78 charging problem

Discussion in 'Ranchero Tech Help' started by Mick13, Mar 24, 2020.

  1. Mick13

    Mick13 In Second Gear

    Messages:
    75
    Hello

    I've got a charging problem :
    I've got the voltage but I presume not amperes
    One wire missing

    on alternator side I've got 4 wires (Ok I'm going to trash the connector)

    [​IMG]

    on the other side, wires goes to the car (with ammeter)
    I've got only 2 wires ! a yellow and a red !
    You see one missing with the red duct tape ... I think it lost from the red connector
    The rectifier only have 3 wires plugged. for my understanding one is missing ?

    As I undestand an alternator 3 gauges use for one revolution 120° of 14V or more, an other 120° circle of 14 and the third the same.
    The rectifier stop that to 14V all that and transforme this alternative in continuous.
    Yelow wire are the 3 gauges (phases in French) if I lost one ore more gauge I've got right volt but not power (Amperes). I presume and I'm sure this is my problem

    Some other pics

    [​IMG]

    [​IMG]

    So I need to know how to wire alternator to rectifier
    How work the excitement on alternator (blue wire on Volkswagen)
    Usually with alternator idiot light, this light do the work to give or not charge to batterie
    positive after car switch on to 12V3W lamp // lamp to alternator blue wire (excitation)
    So no charge light is on + and -
    When charge occurs blue wire become positive so lamp have to positive no earth or - so it can't switch on
    It seems with ammeter, lamp is switched by a resistor ?
    My ammeter doesn't work. So can I switch it for a 12V3W bulb ?

    sorry for my poor English but I read better than I write

    All information are welcomed ;-)

    Thanks in advance
     
  2. Mick13

    Mick13 In Second Gear

    Messages:
    75
    So my rectifier left to right. I - A - S - F

    [​IMG]

    I and F are non connected or plugged
    If I understood well : terminal "I" is a positive after ignition are switched ON, and nothing when ignition is switched OFF ?
    "F" is white wire coming from alternator ?

    ----------------------

    On a forum I've found that

    Depends on if you have a ammeter or a battery light.

    Ammeter-
    I-Unused
    A-hot to battery
    F-field on alternator
    s-to ammeter and battery terminal on alternator via ignition switch

    light-
    I-to indicator light/alternator battery terminal
    A-battery hot
    S-stator on alternator
    F-field on alternator

    And if you have a carburetor, the signal to the elctric choke comes off of the stator signal at the alternator.
    -------------------------

    So I'm confused

    I've got 4 wires coming from the alternator side
    2 going to the rectifier (and one unplugged )

    I don't care about ammeter, so if a simple lamp is better that's ok for me

    So please explain me what to do and what is what as I love to understand what I do ;-).

    Thanks
     
  3. burninbush

    burninbush In Maximum Overdrive

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    Hi Mick13 ... not clear about your problem? It is not possible to have a correct voltage measurement and not enough current to zap the battery. If you measure 14 + volts at the battery with motor running, that is evidence that it is charging. If you only measure 12 + volts, then it is not charging. You didn't mention starting problems, so I doubt that's the issue.

    It seems that you want to have the indicator light working? I suggest that you change that regulator for a modern version, and then look on the web for a Ford alternator connection. A '70 manual has it, very simple, two different diagrams for amp gauge and charge light.

    Try this ... http://carsut.com/wp-content/uploads/2015/12/ford-alternator-wiring-schematic.jpg

    You might find it simpler (and more useful) to put a voltmeter gauge on it instead of a trouble light
     
  4. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    The "red" connector, I would swear, looks to be test adapters for an automotive scope. They certainly do not belong. I would say, right off the bat, you need a replacement harness just to remove the splice connectors. As for a diode problem (which causes you to lose a phase/gauge), a simple test: wait till night, then start the car, and turn on the parking lights (but not the headlights). if a diode is bad the bulb's brightness will waver (go alternately bright and dim quickly). If that's the case, you need an alternator or to rebuild this alternator, with a new diode bridge. The only other way to see if the diode bridge is bad is with an oscilloscope.
     
  5. Mick13

    Mick13 In Second Gear

    Messages:
    75
    the problem is that I've to charge the battery frequently. I've got a booster behind driver seat ;-(
    when I check voltage on battery, engine switched off, I read something around 12V. Engine running, something around 13 or 14v, I don't remember exactly.
    I suspect voltage Ok but amperes not.

    I don't care about light or ammeter. But about the light with European car, I know that no working light is no charge. That's why I look about this light.
    The Ranch have a non working ammeter gauge.
    I like the voltmeter gauge I've had that on my VW MK1, Volvo etc

    I will replace most off the wires and trash the red connector.

    Andy I will try your method next night.
     
  6. burninbush

    burninbush In Maximum Overdrive

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    Suggests a bad alternator to me, probably missing a diode or two.

    My reference to 'can't be' above is due to the extremely low impedance of the battery; if it shows more voltage when it's running then it =must= be charging.

    Here's the Ford drawing from the manual ...
     

    Attached Files:

  7. Mick13

    Mick13 In Second Gear

    Messages:
    75
    i've to real check all that. If the alternator is shot, maybe I'll do brackets for a Volvo one !
     
  8. 72GTVA

    72GTVA Administrator Staff Member

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    How old is the battery?
     
  9. aquartlow

    aquartlow In Maximum Overdrive

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    I'd go with a large case 130 amp 3G, just sayin'.
     
  10. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    If you charge the battery, you should show 12.65 or better for a full charge. If you're showing just under 12 volts, it has a dead cell, which drains off the battery. You need to disconnect the negative cable, charge it, let it rest 15 minutes for the voltage to stabilize, record exact voltage, if it's around 12.65V, then let it sit unconnected overnight, and recheck the voltage. a loss of more the .03V in a half day shows discharging.
     
  11. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    "Go big or go home," huh? You'll make him an American, yet!
     
  12. Mick13

    Mick13 In Second Gear

    Messages:
    75
    Yeeeepeee
    I've found the problem. bad ground unconnected wire etc !!!

    ignition off (batterie charged at home)

    [​IMG]

    engine running lowest voltage.

    [​IMG]

    And now, engine running

    [​IMG]

    [​IMG]
     
  13. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Sorry, I don't read or speak French, but I do understand testers with colored lights, and it is your alternator, so I know you mentioned using a Bosch unit, if you can get an integral regulator alternator, it would simplify your wiring. You should also consider a fresh charging cable with new ends.
     
  14. Mick13

    Mick13 In Second Gear

    Messages:
    75
    Andy, I've stay with the Ford alternator and rectifier. the charge is at 14,29V so it's Ok. The small tester in fact is jus a volt meter. It state : motor running, charge is between 13?2 and 14,5V. I've use it just as a double check.
     
  15. Mick13

    Mick13 In Second Gear

    Messages:
    75
    for my knowledge : can you tel me what wire is for what on alternator ? I see no letter to indicate
    I presume big red with bolt is for direct to batterie ?
    But the other 2 ?

    [​IMG]
     
  16. Mick13

    Mick13 In Second Gear

    Messages:
    75
    I agree that for engines ;-)
     

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