Undercharging

Discussion in 'Mustang II' started by Cool Wheels, Oct 14, 2004.

  1. Cool Wheels New Member

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    K. So I'm at 11.65 V and it doesn't change much with the engine running. When the Regulator is by-passed with a running engine I get 14 V...hmmmmm. Seems to say that the alt is working ok.

    I thought "ok, replace the regulator" right??? Wrong :(

    I could really use some help on the wiring. This will probably show how much I don't know about this circuit. Here's my take on it.

    F= FLD(whatever that means?) = ground.
    S=Stat (Alternator- right - but then why do I have only two wires, one to the ignition module and the other to the fuse panel - is this wrong?)
    A=?? Power wire. There is also a black wire to what could be some kind of capacitor. What the heck is going on here? :(

    Does anyone else get a higher voltage when by-passing(maybe 14 to 16V)? If so I wonder if it could be an alternator issue still?
  2. Mstng2 Founding Member

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    ok but is the alt charging at its rated 65 amps? I'd bet the problem is still the alternator. You can also use the 120 Amp alternator, requires a bit of adapting but does work.
  3. Cool Wheels New Member

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    Don't know yet...I'm going to bring it in to be tested this weekend. I don't have anything rated to test over 10 amps. Thx.
  4. Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE!

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    Since you have bypassed the regulator it could be anything.

    I suggest you step back from technology. Go to the library and get a Chiltons or Motor manual.
  5. Stewart Ledford Founding Member

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    FLD stands for FIELD-it is the magnetic field inside your alternator
    STAT stands for STATOR-it is the part of the alternator that turns inside and is powered by the fanbelt.
    A stands for Alternator
    Normal charging voltage is 12.8-13.2 Volts
    Get a wiring diagram, trace your wires from alternator to regulator.
  6. IICrazy taken away

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    I have a wiring diagram that I made of the charging system before I rewired, so I will go did through some paperwork.
  7. Cool Wheels New Member

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    Ahhhhhgh - Dude :drool:

    "Chilton's/Motor"...fair advice. I have a Haynes. Pretty good at the Generalisms 101. But 102 is where I need to be. I'll give those a try...thx
  8. Cool Wheels New Member

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    Found the problem. Bad wiring. My alternator fizzled out on the road a few years back, leaving me stranded in the middle of nowhere during bear season. I had to hitchhike to the nearest hole in the ground to get shop services. I think they messed with my regulator wiring. It's weird that I've been driving like that for so long with no battery problems. Especially in winter. It makes you think of gremlins or something...

    So they had my ignition wires to the reg stator terminal and the stator wire from the alternator was deadended up the harness.

    What's really weird is that I thought I had pretty good charging voltage before and when I would pull the lead off the battery post to see if the car kept running on it's own power, it would. :p
  9. Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE!

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    ??

    I think I speak for everyone when I say

    WTF?!?!?
  10. Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE!

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    I should have taken the opertunity earlier to say to Never, as in never ever, bypass the regulator and run battery voltage to the field.

    Lets say the battery has 11v and a jumper is ran to the field. Lets say the alternator is working and it's putting out 14v. Which is cool, except the alternator field isn't being fed 11v, now it's being fed 14v and it's output is, say, 16 volts, which is fed tot he field and ......

    In pure theory the alternator can bootstrap till voltage is infinite. In reality I don't know how much voltage an alternator can create by being fed back into itself or what voltage the diodes blow out.... And how much voltage is needed before the ignitor box or anything else electrical that's turned on fries. Or the harness burns.

    That's why I wrote in my first post that it could be anything after bypassing the reg. The problem could have been any one thing before bypassing, after bypassing the problem could be everything.


    But it turns it wa wired how?? This is almost funny.
  11. Cool Wheels New Member

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    Read it again. It was wired as I described above...Phreaky phenomenon!? I don't understand how I managed to keep it fired all this time. The only think I can think of is that the regulator was fubar and shorted out possibly. That's why I'm starting to question the integrity of reality and perceptions related there to.

    This is not :bs:

    As for your warning about jumping wires...I guess you can't trust what you read in a manual. Yes if those of you who have one would like to refer to your Haynes, Electrical... Manual. You will find the procedure recommended. There is warning noted about exceeding 16 volts and to limit the time required for the test however.

    Don't ask me. I'm just Stevie Ray Self-Taught who paid for the so-called expert advice received via one manual ($19.95 CAN + sales tax)
  12. Ricky D Founding Member

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    Hi! I just want to share my experience here...I had a charging problem for a while and i finaly found it :D

    When i redid my engine compartement,i painted the engine bay...and that`s when the problem started...If you dont have a good metal to metal conection betwen the body and the regulator,the regulator goes nut :D and your charging system doesn`t function properly ,sometimes charging enough ,somtimes undercharging...:notnice: I was assuming that the screws would be good to ground the box ...I learned in my case the conection was too clean. :mad:

    After making a solid contact betwen the body and the box,everything was perfect.

    I think it`s not something that apply to your situation here but it might help somebody.
  13. Wart I'm Mad as HELL and I'M not Gonna Take it ANYMORE!

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    If you read only one manual it becomes the bible.

    I don't know how many manuals I've worked with that state to never feed unregulated power to the field, I've worked with too many manuals to count.

    Haynes isn't a stellar reference.

    Don't take this personally, this illustrates one of the problems with 'hobbiests', they do something once and it works (or at least hasen't failed yet) so they think it's vallid. I see alot of this in these forums.
  14. kcobra302 Founding Member

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    (Don't take this personally, this illustrates one of the problems with 'hobbiests', they do something once and it works (or at least hasen't failed yet) so they think it's vallid. I see alot of this in these forums)

    i fell into this catagory with my car in the beginning of the summer.

    a problem reoccured that i had before so i spent a lot of time "repairing" the problem the same way i did the first time. still didn't fix the problem. i was almost obsessed that the problem was the carb or fuel system. after rebuilding the carb, trying to tune it, when thru the fuel system and even went as far as to buy a new carb. guess what it was the distributor. made the assumtion it was ok since it was a new rebuilt unit. i did a few half-assed checks and saw the results that "i wanted to see" instead of doing a thorough job just because i had the carb-fuel thing in my head. live and learn

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