wire o2 sensors for the factory, this is only 3/4 true.


Modified by inline4 at 8:02 AM 7/26/2006

fmrprojects

yeah i did a swap for my cousin and we had the same problem. i just had a shop do it its cheap save urself the headache. u have to pin and repin some pins

JDM_Ej

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fmrprojects &raquo;</TD></TR><TR><TD CLASS="quote">yeah i did a swap for my cousin and we had the same problem. i just had a shop do it its cheap save urself the headache. u have to pin and repin some pins</TD></TR></TABLE>

Bah, thats giving up!

fmrprojects

nah that isnt. i do a lot of wiring but on that it was too much pinning and re pinning. cant complain when u pay $10 to get it done how long is it taking this guy to do it

inline4

edited, i did the write up wrong.. found out you only have to mess with one pin, and thats only on the shock tower harness section.


Modified by inline4 at 4:41 AM 2/3/2006

nsxmatt

I just ran 4 new wires to the ECU on my VX. Worked fine, took 20 minutes. I had heard there was the wiring already there but why spend that much time fooling with it.