S!K TEG

start from day 1....

July 2012: I bought my 1998 Honda Civic HX


It passed emission with flying colors, no Check Engine Lights.

December 2012: The Stock D16Y5 engine threw a rod through the block.

January 28, 2013: I replaced the Motor with a full D16Y8 out of a 1998 Civic EX


I used everything off the y8 included the ecu. ( no engine harness due to previous owner using it for his b16 swap.)

February 2013: My Check Engine light is on for code 41 ( primary o2 sensor.)

I realized the HX has a 5 wire o2 sensor.


so I had to convert my 5 wire plug to a 4 wire plug using write-up which came out to a major fail.
After all the headache, I just decided to get a dx harness.

February 2013: I bought a 1998 Honda Civic DX engine harness that was running a b20.

Why?

because it has the secondary o2 sensor on the engine harness as opposed to the EX that has the secondary o2 on the cabin harness. If that makes sense.

All I did was wired in the my usual, knock sensor, vtec, vtec switch etc

March 2013: After having the car down for a minute, I got it running but now was throwing in a secondary o2 sensor code 65.
I replace the o2 sensor with a new OEM one, had the code reset, and still popped up. So, I assumed it has the header cat that went bad.



I didn't want to spend $300+ for a new one. So I just bought an after market header.


I also did a chipped OBD1 p28 with a y8 base map since I still had emissions.

July 1, 2014: I forgot about my OBD1 ecu untill I took it to emissions to find out that the computer doesn't read.

July 2, 2014

I plugged in my p2p ( obd2a d16y8 ecu) and threw the C.E.L for code 65 ( secondary).

So I went and had a new catalytic converter welded on to the exhaust system.


so now I have this system of exhaust system




July 6, 2014:
My code has not gone away even after replacing the o2 sensor AGAIN.

so I looked up the diagram to wire my secondary o2 sensor directly.

(I high ligthed the important ones for easier reading)


which are the same color as the same harness that was gratefully donated to me by a friend.


July 7, 2014:

I went on to http://www.ff-squad.com/technet/wiring.obd2a.htm for extra diagrams and used this

(edited for easier reading)


so I had them wired up the necessary spots.

I was left with one wire (blk/ylw)



which I wired into my fuse #15 under my dash ( where it belongs if you look at the highlighted diagram)

but didn't help get rid of the code.

and that is where i left the car.

--------------------------------------------------------------------------

cliff notes:

Secondary code doesn't go away!!
EX have secondary o2 wiring on the cabin harness
HX/DX/LX have the secondary o2 wiring on the engine harness
but
HX/DX/LX/EX have the same secondary o2 pin-out at the ecu as proven by ff-squad

ignore my previous post about the p2n ( hx ecu)
--------------------------------------------------------------------------

so only thing left to solve is.....

why is my secondary code ( 65 ) coming on with my p2p?

grumblemarc

iTrader: (4)

Wait. This is confusing as hell. HX shell. DX harness. Y8 engine? Exhaust leak?

S!K TEG

Yes and I replaced my header with a 1 piece header and a new 1 piece 2 1/4 exhaust system when I got a new catalytic converter replaced.

Former User

Why did you install a DX wire harness for an EX swap?

tony_2018

Where are both your o2 sensors located?

OptimisticWay

This looks like a communication issue because you can clear one code with one ECU and the other code with the 2nd ECU. if both of these ECU's are capable of throwing 41 and a 65 code then it is highly probable that it is a communication issue with the wiring feed to the ECU.

Do you know off hand if these two ECU's have 41 and 65 codes?

OptimisticWay

•P2N : 96+ OBD-2 Civic HX Coupe
•P2P : 96+ OBD-2 Civic EX Coupe

What OBD1 ECU are you wanting to run? A P28? This was not in the info. Have you ran this ECU with any results? Are you using a jumper harness?

ECU Identification
http://www.hondata.com/techecuid.html

S!K TEG

1. Because my hx has a 5 wire primary o2 sensor instead of the normal 4 wire.

2. Ex have the secondary plug on the cabin harness instead of the engine harness. So I eliminated that hassle of wiring in the secondary o2 by having it on the harness already.

S!K TEG

Primary is up front on the header and secondary down bottom behind the cat.

Former User

You apparently eliminated one hassle to gain a bigger hassle, which the EX harness may have circumvented.

S!K TEG

Yes both have a code for both programmed.

No, p2p only throws code 65 and p2n only for code 41.

Didnt know what you meant.

Former User

At this point, words will not suffice. Some clear pictures of the wire harness(es), the O2 sensors and the wire colors in the connectors, and your wire splices are absolutely required.

S!K TEG

Agreed. I'll post pictures later and a better understandment.

OptimisticWay

That answered my question. What is this Chipped ODB1 ECU that you speak of?

S!K TEG

P28 chipped with a y8 map, No c.e.l.

OptimisticWay

When you run the P28 ECU, you do not get any check engine light?

andoxviii

iTrader: (1)

OBD1 only looks for 1 oxygen sensor. Pre-cat

grumblemarc

iTrader: (4)

The P28 is not a factor in this as O2 sensors can be turned "off" in the map and the OP cannot use it for smog.

tony_2018

In order for him to pass emissions everything needs to function. Then after he pass emissions he can plug whatever the **** he wants. Atm his o2 sensors are wired weird and that needs to be straighten out.

S!K TEG

I am home now and will update my first post with pictures, diagrams and better detailed explanation. Bare with me, I am frustrated and ready to take my car out to the doons for some target shooting.

tony_2018

Is the cat located up front like the DX/LX/CX models or is it setup like the ex model. If you extended the o2 to the back you better check those wires and make sure the actual secondary o2 wire is shielded.

S!K TEG

EX exhaust set-up now and wires are good to go.


I also updated my first post to help understand the process.

tony_2018

You better make sure that the secondary o2 sensor wires are correct and that the main sensor wire is shielded.

S!K TEG

I have unplugged and re-plugged everything, so I'm sure everything is wired up correct. As far as shielded, what do you mean?

HondaPartsHero

Compare vs this
http://ff-squad.com/wp/?p=395

And if all your wiring is correct