Captain Obvious

Yeah, I think I would recommend running a return line, but that (like a lot of other details) can wait. I just want it to idle correctly for now! Haha! I'm no regulator expert, but I'm not a big fan of dead-headed systems in carb applications. This non-expert would prefer a bypass regulator system with a return line.

I have very little doubt that things will be a whole lot better now, but after four pages, I just want to hear it from you to be sure!

If the blue wire is disconnected, the rest of the ignition module is just along for the ride. It'll still be reading the input signal and switching it's output stage, but that output stage will not be connected to anything, so it will have no effect.

Well that vacuum connection you are using now is full manifold vacuum, but the system was designed to use a ported source that peaked advance at light cruise throttle (slightly above idle). With your direct manifold vacuum source, you will have peak advance at idle, and it will drop from there. I'm no timing expert, but I'm not sure that's what you want. And I don't think your vacuum connection is really a remnant of mixing and matching parts from different years. I think it's a remnant of snapping off the original ported vacuum nipple and then looking for some place else to connect that vacuum line. Either way... So when will we get an idle report to see if taking that nail out allows the front carb to operate properly?

And can I just point out that when I said "I'm thinking that something within the carb itself is keeping that front throttle butterfly from closing completely"... I nailed it! HAHAHAHAHA!!!!!

Well THERE'S your problem!! Yes, that nail was holding your butterfly open and not allowing it to close completely. Some answers to additional questions: That hole is intended to be a ported vacuum source to drive the distributor advance. There is supposed to be a vacuum tube nipple pressed into the carb body that allows you to connect a rubber tube between the front carb and the distributor advance diaphragm. It appears someone sheared the nipple off and decided to plug that hole with a nail instead. And about the "insert grease" engravings... It appears that someone drilled little holes in the carb mounting face with the intent of using them as lubrication grease ports to lube the throttle shafts. Probably a waste of time, but since they are sealed off by the gasket between the intake manifolds and the carb faces, it probably doesn't cause any harm either. So for both of those items... THAT'S something I've not seen before!! Bottom line... Plug that vacuum nipple with something that does not stick down into the carb throat and I bet your idle issue will be pretty much taken care of.

Well I stand by the belief that the problem is in front if the transmission somewhere and not internal to the tranny itself. Is this an accurate description of what's going on in your sound byte? Put it in first and rev the engine with the car not moving. All quiet. Let the clutch out a little bit and let the car creep forward. Push the clutch in and come to a stop with it still in first and rev the engine. Unpleasant noise. If that's what's happening, I really don't think the problem is inside the tranny case. I think it's something in the clutch system. I don't have any strong theories about exactly what is going on, but I think something is chattering around in there. Disk on the splines as ZH suggested above? Is there any possibility the starter is involved? Something shifting somehow and the starter gear is buzzing against the ring gear on the flywheel? Seems hard to come up with an explanation of the sequence of events, but just tossing that out there as something to think about.

Well I think you're being a little too hard on yourself with the dunce moniker. You had a problem, searched for the root cause, and found it. Right? Note that I was going to suggest you check the fuse, but instead suggested the more general "you'll need to start poking around upstream". Of course, the fuse is part of that investigation. But whatever... Your radio works now. Good deal!

Sorry. I've really been meaning to get on top of my A/C project, but time keeps on slipping, slipping. That said. let me clarify something... I mentioned that I had collected all the stock parts I need to put a system into my car, but I am still opposed to using the original compressor. Even if I use the original hard lines, etc, I still plan to use a newer ubiquitous compressor from something easy to find. And Dave WM has suggested to me that a newer parallel flow condenser is better for R134 than the original serpentine version. Apparently R134 likes a parallel flow, while R12 likes serpentine. So now I'm thinking I would try to retrofit a newer parallel flow condenser instead of the original. But all of this still assumes that I actually get back to working on it...

Haha!!!

And some of the aftermarket radios do make use of some of the illumination stuff in some way. I don't see any mention of it on the wiring diagram from Kenwood above though. What Kenwood are you using? I'll see what I can dig up to be sure.

They changed some of the wire details over the years, but for 77... The blue is +12V power in. It should be hot when in ACC and ON. If it's not, you'll need to start poking around upstream and find out why. The black is ground. Should be hard ground at all times. Black/red is the original speaker output. Green/White is illumination bulb high side. Goes to the headlight switch. It should go to +12 when the parking lights or headlights are on. Red/Blue is illumination bulb ground side. Goes to the rheostat. It should read a variable voltage depending on where you have the dimmer knob turned. At full brightness, it should read zero volts, and at full dim, it should read close to 12V.

I thought your tolerance for no A/C got depleted that year you tried to ice bath yourself while driving. Wasn't there some goofy thing with umbilical cords to a cooler of ice water and a pump?

Maybe it's just semantics or wording, but what you have described really makes no sense. Let's start with a premise - "If the car is not moving, and the transmission is in a gear (any gear), then nothing inside the transmission is spinning." With that in mind, when you are sitting still, there really isn't any difference in what's moving inside the transmission regardless of which gear you are in. Neutral is different, but all the gears (including reverse) should result in everything inside the tranny to be stationary. Maybe the shift lever is buzzing on the worn bushings or against the tunnel somehow? Maybe the shift rods inside the tranny are buzzing vibrating when in first or second. Unless I'm misunderstanding the issue (which is totally possible) then this cannot be a bearing issue inside the tranny case.

Hahahaha!!!! I'm totally stealing this.

Glad you got the hazards working! And what you found makes perfect sense. I was thinking it had to be inside the switch itself, but that's not true. It had to be either inside the switch, or the downstream wiring until it joined with the firewall harness. Good work! That corrosion is from your heater core leaking 20 years ago. Most 260's and 280's have some green fuzz growing in those connectors.

Sorry Matthew, but I haven't made any significant progress with my A/C. I have collected all the stock parts I need to put a system into my car, but other than collecting parts, that's it.

Glad it was that simple despite the super coincidental nature of the failure. Occam's razor. So you want to send me your dead tach so I can open it up on the operating table and do some reverse engineering?

Looks great. Doesn't have to take a lot of tension. Just has to keep the ends from flopping around out in the wind!

No biggie. The only reason I could tell it wasn't a ZX was because of the location of the BCDD.

So I (actually) read through the details of the thread this time and I think I have a better understanding of what's going on... The issue you are having is that the steering SHAFT that runs through the center of the steering column assembly does not seem to be grounded. The outer shell may be (or may not be), but that isn't good enough to get the horn the actuate. You actually need the rotating steering shaft in the center to be grounded. So, I agree though... I would expect the center shaft to get grounded through the roller bearings, but maybe not? Have you tried grounding the outer tube with a dedicated wire and seeing if that makes your horn work?

i like it!

If you've got play like that in the AFM, I'd just replace it with another one. Then after you've got it fixed, I'd autopsy the old one. Grind the stripped out screw heads flush and then pry that cover off. I would expect the sealant to put a fight though. I'd be interested in seeing the insides. It seems hard for me to believe that a bushing has worn out so much there is visible slop in the arm. Wonder what happened and why!

They were:

I have very little 240 experience, but I wouldn't expect the steering coupler to be the "planned" source to ground the steering column. I would expect the steering column to be grounded through the bolts that hold it to the firewall or the bolts that hold it up to the underside of the dash.