Can anyone give me any advice on how to get these wires through this clip? I'm really struggling to get them through. Also, please correct me if I'm wrong, but these wires up under the dash that ran to the computer are the same wires that run into the passenger side fender well from the engine bay right? I'm doing a 350 swap with a non computer controlled carb and no A/C, so I have no need for any HVAC or computer/engine sensor wiring. None of these wires should affect starting, ignition, lighting, or gauges, correct?

Thank you so much!

 

Can't get em "through that clip". Doesn't work like that.

So, go visit a vehicle assy plant some time. Not important what vehicles; although, the Bowling Green KY plant where they build Corvettes, is a good choice. The Georgetown KY plant where they build the Camry is another good one. It's not SO critical what cars they're building (although IMO, I'd rather watch Vettes being built, than Camrys, butt, the lessons are identical), the point is, HOW CARS ARE BUILT.

Let me assure you, there are NOT 10,000 yr old gnomes laying up under the dash of finished cars, with tools forged in the fiery furnaces of Hell from virgin nonobtanium alloyed with traces of galactic irreplacium found on Earth only in the Tunguska meteorite, trying to poke wires through some microscopic orifice using only tweeeeeeeezzzzers crafted from titanium, putting those wires in there. NO. It's MUCH eeeeeeeeeeezzzzzzzzzzyyyyyyyer than any of that.

Cars are built out of ASSEMBLIES. Whole finished blobs - engines, harnesses, seats, dashes, WHATEVER - are delivered to the vehicle assembly plants, in formats where the assy line workers can build them into CARS in the takt time https://en.wikipedia.org/wiki/Takt_time allotted. Believe it or don't, this time is VERY short. Those d00dz don't have long to do what they have to do. It's SIMPLE, fast, and EEEEEEEEEEZZZZZZZZZY. Gotta be, or no cars would EVER come off of the line.

In the case of what you're trying to do, there's a harness in the engine compartment, and another in the interior. Amazingly enough, those must actually arrive at the same place, and PLUG INTO each other, and moreover, do so within the takt time (see above) on the production line they're expected to be built in; and furthermore, to do so, HUNDREDS OF THOUSANDS OF TIMES each year, without error. How simple can it get?

Well, in this case, it's so simple, you'll SPANK YOURSELF when you see it. It is, there's a sort of U-shaped retainer in the interior, that holds the cabin side of all that in place. It's INSIDE the car. Once you pop that clip off, the whole harness is then free, and you can pull it out towards the windshield cowl (the outside), after unplugging it from the things it goes to on the INSIDE of the car. (ECM etc.)

So, look INSIDE the car, and find the clip (it goes completely around the outside of the pass-through), slide it upwards, and magically remove the whole deal, like the wizard you have just become.

Put all of that harness, plus whatever sen-sores and whatever else it plugs into, in a box somewhere, against the possibility that you may need it someday; as I did some years ago when I moved from the deep South to California and SUDDENLY needed my car to match its original build. None of it is needed for ignition, gauges, AC, or ANYTHING ELSE; it is a completely stand-alone assembly specifically devoted to the computer-controlled carb system. Not needed for anything other than that.

 

Things are changing sofa. What if I can convince the AI robot on the assembly line to believe that it's a 10,000-year-old gnome with tools forged in the fiery....

 

Okay, thank you! So just to be clear, the wires going through the bracket in my first picture are NOT the same as the wires going through the fender well in the second? These wires were plugged into the ECM and I unplugged them thinking I would just be able to pull them through the fender well.

 

That is not correct.

The wires going through the windshield cowl behind the kick panel in the interior, and behind the inner fender liner on the exterior, ARE the same harness that appears in the engine compartment, and that harness DOES plug into the ECM. However, the "wires" DO NOT "pull through" the windshield cowl. THE WHOLE HARNESS does, including the black plastic thing, by unclipping the large U-shaped plastic clippy thing on the interior side, that retains the black plastic piece in the cowl.

 

Okay, I think I may have just used the wrong verbage for this. I was trying to remove the HARNESS from the vehicle, and I had already unclipped the U-shaped clip. I finally found a video of a guy doing this and I realized that instead of trying to pull the black piece out, I should have been pushing it in toward the fender well. I will give it another go tonight and let you know how it goes. Thanks so much!

 

I got it out! I guess you can say I'm the kind of guy that pulls on a door that says 'push to open.' Just had to go the other direction with the wires. Thanks a bunch.

 

I know this thread is a month and a half old, but I recently got the car running and now I've got a new issue.

The ECM harness is completely removed from the car. As a result the VSS connector was also removed from the trans, so now I have no input to my speedometer gauge. Is anyone aware of a wiring kit that I can run directly from the trans to the gauge? I'd like to buy a new wire rather than trying to tear the old harness apart just to get one connector out. Hopefully that makes sense.

 

'86 would have had an electric speedo, and I believe an '86 V8 would have made use of a buffer box alongside the ECU... if you still have that buffer box kicking around, you should be able to use it without an ECU.
In short, your gauge is expecting a signal of 4004 pulses per mile (or thereabouts) to read accurately. The buffer box takes the wave signal from the VSS (signal depends on your rear gearing and tire size), processes it to the proper ppm, and sends it to both the ECU and the gauge, and possibly the cruise control computer if so equipped. HERE is a thread I found on the 86-89 buffer box, with a wiring diagram and a labelled picture of a buffer box. You COULD also go out and buy one of the Dakota Digital VSS converter boxes, I think they run around $100-$150. Lotta folks with factory buffer box setups run those when they do transmission swaps, but if you still have the factory trans, you could probably get away with just hooking it back up (minus the ECU signal wire).

 

The 1986 Camaro has the VSS mounted to the forward side of the speedometer. The 1986 Firebird has a VSS clamped into the tailshaft housing of the trans, just like the old speedometer cable thimble would have mounted.

The Firebird has the yellow VSS buffer box mounted in the lower portion of the dash on the right side, forward of the relay panel. At least that's where it is on my '86, along with the power antenna relay, and a few other random electrical items. It is accessible from the ECM area, but to really provide slack for its harness (and then put it back properly).the relay panel has to be exposed.



The buffer takes the crude semi-sinusoidal pulses from the VSS and creates a DC pulse (square wave) that the ECM can count. That signal is also split, divided, and sent to the cruise control module, and also to the speedo head.