Rep Power: 0

Just picked up a 2001 Civic LX and am having a strange issue I have never ran into before.
I know very little about the car and am piecing it together as I go along.
Trying to clear all the codes off before I put more money into it.

The check engine light is on, and has all 4 cylinders missing as well as a O2 Code.

The Downstream O2 sensor is plugged in, and I cannot find the Upstream plug on the harness anywhere.

The car was badges as a EX but the VIN and the computer run as a LX

I think the Engine harness as well as the Motor was swapped from a EX into a LX and there is no port for the downstream O2 sensor. (I looked under the car there is no body harness connector)

If I go get a Engine harness from LX (with 2 o2 sensor ports) will it just plug into the computer with no issues?

Thank you for the help, have a wonderful day

I have had this car for 2 days and will fix and wrap and solder everything correctly, I am trying to un-bastardize it now.


Downstream connector plugged in, photo makes it look like the upstream is plugged in.


Downstream sensor and underside of car, needs oil pan gasket. There is no cat under the car and no body harness for a downstream sensor near the shift grommet.

The 1 o2 sensor connector that fits the downstream sensor, was verifying the other plug was not cut and hidden.

This is the only o2/afr sensor plug.

 
Rep Power: 366

seeing it have the LX header, I would instead bet previous owner put an EX badge or rear bumper. I bought a scrapyard bumper from a LX and using in my EX.
also, you car uses O2 sensor (narrow band), don't buy the wideband ones used on 03+ - cheaper, so great!)

Read here for exhaust configuration in the last two posts:

https://www.civicforums.com/forums/2...p-version.html

 
Rep Power: 0

So it looks like my exhaust is the OEM D17A1 LX/DX

But my engine harness is a D17A2 (as well as the engine)

I do not have the downstream O2 connector that would be found under the car at the shift grommet.
(from what I now understand the downstream O2 connector is part of the body harness in the EX)
(So the engine harness has 1 O2 sensor and fits the length and position, and the body harness would have 1 O2 sensor as well)
(being the BODY is a LX and the ENGINE is a EX, I am missing a plug)


**Can I ADD PINS to the ecu connector to "put back" the upstream O2 sensor on this harness?
OR
**Do I need to hit up Pick and Pull to get a replacement "correct position and number" wire harness for a LX/DX

Very good post BTW, I ran through it to confirm a few things but just gave it a full read.
Im trying to go stock as possible.
This is to get me to work and replace my 2001 S10 that gets 10mpg.

Other option
**Replace body harness and exhaust to make it a full EX?





The VIN's don't match if you can believe it.

 
Rep Power: 0

https://www.civicforums.com/forums/1...g-pinouts.html
Well I'll be, let me see about getting a pinning toll and running some wire, the EX harness is different, so I should just be missing the pins.
Hopefully Ill be able to save this harness and not throw it away.

 
Rep Power: 0

Keeping a thread in case anyone else buys a used car like this.
I took a bunch of picture's of the ecu pins and it has wires for the primary and secondary coming out of the ECU

 
Rep Power: 0

So it looks like I will need to run 2 wires from the ECU and fix the connectors as the other harness will not have vtec support.

Gods this is a pain h\in the ***. but I THINK this sounds right

tap onto the power and ground and run a shielded sensor wire and a o2 sensor heater wire back to the computer and pin it?

oh and make sure the o2 sensors plug into the right port.

 
Rep Power: 366

Wow, good job! You only needed some pointers and up and done it
Glad you got it solved!

 
Rep Power: 0

Thank you "1HGEM22504L006420" at my local parts yard, I have the right harness installed.
This LX harness lacks the connector set for the VTEC.
Will the engine run fine without the VTEC plugged in, will I need to get a bypass plate?

My main worry is if it will cause any damage to the engine?
This is to get to work and back, economy driving car project.

This is physically installed on the motor in the car, but my engine harness lacks these connectors at it is a LS Coupe.

I will eventually get a non-VTEC head from the parts yard, and have it machined, valve job, seats, etc to have on stand by when I replace the head gasket.
But that's not in the budget right now.

 
Rep Power: 366

too many going around with the VTEC non-functional (cheap Japanese engines around). No issues.

 
Rep Power: 0

Sorry for the super late replay, life got busy.

Swapped in the Harness, its still not seeing the secondary o2 sensor AND now we have a flashing D Light and erratic shifting.

I am guessing there is also an EX computer in the car as some of the dash was not put pack together well.

With the Engine+Transmission being an EX (and now I assume the computer is as well) would the ECM not accept the LX harness pin-out?

Would the transmission wiring be different? I cannot imagine so, I will need to thoroughly go though the AT side for breaks or shorts.

Do you think it would be better to try :

1. Add the missing 02 sensor to the body harness, keeping the Vtec function. (I have never added pins to a factory harness)

2. Troubleshoot the junk hard harness issue for the broken shift solenoid wire, and hope the EX ECU is compatible with the LX harness.


Still having a issue with the ignition timing "walking around" but I have made another post about that.
https://www.civicforums.com/forums/3...ing-issue.html