I am ready to route wiring from the engine bay to the cockpit for my AFR meter. I am curious about where folks have routed wires / drilled holes, etc. I know I want to stay away from ignition components based on experience, and it looks like the current wire harness access point is pretty much stuffed. The connector is for an Innovate MTX-L and the connector to feed through to the cockpit is probably 1/2 an inch long, so it is more than fishing a couple wires.....

Appreciate any experience based advice. The exhaust bung is welded in place so this is next on the agenda so I can start working on tuning the D-Jet setup.

Kind regards,

I used a coat hanger wire to thread more wires through the "snorkel" and alongside the main wiring harness.

--DD

I ran mine thru the tunnel. Dual CHT, Innovate AFR, fuel pump power, oil pressure and oil temp

Did you just drill a hole next to the shift rod in the firewall?

That would be ideal. Not sure if I could make that work with the connector on the Innovate. I would have to push all the pins and reinstall on the other side without damaging anything. If it was a single or couple heavier gauge wires maybe. Good suggestion though!!!

I'll try for take a pic tomorrow. I didn't have to drill any holes

I drilled a hole next to the release for the engine lid. same as your situation the connector for my AFR was too big to thread through existing wiring harness. then ran the wires behind the backpad and down the top of the tunnel under the rug.

Click to view attachment

I have the dual CHT, AFR, and oil temp/pressure wires go thru the speedo cable hole. The red wire poking thru the boot was done by the PO and is for the fuel pump.

I heard somewhere that part of the "firewall" was double layer sheetmetal and part was single. Something about the difference of above vs below the engine tin.

Ideally for shortest route of wiring would be to go directly into or beside the tunnel I suppose. I was thinking of routing it there in order to get away with not having to run an extension cable for the gauge..... but that is an option.... I believe I have the 8 foot cable now.... which got me there with my 912.

Yes, the firewall is double layer (with an inch or so air gap) on the lower part. You can see where the seam is if you take the back pad off. It basically aligns up to where rubber engine seals up front.

On my car there were holes on the upper part of the firewall in the center. I believe that is used to mount the engine bay sound pad. I ran my CHT wire through that hole, down behind the backpad, and up through the tunnel. My AFR I basically did what Dave described.

There's a couple of places to drill/cut a hole big enough for the connector.
To close the big hole you can take a sheet metal patch, drill a hole just big enough for a wire grommet, split the patch, insert your wire and grommet, then RTV/seam seal the patch (two halves) to the bigger hole.

I had to get the longer cable from Innovate as the 8' that came with it was about 10" too short

Yep, I can see right now I am going to save myself some pain and suffering by getting the 18' cable now rather than struggling with routing the 8' one I have.

Based on some issues in the past with ignition noise possibly causing the gauge to glitch I am going to route my cable outside of the normal harness and ignition area, just to keep the signal as clean as possible. I appreciate all the helpful advice guys. I now have a plan to make it happen.

I installed an Innovate O2 sensor and ran the cable through the same hole as the rest of the wiring harness under the engine shelf.

I pulled the bottom of the snorkel loose and then made a spacer out of a piece of a 2" smooth PVC union. The rounded edge of the end of the union just fit around the factory opening in the firewall and the sharp, cut edge fit the snorkel well.

I cut a slice of it about 1/2" thick to make an "O", and then cut about a 3/4" section out of the side to create a "C"-shaped piece. I painted it black and after I fished the cable and other harness through the hole behind the snorkel, I slipped the "C"-shaped spacer behind the snorkel and let the added cables run in through the opening in the "C". I then applied a little silicone to make it weather-proof.

Click to view attachment Click to view attachment

I think I like what you did here. I am looking to clearly understand what type union you used. Here are the google results for "2" smooth PVC union" on Amazon. Is any of this what you are talking about (I did a Google search and got like 10,000 hits, yikes)

https://www.amazon.com/s/ref=nb_sb_noss?url...mooth+PVC+Union