Charging system WEIRDNESS, need advice

[84c10Tony]

Same here a long time ago, it was a ground, ground it and cleaned it, and all the connects, finally worked. another time, I replaced the old (crusty inside) cables, all worked after. Peeled the insulation back and found the odd issue.
Another time, the internal regulator quit regulatin' juice.
Also have cleaned or cut off cable ends, clean up and reattach clamps, voila'.
A simple tester, can show the resistance issue. Sometimes, replacing a ground wire, or simply cleaning connections makes a difference.
Kinda' like my last relationship, serious resistance showed up 2 years after an overhaul and had to let it go.
Like an old engineer mechanic once said; "sometimes, the best way to handle a problem, is to eliminate it."

 

[mtnmankev]

Like an old engineer mechanic once said; "sometimes, the best way to handle a problem, is to eliminate it."

That's exactly my thinking too, if it isn't an easy fix, the truck is going away by ANY MEANS POSSIBLE, I am not going to spend any money on it at this point.

 

[Itali83]

That's exactly my thinking too, if it isn't an easy fix, the truck is going away by ANY MEANS POSSIBLE, I am not going to spend any money on it at this point.

Shop it to Maine. I’ll gladly take a rust free truck with any and all gremlins

 

[mtnmankev]

My one good neighbor came over today and helped me, we did a hydrometer test on the battery, the float was into the red and electrolyte was a tad low, so we added distilled water and ran a battery charger.
We do suspect a battery issue as a contributing factor.
Cleaned all battery connections and grounds, and I increased the engine idle speed a tad.
Replaced the fan belt with a new one that sits a tad higher in the pulley.
Still has the same issue.
Less than 12 volts at idle, rev engine and max out at 13, let engine return to idle, the 13 volts will hang there a minute then drop back down.

 

[Itali83]

Are you by chance using the stock voltmeter to measure this? Or using a volt meter right on the battery?

 

[mtnmankev]

Are you by chance using the stock voltmeter to measure this? Or using a volt meter right on the battery?

Using the in dash factory voltmeter as well as an expensive fluke meter and my trusty radio shack digital meter at the battery and comparing the readings.

 

[Turbo4whl]

The 2 volt drop, usually is one bad diode. You need to separate the wires from both the positive and negative diode heat sink blocks. Check each diode separately. You do not need to remove the diodes from the blocks for testing.

The other issue could be the grounding case of the diode could be corroded. So when you check them, one lead to the diode wire, the other lead to the block.

 

[mtnmankev]

The 2 volt drop, usually is one bad diode. You need to separate the wires from both the positive and negative diode heat sink blocks. Check each diode separately. You do not need to remove the diodes from the blocks for testing.

The other issue could be the grounding case of the diode could be corroded. So when you check them, one lead to the diode wire, the other lead to the block.

The rebuild kit came with brand new diode assembly, but it could be defective.
All metal to metal connections within the alternator were clean and shiny.

 

[mtnmankev]

The results of the test of the rebuilt alternator : Rectifier - FAIL. Diodes - FAIL. Regulator - FAIL.
Now, the big question is if a defective stator or rotor would cause any or all of those readings on the test machine.

 

[SirRobyn0]

The results of the test of the rebuilt alternator : Rectifier - FAIL. Diodes - FAIL. Regulator - FAIL.
Now, the big question is if a defective stator or rotor would cause any or all of those readings on the test machine.

I'm not sure if that is good news or bad, but at least your getting somewhere.

 

[Turbo4whl]

The results of the test of the rebuilt alternator : Rectifier - FAIL. Diodes - FAIL. Regulator - FAIL.
Now, the big question is if a defective stator or rotor would cause any or all of those readings on the test machine.

If you alternator was tested on a machine, whole and not each part separately, then one bad diode could give all those results. The six diodes, 3 positive and 3 negative all make the rectifier assembly. The voltage is not correct because of the diodes, so it lists as a fail.

 

[Turbo4whl]

Back when I was on the electrical bench rebuilding alternators, would start with full disassembly. Each part was tested separately. You would see any failed parts. Then new bearings, brushes, springs, regulator and a trio-diode if had one. Parts were all made in USA back then.

At some point the bearings were no longer made in USA and we had some fail. We discovered that the imported sealed bearings had very little grease. So each new bearing we popped one side seal out and packed it with grease.

To this day, any sealed ball bearing I use, gets opened and checked or filled with grease.

 

[mtnmankev]

Back when I was on the electrical bench rebuilding alternators, would start with full disassembly. Each part was tested separately. You would see any failed parts. Then new bearings, brushes, springs, regulator and a trio-diode if had one. Parts were all made in USA back then.

At some point the bearings were no longer made in USA and we had some fail. We discovered that the imported sealed bearings had very little grease. So each new bearing we popped one side seal out and packed it with grease.

To this day, any sealed ball bearing I use, gets opened and checked or filled with grease.

It's sad but true, "they don't make anything like they used to and hardly anybody puts pride in their work".

 

[idahovette]

"Pride in work"....back when I started wrenching, I tried to make everything I worked on like my Bride was gonna drive it, then after 14 or so years, like my Daughter was gonna drive it, now since about 1999 like my Grandaughter was gonna drive it.........take NO chances!!!!

 

[mtnmankev]

MYSTERY SOLVED: Defective battery.
I had no reason to suspect it could be the cause as I have had absolutely zero problems with it and it has held a charge and done its job flawlessly.
I feel a tad stupid now, expecting something more complicated being the issue.