If the voltage regulator is not getting a good ground, it will not give a consistent output. That’s why things will flicker!
This isn’t flicker though, not an intermittent on/off sort of thing like one would expect from a bad ground or other intermittent short/open circuit. This is a regular, repeating wave function with the lights getting brighter and dimmer. And the timing of it doesn’t track with the engine rpm. It just screams of a capacitor charging and discharging.
I will definitely check all grounds I can find. Securing the grounds and taking the choke feed off of the ignition coil connection, I am guessing that will solve the startup issue. But I will be surprised if that resolves the pulsating electrical issue. I hope it does. But I don’t expect it will.
Checking the grounds won’t do any harm at all, however I still think I’d try the alternator first.
Inside your alternator there are a number coil windings and associated components.
If one of these begins to fail, the output from the alternator will seem like a wave as it constantly rotates past the weak part.
Is there any way you could borrow an alternator from somewhere to try it ?
I will have to check with a friend here in town, if anyone I know has a spare alternator it’s him.
With the hesitation on acceleration bothering me, I went ahead and pulled the fuel feed off at the tank side of the filter (which is brand new) to check what came out. Tons of fuel! Poured out of the line. Last time I did this I jacked up the front end hoping that the fuel wouldn’t come pouring out, and not a drop did. Stupid me tried it without the jack this time. Not so great. But I had put a bottom 1/2" of a plastic cup under it, which caught enough (before it started pouring on the floor) that I could see the fuel is fricken disgusting, little chunks of crap in it. New tank and lines are here, just gotta get em in.
Then I went ahead and replaced that ratty tach/temp/oil wire with the brand new one. The plug didn’t connect to the plug by the firewall nearly as nicely as I would like it to. I had to jam it on extremely hard and even then there’s about 1/8" gap between the two pieces of plastic. The gauges are reporting so I guess the electrical connection is working. Well, dunno about the tach because…
New symptom after that is now it turns over and over and over but never fires at all that I can hear. :-/
I went back to google to try and find a good write-up on how to check a voltage regulator and found something that I like mostly because it solves the same problem I have by addressing the same component I suspected all along, the capacitor on the voltage regulator. Post 15, the last post on the first page, of this thread here:
http://www.allfordmustangs.com/forums/classic-tech/93261-1966-mustang-charging-systems-problems.html
Can’t wait to get back in there and see what happens if I try and start her up with that cap disconnected. Based on the amount of AC ripple I was seeing, I doubt that cap has any life left in it. Not sure which style of cap it is, but if it’s an electrolytic, the conventional wisdom on those is that they should last as long as 15 or 20 years if used consistently and more like 10 years if not used much. I’ve replaced a zillion electrolytics in old tube amps, old amps from the 60’s, some of which miraculously still have the original caps which still sorta work. Always a good routine maintenance thing, it’s like the new plug wires or new tires of the amplifier world.
Totally gonna pull that cap and punch it in the nose. Man I hope that solves all my problems.
“lmfao” as the kids say.
How’s that A terminal look to ya?
Omg.
Now the question is, try and clean it up with a wire brush or something, or just go ahead and pitch it?
I’m curious about the connector too, if it’s corroded to hell like this too. And if that means it needs cleaned or is beyond repair.
Electrical is in my opinion about the 5th most important thing going on with a car as far as safety goes, with tires, steering, brakes, and fuel ahead of it. I’d rather err on the side of caution if the cash outlay isn’t prohibitive.
Oh and I forgot to mention, I also pulled the battery and rotated it 180 degrees so now there’s not that tension on the negative battery wire. :thumbs up emoticon:
Another question re the regulator. Replace with solid state, replace with mechanical, or just clean up the terminals and see where that gets me? The cap is dead, it reads as infinity ohms resistance, so it wasn’t doing its job anyway. I’m guessing part of its job is to reduce or eliminate arcing across the contacts as they open and close, so… I think replacement is probably the way to go but am open to input.
I’ve read some people say switching to solid state solved problems and others say that they switched to solid state and burned out 3 of em in a matter of hours but a mechanical one worked fine for years after that… as usual, hard to know who to trust on websites I’m not familiar with.
Thanks guys!!
2-3 more posts about the subject, it might fix itself! (J/K) 
Have you noticed all the battery trays and fender aprons rusted out? Partially because the mechanical points stuck in the old style voltage regulator and boiled the battery over.
Get an Echlin (NAPA) or Motorcraft electronic regulator. Clean the female spade terminals, pull the alternator and have it checked at an auto parts for s___ and giggles.
