Electrical - Alternator Not Charging | Ford Escort Owners Association (FEOA)
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Electrical Alternator Not Charging

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by Intuit, Dec 13, 2015.

  1. Intuit

    Intuit FEOA Member

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    The point of this post, is to aid in quickly identifying why an alternator may not be charging.
    Basically we will test to confirm that the alternator is receiving it's "turn-on" signal.
    Information may be added as posters run into different situations.
    Note, alternator will not charge if the instrument cluster is not active.

    Tools Needed:
    • 1 Volt meter w/ resistance and DC functions (can use 2 volt meters)
    • 3 Small alligator clips
    • 3 Straight-pins (insert at an angle to probe through wire insulation)

    Identify Alternator Connections:
    3-Pin Wire Harness

    • X - Thicker gauge white-green wire (Constant 12v)
    • Y - Thinner gauge white-green wire (no resistance to ground)
    • Z - Thinner gauge white-black wire (0v with ignition off, resistance to ground, switched to 3v w/ ignition on)

    Single Bolt-On Wire
    • Very Thick gauge Black-White wire (Constant 12v)

    1-Pin Wire Harness
    • Thinner gauge white-green wire (responsible for deactivating dash cluster battery light)

    Preparation:

    Using volt-meter, ignition off, identify/confirm the function of each wire; which delivers 12v, 0v, ground. Confirm that there is resistance to ground on the 0v. Do not make assumptions as wiring color/function may vary from year-to-year, manufacturing plant to manufacturing plant.

    Testing for Regulator Turn-On Signal:
    0) For the following, leave the negative probe connected to alternator casing.
    1) Turn the ignition to Run. (no need to start engine)
    2) Wire Z should now read positive voltage. (3v in my case)
    3) Turning the ignition back to Off, should show it switching back to 0v.​

    If the wire does not go positive, then the problem might be somewhere further up in the circuit. A *factory* manual will be required to help identify and pin-down all the possibilities. Haynes/Chilton circuit diagrams are not detailed or precise in this regard.

    With the engine running and monitoring for change at the battery or bolt-on wire, you can manually apply voltage to the Z wire and see whether the alternator will start charging.

    If the wire went positive but still did not charge until you manually applied voltage, the issue could be that the voltage on the turn-on signal isn't high enough to trigger the regulator.

    If your "Z" wire circuit is weak/faulty and require help with the circuit, let us know. I don't have a factory manual, but there are those here that do.



    ===================
    Backstory:

    Pretty much my own fault, but had to have it towed for the first time ever, early last week. ($180 tow.) The reason it's partly my fault, is because I procrastinated and procrastinated on replacing the corroded connector on the single-wire harness for the white-green monitoring wire on the alternator. This meant I was getting the alternator light most of the time.

    Last weekend I got to testing it. I started it up, and it charged a stable 14.3v. Revved the RPMs and it would quit charging. Dropped back down to idle and it charged. I repeated this for a good five minutes before it quit charging altogether. My alternator charging was in effect, intermittent. This means that it passes bench testing at the auto parts stores.

    Alright, picked yet up another alternator and installed it, only to find it wouldn't charge at all. This would make number three since reluctantly turning my OEM in as a "core" part at ~260k. (I'd still be running on it if I hadn't ignored the squealing from the worn-out brushes.)

    These steps helped me determine that the third replacement was D.O.A.. Well, I'm taking it back and will instead, just get a BWD brand regulator assembly, to be inserted in my second replacement. Amazing how I could be on my fourth alternator in ~60k, until you consider the total lack of quality in replacement parts. I'm not interested in a "lifetime" warranty, I'm only interested in quality parts that don't cost me time and more money.
    LariRudi and ShakeZilla19 like this.
  2. Jdeshler

    Jdeshler FEOA Member

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    Sounds like you understand the charging system perfectly! Did you get a chance to get the other brand in?
  3. Intuit

    Intuit FEOA Member

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    https://www.feoa.net/threads/battery-light-not-on-but-no-charge-dead-battery.86144/#post-766745

    His issue is still pending as well.

    My replacement alternators/regulators do not work for any longer than 10-15 minutes. Then they're dead. :dead: The casing quickly gets warm, and it seems to load the engine considerably. (before dying)

    My battery is rated 625 cranking amps. Their tool that we know of, cannot test charging amps, but it's output was metered 683 cranking amps, approximately 9% over rated capacity. So I replaced it just in case. I don't think it made any difference. Alternator seems to be running full-tilt, (full field,) regardless of battery charge state. The 1-pin monitoring wire has 7.6v steady coming off it, even though the battery is fully charged.

    Voltage drop testing on the negative side, from alternator casing to battery negative terminal/post, memory serving, amounts to ~0.419v at higher RPM. This is with all accessories off. It will undoubtedly exceed 0.5v with all accessories on (including headlamps, high-beams). Considering that the positive side will have some voltage drop, the overall drop will exceed the 0.5v maximum by a considerable amount.

