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Voltage regulator?

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Selahdoor, Jul 11, 2019.

  1. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Voltage is electrical pressure, if your batteries have a dead cell or two, they will resist charging. Think of this like a 100 gallon air compressor trying to bleed off all its volume through a tiny pinhole, its going to have a lot of airline pressure behind the pinhole as all the air trys to get out versus if it had a gaping hole in the reservoir, not much pressure there. Pressure is resistance to fluid flow in hydraulics, and if you have bad batteries or poor connections, that will resist the electrical flow into the batteries, making more electrical pressure, or voltage. Im not saying this is your complete issue, but I havent seen it mentioned in the thread before, and I think its worth mentioning as I see it cause all kinds of issues in these old trucks.
     
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  2. BeastMaster

    BeastMaster Full Access Member

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    While you're taking everything apart, could you remove the regulator, inspect it for any corrosion, especially around anywhere the regulator ground connects to the alternator frame?

    It's just a possibility, as theoretically, a poor connection there would cause the situation you describe.
     
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  3. Selahdoor

    Selahdoor Supporting Member Supporting Member

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    I'll do that.
     
  4. hacked89

    hacked89 Full Access Member

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    Thanks for the link, it was thorough. Wherever I read max VPC previously seems off. Upper limit of 14.7v makes sense.

    Sent from my SM-G955U using Tapatalk
     
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  5. franklin2

    franklin2 Full Access Member

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    I did a double take on this problem he is having, especially when he grounded the field terminal to full field the alternator to wide open. Usually, on the separate regulator systems you put 12v on the field alternator terminal to full field the alternator.

    After studying it a little bit, it seems the integrated regulator changes things. You do not have access to the same wiring as you do with a system with a separated regulator. You can see in the diagram below of a separate regulator system, one end of the field is internally grounded inside the alternator, so you need a positive voltage on the field terminal of the alternator to send it wide open charge.

    Just posting this in case someone was like me and assumed all the alternator systems are troubleshot the same way, they are not.

    [​IMG]
     
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  6. BeastMaster

    BeastMaster Full Access Member

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    Frank, seems like that was how the generator on grandpa's car was wired.

    Putting current into F got a lot more out of A, providing the motor was running.

    The trick was to get the generator disconnected if the motor wasn't running, lest the battery would discharge through the generator, backwards. And the generator would carry on like it was a motor. Diodes weren't out yet. All done with segmented commutators and brushes.

    And that crazy little box with three relay- like coils in it, that I never understood.

    But Grandpa sure "blessed" it a lot.

    Gotta admit this 3G alternator design is the Pinnacle of design elegance.

    Thanks for posting the diagram...i learned a lot just looking at it. Not as elegant as that 3G design is it?
     
    Last edited: Aug 24, 2019
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  7. Selahdoor

    Selahdoor Supporting Member Supporting Member

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    Took a bunch of pictures. None of them are worth posting. My camera simply will not focus, close up. And every one of these needed that focus, or they are worthless. Well, I tried.


    I took everything apart again. Replaced the brushes. Cleaned the heck out of every surface.

    Got it all back together.

    For about a minute and a half, it acted normal. Stayed at 14.8 for that amount of time.

    Then I revved it up a couple times. And it climbed right back to 15.6. And stayed there.

    Grounded out the "F" contact.... Went up to 18.4 slowly. Didn't jump.


    Came back down to 15.5, and stayed there.

    Still boiling the batteries.




    The combination of a regulator, the slip rings, and these brushes... is a large chunk of the cost of a replacement alternator.

    I don't think I am going to buy the rings and regulator. Probably just going to go ahead and get an alternator.
     
  8. BeastMaster

    BeastMaster Full Access Member

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    I was just looking at Rock Auto and was not all impressed at the price of a standalone regulator.

    Given that, I'd do the same. Just replace the whole assembly. And keep your problem child in the shed as a parts donor.

    You've done far more than your fair share of chasing wild goose on this one.

    I was going to offer you the regulator and brush assembly from the old one I retired when it's main terminal rusted completely through, but the brushes are worn worse than yours, and my regulator appeared fried and would not work on my test bench. Seems all useful I am getting is a frame, some screws, and a pulley.

    It was my intention to replace it's broken connector with a heavy wire pigtail, but looked like it was becoming an exercise in futility.

    All I can come up with now is that A line, measured at the brush screw, which, by wiring, has to be right at battery voltage... But we already have barked up that tree.

    All that's left you are already planning... Change out the whole shebang.

    Well, I certainly give you an A for effort. I would have done the same. I really hate to condemn perfectly good stuff over a minor bad part. But then, it can get like trying to repair a blown filament in a light bulb...when it's so much easier to go get another one.
     