I know I know, I talk too much and ask for too much help. If it was something cheap or irrelevant I’d just dive in and do whatever I felt like doing, but since it’s an expensive and very awesome car I don’t wanna screw things up by not asking advice as I go. Remember the time I pulled my distributor out to take pics of the points? Lol
Fender aprons aren’t rusted at all, battery tray is rusted a little but not badly at all. I’m going to be switching to an electronic ignition (Ignitor II) very soon, so getting into a solid state regulator does also seem the way to go.
I like NAPA, that’s where I’ll go. I’m assuming they can test the alternator but will call first and see before I go pulling it out.
To put in a new alternator, or put this one back in, I’m gonna need a belt tensioning tool, right? No spring-loaded tensioner pulleys at work here. As always, I want to over think things and plan ahead so I know what I’m getting myself into. 
Thanks again!
Scott
Alternator is out of the car as of a few hours ago. Seems nice. Has a sticker on it that says its a reman. Has very little resistance to spinning, less than I would have expected.
Talked to local NAPA earlier today, they’ll test it for free. They also have the solid state voltage regulator and also the wiring connector in stock. Probably end up buying just the regulator for now.
Very curious to see how the alternator tests. Good, I hope, based on what they cost.
Only if you’re really fussy.
As a normal rule of thumb, if the belt doesn’t deflect more than 3/8-1/2" on the longest run it should be fine
A dab of dielectrical grease on the regulator plug and between the base and the radiator support would be a good move.
Alternator tested at NAPA : passed. No problems
New solid-state voltage regulator : purchased.
Also picked up some dielectric grease which I didn’t own, and a new plug just in case the existing one is beyond hope. I’m really thinking it would be best at this point to just replace the wires that run across the bottom of the radiator, just because. Better safe than sorry, right?
So glad there’s nothing wrong with the alternator!
FIXED.
Last night I put the alternator back in, and put in the new solid state voltage regulator. Used dielectric grease anywhere there was a metal-on-metal electrical connection. Made sure the ground connections from alternator and battery negative were totally solid. Got the alternator belt to what I think is an appropriate tension.
Went to fire it up this morning to see if my work had paid off, and it was doing the same thing as before, cranking and cranking but not starting. Eventually I figured I should try using my remote start button to fire it from under the hood so I could do the spark gap test on the coil wire to make sure I had juice. Disconnected the wire from the ignition and connected my start button. Went to test if the button was working and THE CAR FIRED UP INSTANTLY. Ran like a top.
I disconnected the button and reconnected the wire to the ignition switch, and turned it off and on several times since then and it works like a champ.
Drove to pick a couple things up and tested if it was still bogging on acceleration. Not in the slightest. In fact I accidentally chirped the tires the first time I tested. I swear it was an accident.
Now everything is peachy. I didn’t see any pulsating in the lights anymore, but can’t be sure the problem is solved yet until I drive around a bit more. At this point it could just be that the battery is still low from all that cranking without starting, so the regulator is never turning off the charge. I did keep it on a float charger all along, so the batt was over 12v this morning. So maybe it’s all good.
Gonna go for a longer drive now and see how it goes.
Thanks for all your help guys! Great to have my cat back on the road.
Oh, and I did go ahead and hook the choke up to the stator post. Gotta be better there than on the coil connection at the solenoid. And I verified correct operation once it started up.
Woohoo!!
Yep, totally fixed. Drove around for over an hour, no pulsating electrical, then parked for a few hours, fired up no problem, drove for a half hour or so, no pulsating lights. Problem solved!!
Also during that first hour of driving, ran the tank lower than I ever have, into the red but just barely. When I took the gas cap off (push-on, key locking replacement) got the biggest whoosh I ever had as the tank pressure equalized. It’s the same tank that was in there since winter, old and all, with Stabil in it. Put in 4 gallons of 93 octane and man was it a night and day difference, just had noticeably more get up and go. Not sure if that’s cause of the new gas or equalizing the pressure or both.
Anyway long story long my cat is back in action and better than ever. Can’t wait to get on to the next projects, and there are plenty of em.
:appropriate emoticon:
(edit)
By the way when you hook up a new gauge cluster feeder wire, don’t screw up and attach the tach feed to the temperature sender. Cause it kills the temperature sender.
Good thing I already replaced the sender on my Bronco so know how to do it without asking for help yet again.
Glad you got it solved.
Sometimes it can be the most innocuous thing, and the cure is found by accident !!