I recently bought an 83 Z28 with an LT1 swap from a 93 Camaro. The car sat around 2 years before I bought it. It has some issues but I got it cheap. There is a leaky exhaust gasket on the passengers side, a possible misfire and is currently running pretty rich. I am going through the basics of changing fluids, adding some fuel/intake cleaners, etc. It bogs down when I accelerate to quickly and has a nice gas smell, so obviously running very rich at the moment. The tach/speedo are all over the place so something isn’t right there either.
I have a couple of questions and am attaching some pics regarding some connections that do not have a home in the engine bay and would like some input on the plug I pulled from the 7th cylinder. It actually looked better than what I expected.

 

That one loose connector looks like the usual "mystery connector" people always ask about.

Pink/blk and blk or blk/wht wires?

If so, since those wires are keyed 12V and gnd, the best guess out here is, that it was used at the factory where they built harnesses dashes and ECMs, to test those parts of the system without it being installed in a car, before it left the electronics factory and got shipped to a vehicle assy plant. That connector would have supplied the 12V power.

The other connector with the one yellow wire and all the tape, can't tell what that is, besides that it looks like it's been hacked on quite a bit. What's the other wire?

The spark plug looks suspiciously like ... a spark plug. Not sure what you're asking about that?

 

Thanks for the info. My experience has been with 5.4 and 5.0 V8s the past decade or so.

The plug doesn’t look as fouled as I expected based on how rich my mix is right now.

 

The harness by the brake booster is the 12v power?

The black box at the top of the engine bay has a bunch of cut wiring. I believe that is emission stuff, but I could be wrong.

The other harness is at the base of the steering column. It has the blue end.

 

Not when in a car; only for testing at the wiring factory.

What color are the wires in that other connector? It's not "blue"; only the little silicone seal on it is blue. The connector is black or dark grey.

What's the little plastic cube doing dangling up against the header tube?

 

Looking as closely at that other connector as the photo allows, it looks kinda like a coolant temp sensor one. If it's that it'll have 2 small pins and the body of the connector will be a kind of "squoval" shape.

That fan relay looks kinda hackjob-ly as well. Might want to get a relay with a sealed connector and its pigtail and de-sodomize that a bit.

 

I also found a squirrel nest inside the blower motor.

 

Yup, looks like the 12V connector they used for testing, and the CTS connector. Might want to find the CTS and plug that one in.

The cube thing in your hand, I have no idea what it is. I'm pretty sure though that dangling up against a header tube isn't going to do it any good. Tie it up somewhere safe and out of the way.

 

Agreed, I’ll zip tie it to something out of the way if possible.

The engine coolant gauge works and the fans kick on. I’ll look in the morning to see if the cts sensor has something plugged into it.

 

Not sure that either of those things is necessarily connected to the coolant temp sensor.

The gauge has its own sending unit in our cars, and if that's still active, then ... the CTS could be doing absolutely anything, or nothing whatsoever, and the gauge would still work fine.

Looking at your fan hackjob, there's no telling what's working that. I'm frankly amazed that it works at all. It probably won't for long, but it's encouraging that it does now, FWIW. But again, still no guarantee that the CTS is functioning; if the fan is working off of a temp switch, like it does in alot of our cars, then the same logic applies as to the gauge.

Best to find the CTS and plug the CTS wire into it. If nothing else, the car will probably run A SHIPLOAD better, and use A SHIPLOAD less gas.