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1986 K30 - Rapid Learning

Get 'er cleaned up and solid.
Those 10/12SI alternators aren't wired that way. It needs power on both of the terminals in the small plug, BUT one has to have less voltage than the other ( battery voltage). I know that sometimes just the bulb in the charge light makes enough resistance to make it charge, but I may be remembering it incorrectly.
I think you might have that backwards. I think the CS alternators need the resistance wire or bulb. I have a 12si alternator.
 
I think you might have that backwards. I think the CS alternators need the resistance wire or bulb. I have a 12si alternator.
I am fairly confident in my information on that. As @imiceman44 said, the CS series has remote sensing, not all factory installations used it, but they were capable of it.
 
Those 10/12SI alternators aren't wired that way. It needs power on both of the terminals in the small plug, BUT one has to have less voltage than the other ( battery voltage). I know that sometimes just the bulb in the charge light makes enough resistance to make it charge, but I may be remembering it incorrectly.
After doing some looking I was wrong. You do need to have #1 terminal connected to a switched 12V source. If you don't have the idiot light, you may need a diode on that wire to keep it from back feeding the ignition and keeping the vehicle running.

Apparently you don't technically have to have the #2 wire connected. On the SI alternators, the remote voltage sensing is optional. Without it, the alternator uses the charging post to sense voltage.

I was reading all this here: https://alternatorparts.com/faq.html
 
Good info.
@shima needs to check the bigger wire in the 2 wire plug for voltage with key off then on. No voltage off, and should see battery voltage with key on.
 
After doing some looking I was wrong. You do need to have #1 terminal connected to a switched 12V source. If you don't have the idiot light, you may need a diode on that wire to keep it from back feeding the ignition and keeping the vehicle running.

Apparently you don't technically have to have the #2 wire connected. On the SI alternators, the remote voltage sensing is optional. Without it, the alternator uses the charging post to sense voltage.

I was reading all this here: https://alternatorparts.com/faq.html
And I have seen plenty of SI alternators setup with one wire on that plug.
At first it puzzled me then I learned more about that
 
And I have seen plenty of SI alternators setup with one wire on that plug.
At first it puzzled me then I learned more about that
I still think in a scenario like mine with a bunch of loads that aren't part of the factory harness as well as the non-factory charging wire , it's a good idea to run the #2 pin to the battery and/or where the added loads are connected.
 
Hmm I am not understanding, #2 pin in small plug goes to voltmeter or charge light, no ?
The #1 pin in plug is from ignition switch power.
 
Thanks for the responses guys! I have some reading to do before I can fully understand your comments and suggestions... I'm going to start with the FAQ link that @mrk5 posted earlier.

Last night, I finished installing the new battery cable. The pigtail is just disconnected right now... I wrapped the exposed end in electrical tape.

The truck's starter sounded great when I fired it up, so that's awesome. Unfortunately my voltage reading with the truck running was just below 12V. I had the headlights on when it was running. I also blipped the throttle a few times and tapped the alternator with a hammer.

So next steps for me are to do some reading on that FAQ page and then revisit your guys' responses / comments.

I also picked up some things from Harbor Freight in case I need to do any work on the electrical stuff. I call this the, "I have no idea what I'm doing and hope this is a good start" package:

PXL_20220513_015517663.jpg
 
good start, what diameter is solder ? lead free ? do your self a favor and get some Klein crimpers, Lowes has them for reasonable $.

I have these 2



The blue handle are adequate.

You will see the difference, if you get any time on the HF crimping tool.

going to need some 10ga connectors (yellow)

I still think you have a blown fuse link, but I'm sure you'll figure it out.
 
I have those too, but most people won't spend the money for them. A set of 3 from Packard Electric. The 2 I linked I keep in my travel kit.
 
It looks as though we're back in business.

I read through all of your guys responses (a few times) and looked at a couple of diagrams. I also read through the FAQ that @mrk5 posted. I'll be honest, a lot of the FAQ stuff on how alternators work was pretty difficult to understand... but I think I still learned a thing or two.

Anyhow, I decided to reconnect everything first and see whether it made a difference. My solder job was pretty terrible on the alternator wire... there was a pretty big lump after everything was done. It was actually big enough that my 1/4" heatshrink wouldn't fit over it. I sliced the heatshrink to make a couple of flat sheets and then used twistie-ties to keep them in place while putting a lighter to it. I know it came out pretty ugly so I wrapped it in electrical tape after that. Probably worth simply redoing it later with larger diameter heatshrink.

