Removing CIS Brain wiring harness

[K Sykes]

I have been running EFI (Tbitz kit upgraded to MS2) for a couple years and have got it so it's running reliably. I am trying to clean up and simplify the engine bay as there are a lot of new wires running around. What I would like to do is pull the CIS harness completely
out of the car so I get rid of the excess wires and potentially sell the brain and the harness. Anyone BTDT? Biggest questions I have, is the harness a single bundle with nothing branching off between the brain connector and the engine compartment? And if so, can you pull it leaving the various connectors intact?

[dschloe]

What year is your car? I'm looking for a brain and harness for an 80 3.0. If my research is correct there is a relay on the harness aswell but its only for the lambda system.

[mreid]

When you pull it, you will need to remove the driver's seat and pull back the carpet. Once you have access, pull the grommet into the car and push the smallest connectors first through the grommet hole working your way up to the largest connector. They will all fit even though it seems like they won't. The bigger challenge is where the harness goes into the front of the car as it is under the gas tank filler hose and difficult to see. Since it seems you have an aftermarket efi, you may have already address this part. Good luck!

[Flat6pac]

An 80 SC lambda harness is connected near the left shock for the engine. The chassis parts run under the passanger seat with the brain connecting there and a relay and switch.
The chassis harness has 2 red and striped wire running to the front fuse board.
There is several wires that attach to the rear control panel fuses and relay. Everything unbolts and removes through a hole above the tunnel access in the back seat.
The electronic box is unobtanium available.
Bruce

[Laneco]

Bruce is correct.

I've removed 3 of these (an 80, an 81, and an 82), all routed as described, all under passenger seat. Everything DOES fit back through the hole.

Look for a large grommet to plug the hole.

angela

[Daviboy]

I have an 82 SC and did not realise she had a brain lol.......

[K Sykes]

Thanks for all the responses. I got the 6 pin harness on the engine side out. The rest seems to go into the main wiring harness and to the 14 pin or somewhere else. Think I need to do an engine drop if I want to get it out intact.

One question, when folks say pull it through, are you talking about from the engine side into the passenger compartment? Pretty sure that's what folks meant, but not sure.

[Walt Fricke]

Well, my experience with this involved installing, not removing, it. I bought an '82 3.0 to replace my car's 2.7. Luckily, the seller included the brain and wiring harness. It was a pretty easy retrofit. I don't recall any of it tying into the "regular" wiring harness. The O2 sensor part is entirely separate. The 14 pin connector needs to be rearrainged a bit for 3.0s to go into 2.7s, but that's easy to do, and if anything from the brain goes through the 14 pin connection, it will be equally easy to remove it from that connector without cutting wires.

I did not hook up the fuel pump cutoff rev limiter - that is one of the wires which goes forward from the brain. Like the +12 power wire, if you don't want to take the time to thread things from up front back to the brain, you can safely cut those (with suitable precautions about not leaving a cut hot wire lying around), and not destroy the value of the brain and its harness for someone who needs it.

While these motors will run fine without the brain (I tend to call it a mini-brain) as far as the frequency valve goes (at least for track use, where you are at WOT or no throttle, and little in between), I found that starting and idling were much improved when I installed the mini-brain stuff.

So you should be able to trace these wires in the engine compartment, disconnect them, and pull the wiring back into the passenger compartment fairly easily, as others have suggested.

[boyt911sc]

Originally Posted by K Sykes

Thanks for all the responses. I got the 6 pin harness on the engine side out. The rest seems to go into the main wiring harness and to the 14 pin or somewhere else. Think I need to do an engine drop if I want to get it out intact.

One question, when folks say pull it through, are you talking about from the engine side into the passenger compartment? Pretty sure that's what folks meant, but not sure.

Sykes,

If you have disconnected the 6-pin connector in the engine bay, then you could start pulling the lambda wire harness from the interior of the cabin by breaking loose the rubber grommet. Watch out for the metal strips holding the wire harness in place.

Tony

[Walt Fricke]

Yes - the connector in the engine bay is a lot smaller than the stuff under the seat, so you have to pull the engine bay stuff in. Wouldn't work the other way.