    Last edited: Aug 24, 2019
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  9. Selahdoor

    Selahdoor Supporting Member Supporting Member

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    Ok, had a night of rest.

    Thought about it a bunch.

    Looked at new alternators.

    Just got home a bit ago... Eating lunch first........


    Then, before I buy anything more at all...

    I am going to go out there and take both alternators off.

    First thing I will do is to swap JUST the regulator from the old truck to the new alt, and see what happens. I've gotten the removal/replacement process down to a science. It will take me maybe half an hour get it back on there and tested.

    While I am at it, I will have a look at the slip rings on the old alternator. If those slip rings are in better shape than these, then I will probably crack open both cases and just swap absolutely everything over.

    If I do all that, I will try to take pics, and show progress. My camera is good for the general pics. Just not for pics where you are trying to show the corrosion, etc. It will not focus well enough for that. (Canon Power Shot A570. I think it's just too old. I've tried everything I could, and can't get it to focus on close-ups.)


    Anyway, I'll get to that, later. Just wanted to post this, so that I've made the commitment to get-er-done... :D
     
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  10. BeastMaster

    BeastMaster Full Access Member

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    Now, I am convinced you are just as much of an old coot as me!

    Already looking forward to the latest post on this saga. Sure rootin for ya!
     
    Last edited: Aug 25, 2019
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  11. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    My Kodak 730 Easyshare is the same way. Overall, it still takes really good pictures for technology from at least 2004.
     
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  12. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    Aren't yu just supposed to yell FOCUS YOU FACK!!!!!!

    Seems to work for AvE........ LOL
     
  13. Selahdoor

    Selahdoor Supporting Member Supporting Member

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    Frustration!!!

    All I did was to swap the regulators. The regulator off the other one is not motorcraft but it's all but brand new. Brushes are barely worn, after the few years that I was driving that truck! Slip rings look practically new, as well. Of course.

    One thing changed. Only one thing... The "Wait to start" light came on, and went off when the GPs had cycled! (Mine cycles normally, then clicks for a while.) That light has not worked... EVER, since I got this truck. And I didn't touch the GP controller or wiring yet...


    Everything else... exactly the same.

    Guys, I don't think it's the regulator.



    Ok, here's the plan from this point on...

    I am going to take the alt back out. And I am going to go ahead and swap all the guts. What I will put back on there will be a new alternator, in an old case.



    Next... I am going to go ahead and take the dash all the way apart.

    I want to disconnect the factory gauge. And connect my multimeter in it's place. Just to see what the multimeter tells me from there.


    I am beginning to have a hinky feeling that the real problem is in the wiring somewhere.

    More than that, I am wondering if the root cause is the headlight switch. That sucker is burned. But so far, it has been 'working"........... Or has it? LOL



    Anyway, at least for today, I am going to try to get the alternators gutted and swapped.

    Took some pics. No idea yet how they'll turn out.

    I'll try to keep up with the pics enough to show the progress tonight.
     
  14. The_Josh_Bear

    The_Josh_Bear Full Access Member

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    If the charging voltage was the same between the regulators then my next step would be triple-checking the sense wire for correct battery voltage. It must match it exactly or within just a few mA difference.

    I apologize if you have already confirmed this, I read most of your posts but didn't have time for all of them as you are good with details and I am not always good with time. :D
     
  15. Selahdoor

    Selahdoor Supporting Member Supporting Member

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    Well, I got-er-done. Mostly.

    Took a lot of pics. But most aren't worth posting.



    Here's the two alternators, side by each.
    alts.JPG
    Left is from the new truck, right is from the old. I believe the one on the right is a rebuilt one.


    The back end of them:
    alts2.JPG

    I moved the regulator from the newer alt, to the alt that fits this truck. Got exactly the same results as before. Did some reading and discovered several instances where the same thing happened to others. They were overcharging. They rep[laced the regulators and it stayed the same. They swapped out the entire alternator and the problem was gone.

    So, I decided that it was time to swap the guts.

    The guts of the old alternator from my new truck literally fell apart as I disassembled the alt. Came out in pieces, along with what looked like a couple cubic yards of crud. It's a wonder it wasn't frozen solid with rust and crud.

    The bearings were very difficult to spin by hand.

    The newer one, although obviously rebuilt, slipped apart as easy as you please.

    As I said, most of the pics were so blurry they weren't worth posting. But here is the red-headed stepchild of Frankenstein result...
    alts3.JPG
    alts4.JPG

    I know your next question... Did it work?


    I dunno.


    I stripped out BOTH pulley nuts! Now I have to find replacement pulley nuts.

    Anyone know the stats on those? (Thread size and pitch.) And where I can get a couple of them?
     

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