Just for fun (and a learning experience), I tore into my old alternator again to look at the rotor slip ring (as I learned what it was called). It was quite dirty from brush dust. I used solvent to get some of the loose crud off but as the photo shows, it still has "arc" on it. "Arc" is the black ring between the copper rings where the brushes make contact. The guy in the video said that rotor slip ring is good if you still have copper on it. Judging from his video, there should be plenty of copper on this one. However, it is highly advised to remove that "arc" with some sandpaper to expose the copper. I didn't do that when I put a new terminal block and brush assy back on. Tsk, tsk on me. Either way, it still remains a mystery as to why one brush had considerably more wear than the other brush. I wouldn't even know if this is normal or not. I wouldn't think it would be normal but I'm not an alternatorologist.

 

Here is an AFTER photo after taking some sandpaper to it. Not perfect but considerably better.

 

OK, the dash gauge is back to dancing again. At least I know it's not the alternator. It steadies up rock solid after driving it a half mile or so. This, after driving 20 miles yesterday making four stops at various stores with no sign of fluctuation throughout the trip. However, an old problem has reared its ugly head again. It's the initial problem I described in the OP of this thread. Yesterday when I took my trip, it would not start on the first attempt. Again, the engine would begin to crank for a split second and then nothing. Today, it did that three times before firing up on the fourth attempt. I can't win.

Now, I was playing around near that plug/harness that goes in the regulator before I took my trip today. I didn't unplug or replug or unscrew or rescrew anything. But I was moving the wires while messing around with the vent tube going in the air cleaner (it keeps falling out of the hole near the grill). And I also rotated the mount that the relay is attached to cuz it was crooked. Did that have something to do with it? I have no fricking idea!

That said, my next step will be to make a new wire harness for the regulator. New wires, new connectors, perhaps even a new plug. But this time, I'm running my power wire direct to the battery and bypassing the relay that I have connected to a switched circuit (the cigar lighter in the cab fuse box). I know that will drain the battery but for testing purposes I will just disconnect the power wire from the battery each time I park it for the day. I don't think I'd drain the battery enuf just going in and out of a store (correct me if I'm wrong). If after that solves the problem then I can redo the relay or hook up a switch somewhere to block that power wire. If all this fails, then I think its time to chase after another PCM with a working regulator. I don't know what else to do. Thoughts?

 

Check connections at the battery. Poor ground will do that.

As I recall, your battery and starter are both relatively new??

 

Checked connections this morning. Battery is 1.75 years old. Starter is OE. 30 years old. I removed the starter a few months ago and cleaned the connections.

I have the regulator harness and relay pulled out of the truck. Tomorrow morning I will make a new harness with all new parts (wire, terminals, plug connector, fuse, all of it). Truthfully I don’t have much confidence. I tore the old one out today and it looked perfectly fine all around. But I will bypass the relay and go direct to the battery just to see if that makes any difference. I suspect not.

There seems to be decent options on Ebay for used PCMs (my specific PCM). Anywhere from 30-90 day warranties from veteran, highly rated sellers. One claims all his PCMs come from wrecks. So presumably the thing was working fine before they piled it up.

 

Any thoughts HY?

UPDATE
I completely remade a new voltage regulator wire harness. All new wire, new terminals, new plug connector (to the regulator). All connections crimped with heat shrink or wire nutted. Nothing soldered. All wires checked positive for conductivity. I totally removed the switched circuit relay setup and instead went direct to the positive terminal of the battery for my regulator power source. I didn't even add an in-line fuse. I know this drains the battery but I want to keep this as bare bones as possible for purposes of testing.

RESULTS OF 7-MILE TEST DRIVE
Truck fired right up on first attempt. Gauge needle went straight to its "normal" operating position. Needle stayed rock steady throughout the test drive. No headlight flickering.

MEASURMENTS
Some interesting readings: Before beginning work, I measured my battery a few times (hadn't run since noon yesterday). I was getting 12.72v each time I checked. After I made all my connections, I put the negative battery terminal back on the battery (I had it off while I worked). I checked voltage right away and it was 12.35v holding steady. Simply hooking the system up immediately drained 0.37v. No idea why. After firing up truck I was getting 14.3v on the battery at idle. Upon returning from the test drive I was getting 13.98v at idle. After I shut down the truck, I was at 12.75v and decreasing.

PLAN
I will check the voltage at the battery every hour just to see what it's doing. I do plan on disconnecting the battery ground terminal at least when I am done using the truck for the day so as not to drain the battery. I'll continue this regulator set up until it either fails or demonstrates it has solved my voltage fluctuation problem.

 

Why not hook regulator power to a switched ignition feed? Maybe something right off the ASD relay?? Having it 'automatic' makes life a lot easier.

 

I will definitely hook the regulator power to a switched ignition feed like I had it before. The only reason I haven't put it back now is because I'm in test mode. I want as few connectors, wires, terminals, and splices as possible to have the regulator function properly while minimizing "possibilities" of problem areas. Bare bones all the way. Once I feel the problem is solved I will add back components. In fact, I already added back a fuse link. It bothered me that I didn't initially put that back. I had a '69 Dodge 318 fry on me back in the early 80's from an electrical problem. It never recovered. Been skittish about electrical mishaps since.

Anyway, since replacing all the wiring, connectors, and terminals plus removing my ignition feed relay I have gone on 6 test drives over 4 days. Results have been perfect every time. Zero voltage fluctuation. zero gauge dancing, zero light flickering. And this is about the time it starts screwing up in the past when I would "fix" the problem. I'd like to go another week or 10 days like this without any trouble. Then I'll add back the ignition feed and see if it continues to function properly. For now I just disconnect the battery...those clamp style batt terminals are coming in handy.

I closely inspected the old components and splices from the old harnesses. I did not see anything obvious. But I cannot see inside those connectors without tearing them apart (the regulator connector is rubber molded). It must be said when I initially installed that external voltage regulator, I purchased a kit that included pre-made harnesses and plugs. It's what people do when they don't know what they're doing because it comes with nice instructions and videos showing how to hook it up. I'm long past that learning curve now so I get my own components and build my own stuff now. And no more soldering! I am crimping everything.

 

8 test drives over 6 days to test the new wire harness for external voltage regulator. No voltage fluctuation, no light flickering. Perfect so far. Gonna go a couple more days and if still good then I'll hook it up to a switched circuit. Still getting problem with multiple tries to start the truck. Probably from me disconnecting and re-connecting the negative ground terminal all the time. Tells me the bad connection is there. I'll address that later with a new or repaired cable.

 

UPDATE

Test drive #12 complete. Zero voltage fluctuation, zero light flickering, zero issues. After 12 successful test drives over 8 days I felt confident enough to hook it all back up to the ignition system. I used the old relay and relay connector. Truck fired right up. Took a test drive...zero voltage fluctuation, zero light flickering, zero problems. So far (I stress so far) it seems the relay setup was never the problem. Time will tell for certain.

If this success holds then I place the voltage regulator connector as my prime suspect as to why I was having all this trouble over the past couple/few years. I've changed and/or reworked so many things that seemed to work but for only a week or so. That regulator connector is about the only thing I never monkeyed with. Guessing whenever I'd rework the wiring that connector would move enough to "fix" itself" albeit only temporarily. Cheap Chinese CRAP!