After scoring a deal on a Innovative LC-2 wideband O2 kit for 20% off on Amazon a few weeks ago, I hopped on the forums hoping to find a tutorial for installing a wideband O2 sensor in our cars. Unfortunately, there doesn't seem to be any good tutorials for this - something that seems crazy to me. Of the few threads that do show up for wideband installs, many of them have very little information in them or no posts responding to the OP.

Despite the lack of information, I've been able to piece together a few things from the forums on the installation process:

1. It is possible to use the open ACC port in the fuse box as a key-on source for the wideband.
2. No one is running a relay from the battery with the key on power source controlling the relay. People are running the wideband off the key on power source apparently with no issues. Very little mention of current draw issues here which is good.
3. No one has mentioned a good place to mount the wideband controller. I assume there is probably somewhere good to mount it under the passenger kick panel by the ECM. I'm mildly worried about a leaky heater core ruining the controller if it were to leak though.

Ideally, I'd like to follow the instructions that come with the LC-2 and run a switched relay from the battery. The only issue is that even though I have an electronics background (I'm a computer engineer), I have no experience with car electronics. It is simple enough to find an automotive relay on Amazon, but finding all of the various connectors to cleanly connect to a relay, the battery terminals, inline fuse holders, fuse adders, etc becomes a bit overwhelming. Especially when I don't know if it is best to shop for all of this stuff locally or buy it online.

I still haven't decided where I would mount the relay at if I do go down that route. Most of the relays I've looked at are not sealed, so it seems like I would need it inside of the cabin by the ECM and the wideband controller. With how limited space is down there I'm not sure how much of a possibility that is.

 

No disrespect but You're being a typical engineer. These are fabricated issues that will very easily be resolved once you start the job.

You also seem to have a great grasp of what does need to be done so it should be a breeze. I'd be more interested in figuring out how to datalog it if I were you. Edit: NEVERMIND EBL should be easy.

 

The more I look the easier it sounds. It looks like I need a relay, a pre-made relay connector, an add a fuse to pull power off the ACC fuse, a 1A fuse, and a inline fuse holder for the connection to the battery. Mounting the parts is definitely a fabricated issue. I'm sure I can find a place to put them easily enough once I get into it.

The two remaining things I need to figure out are 1. What is the best way to hook onto the + and - wires of the battery for the relay. I'm thinking of finding some sort of circular connector that I can solder onto a wire that I can tighten the battery cable nuts down onto. 2. It looks like the Innovative LC-2 is using 18 gauge wires. Do I want to go with 18 gauge wires all around or step up to something like 14 gauge wires just to be safe.

 

Resurrecting this thread from the dead as I finally get around to working on this project. I pulled the passenger side of the dash apart hoping to find a hole or two that I could use to run the LC-2 wire and the battery wires through. Unless I'm missing something, I don't see anything large enough to put the LC-2 wire through, as it has a fairly large connector on it.

Others that have installed a wideband O2 sensor, where did you route the wideband cable into the cabin?

 

There really aren't "spare" holes in the firewall except the drivers side. If you don't have cruise control on your 91, there is a plug in the firewall for the cruise harness. You can get through there, otherwise you're going to have to look at the PS and look to see where you can drill a hole without hitting something on either side

 

On the passenger's side, there are about three holes total. By the frame rail, there's a large hole for the HVAC wiring harness, the only other two are for the heater core. The rest of the holes on that side are under the fender/behind the kick panel. That's where the ECM harness comes inside, the antenna wiring, and the door wiring where applicable. There's probably room there to put a new hole for your wires. Drill hole, install a rubber plug and punch a hole for the wiring, or use a tightly fitted grommet.

 

It does have cruise control. I was hoping to avoid drilling any new holes...I know there is room to get the power and ground wire from the battery through the antenna port in the kick panel. Maybe I can sneak the LC-2 wire through a port on the drivers side and route it that way. If not, I'll just have to drill a hole I guess.

On the drivers side is the steering column grommet pretty much the only place I could come through?

 

I hadn't considered the antenna hole. If you're not using the radio, that is a great place to run stuff. On my last car I used that to run the amp power wire through

 

I will definitely run my two 14 gauge wires for power/ground through the antenna hole since it is the cleanest way to reach the battery. This weekend I'll go out and see if I can find anything on the passenger or driver side that I can force the LC-2 wire through. I'm honestly surprised there isn't a walkthrough thread for installing a wideband O2 sensor on these cars with best known locations to run the wires. I'll have to keep a walkthrough in mind as I do mine.

The connector on the bottom right of this image is what I need to get through the firewall.

 

I worked on the car today for about four hours, but got distracted by another wiring issue. While looking for holes in the firewall, I noticed that the cruise control grommet was pushed out and the mysterious red wire that runs across my engine bay was going through it. I followed that wire into the center console. removed the radio plate for the first time in about 5 years, and was reminded of all of the cut off wires with electrical tape wrapped around them shoved in there. After taking most of the passenger side interior apart, I was finally able to confirm that none of those wires in the center console were attached to anything on the other side either. In total, I removed about 18 wires that at some point were connected to an alarm system and some sort of audio equipment in the trunk. Why any of this stuff was ever installed, then removed in what amounted to cutting the wires at each end and half-assing the electrical tape job is a mystery only the previous owners know the answer to.

With the cruise control grommet properly installed now, I think I may be able to run the LC-2 wire through the grommet. Hopefully next weekend I will actually be able to get this thing wired up.

 

Went out today and routed the LC-2 wire through the firewall. After about an hour of trying to force it through the cruise control grommet on the drivers side, I decided to cut the grommet on the top part so I could run the LC-2 wire through. Once I get the whole thing setup I'll put a little bit of silicone on the grommet to ensure a tight seal.

Routing the wire wasn't too bad. I zip tied it to the fuel lines and then ran it across the transmission cross member over to where I am going to belt the bung into the exhaust. This should hold the wire tightly up against the body as it passes up the engine bay past my headers. I don't think the fuel lines should get hot enough that I would have to worry about the wires melting, correct?

 

For anyone that stumbles onto this post in the future, I did get this project finished. I wrote up a guide on my install here: https://www.thirdgen.org/forums/elec...-wideband.html