Once it was all connected I fired up the truck and took a voltage reading. It was bad - right at 12V (maybe a little over). Last night, the almighty YouTube algorithm suggested this basic ChrisFix alternator video and I watched it. I decided to go through some of the tests that he has in there because he had a bunch on voltage connectivity and I thought it may help me prove @Wes Harden's guess about the burned up fusible link. All of the tests checked out fine.

I decided to just double-check the voltage at the battery with the truck still running. It actually read 13.1V! I thought hey it's charging although it's weak. Then I remembered that I had a bunch of accessories on... headlights, heater, radio... so I shut all that stuff off and read it again. The voltage jumped up to 13.9V!

In all honesty, I think everything was fine once I got it all reconnected again. The weak voltage reading at first was likely due to me not having had revved the engine up yet. A lot of the voltage connectivity tests in the video have you rev the engine up, so I did that while going through the tests. That was likely all that was required to get the alternator charging correctly.

I took it for a drive afterward. It was was the first time I had moved it out of the garage in a couple of months. I washed it at the local spray bay and then filled up the gas. Two things that I noticed while driving it that I want to mention here as "notes to self"... the clutch pedal would sometimes have zero resistance in it and would just fall to the floor. I presume that means I need to bleed it. Second, when cranking to start the truck up (while it is warm/freshly shut off), it will immediately sound like it is firing off but wont actually do it. Then it will crank crank crank for a while and eventually fire off a second time and actually start. There is an aftermarket fuel filter right by the carb that I think I will replace and I presume there is a second one on the frame rail somewhere... I think I'll just replace both.

Thank you guys for all of your help and for getting me on the road again. This is a huge boost to the driveability of this truck.
 
Glad you got the alternator figured out and got a chance to go for a drive.

Your starting issue could be a vacuum leak.

I'm pretty sure carburetor trucks only have a fuel sock in the tank and a filter on the carb inlet. Unless someone added one aftermarket.
 
I haven't driven the truck much since replacing the battery cable. I wanted to just get it out and knock the cobwebs out... so I took it to Home Depot last night. After that, my girlfriend and I got it out on the highway and I was able to floor it a few times. Other than the loose steering, it felt great! lol

I left it out in front of my house in an effort to make myself drive it anytime I need to go somewhere. It really deserves to see more regular use than I've been giving it.

PXL_20220721_033336045.jpg
 
It has been a while since I've updated the thread...

I took the K30 out to do some truck stuff a couple of nights ago. A buddy just moved back to Denver and needed a hand moving his box spring and mattress from a storage unit to his new house. So, I offered to help with the K30...

We had a cold snap in Denver a day or two before I first tried helping him out. I primed the carb with fuel per usual and tried to fire up the truck. It cranked a bunch but wouldn't fire. I had the choke pulled all the way out and my foot lightly on the throttle. I tried again and it fired off but died - I guess I didn't have my foot on the throttle hard enough. After that, the battery died. I tried jumping it with my K5 and I still couldn't get the engine to turn over. I took the battery to AutoZone to have it tested and charged.

A day later I tried again with the charged up battery. I got a few cranks out of the battery before it died again. My buddy jumped me and we actually got the truck to fire off and idle. From there we were able to successfully complete the mission - here are a couple of pictures:

At the storage unit, all loaded up:
PXL_20221109_020308685.jpg

At his place prior to unloading:
PXL_20221109_022116261.NIGHT.jpg

Anyhow, I was proud of it for making the trip. I also felt horrible about how little attention I've given this thing over the last couple of years. I am in a pretty good spot with my daily driver and the K5, so my plan is to park the K30 in the garage this winter and just work on it all winter long.

Here are my top 5 items in prioritized order:
1. Oil pressure gauge doesn't work.
2. Voltage gauge doesn't work.
3. Starter shims need adjusted (or starter needs to be shimmed)... I am getting the awful buzz sound more often now when I crank on it.
4. The carburetor isn't tuned / adjusted for Denver's elevation.
5. The steering is incredibly loose.

If I manage to fix those 5 items, I'll be able to start the truck more easily and will be assured that I'm not hurting it when I drive it. That's goal number 1... just want this thing to be reliable first and foremost.

My girlfriend's XJ is having a pretty bad fuel delivery problem, but once I get that sorted then the plan is to have the K30 take over the garage all the way until spring of 2023.
 
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