    This situation was created by leaving it parked over a sewer for several months. When I popped the hood, it was practically raining under there... water literally dripping from the underside of the hood. So there's a ton of corrosion under the hood that wasn't there before.

    I'll have to verify voltage drop from battery terminal to frame, then from frame to engine. I added an additional engine ground two or three years ago. However the 12 gauge wire runs from one side of the engine bay to the other. (wire is probably too long) If the terminal to frame tests okay, I'll add at least two other (short) engine/alternator to frame wires. If terminal to frame drop-test fails, I'll have to redo the battery cable(s). I'll also drop-test the positive side of the circuit, from alternator bolt-on wire, to battery positive terminal.

    Once I get the voltage drop, down to something reasonable, it should quit blowing regulators/alternators. Will definitely update this post within a week or two if it turns out that this isn't the case. :writing:


    NOTE: Battery output is rated at 0°F. So the 9% over capacity may have been expected given it's age and that the battery was maybe 40-50°F.
    Last edited: Jan 9, 2016
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  4. zzyzzx

    zzyzzx FEOA Member

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    Update us either way! And yes it's pretty obvious to me that you are doing the right thing here. Yes, I used to be an electrical engineer.
  5. Intuit

    Intuit FEOA Member

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    Problem with the alternator running full-field still persists. :coffee: A detailed wiring diagram will be of benefit. Suspect at this point is the 3v reading on the "Z" wire, described at the head of the thread. This wire is zero volt with the ignition off. 3v with the ignition on.

    Got the voltage drop on the negative side down to just millivolts.
    (will post photos)

    Voltage drop on the positive side is a stable .3v.
  6. Intuit

    Intuit FEOA Member

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    Over charging issue is resolved.
    Back to ~14.3v output instead of >15v.

    Added Engine/Alternator to Frame Grounding

    Added Frame to Battery Grounding
    Suspect the issue was resolved with the prior post. I just needed to finish torquing down the added frame-to-battery ground cable. (had previously stripped the drilled hole) Had temporarily removed battery tray and unbolted engine bay fuse box, to inspect harnesses. Again removed and inspected a few fuses, contacts. Nothing found wrong with harnesses, fuses, contacts.

    Notes
    • White with Green stripe (on single harness monitoring wire) has ~7.1v.
    • White with Green stripe (on three harness wire) has ~7.1v.
    • Voltage drop on negative between alternator casing & negative terminal peaks in the millivolt range.
    • Voltage drop on positive between alternator positive output & positive battery terminal peaks .8v with *all* accessories (except engine fan, brake and reverse lights) running. This will be addressed at a later time.
    Basic Wiring Diagram (color/function not a perfect match for my vehicle)
    https://onedrive.live.com/redir?resid=C43F28D3024191B!1471&authkey=!AMQWX7kjGSejwXQ&v=3&ithint=photo,jpg

    Miscellaneous Information
    https://www.youtube.com/watch?v=ODYMH28RniE
    http://www.maxperience.com/en/ford-escort/detail/answer/85218/alternator-keeps-burning-out-part-2
    Last edited: Jan 9, 2016
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  7. zzyzzx

    zzyzzx FEOA Member

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    Was adding a nut to the other side, and using a threaded screw instead of a wood screw an option there?
  8. Intuit

    Intuit FEOA Member

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    Unfortunately this is not an option unless you use a really really long bolt.

    Bought large stainless steel bolts of sufficient hardness. I think they were machine threaded, not self tapping. Drilled an appropriately sized hole... initially and intentionally drilling too small then testing the bolt to see if it would thread. I didn't use a tap. Basically they were intended to be permanent... not something that you could temporarily unbolt and expect it not to strip-out next time around.
  9. Maxwelhse

    Maxwelhse FEOA Member

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    I didn't read all of the links, and I'm not trying to pee in the punch bowl, but you can add a "frame" ground anywhere that is handy on a unibody car. There's no need to re-use the factory location/wiring to reach any specific spot. You can ground a wire to the alternator bracket (which is just a good choice in general) down to anywhere you want and get positive (errr... negative) results. I haven't scoured our cars for locations, but I'd probably go with the low hanging fruit of punching a hole in the firewall under the HVAC box and backing it up with solid washer/lock/nut arrangement so there's no worrying about monkey business from a self-tapper or wood screw. I do fully endorse your choice of SS hardware. It's the only way to go.

    On a long enough time line I'm going to duplicate the alternator setup from my Mustang on to my wagon. 220A of 3G Ford Police Interceptor goodness. When I get around to it I'll come back around and make note of where the good places to ground things are.
  10. Intuit

    Intuit FEOA Member

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    The two spots on the frame were chosen for their vicinity, easy access and were completely new. The OEM grounds were left buried and undisturbed.

    Vicinity, like contact surface area, is something that can't be overlooked.

    The only reason the OEM was able to get away with such a high gauge (super tiny) wire, is because it is an incredibly short run. The bottleneck in most circuits is going to be the connections at either end... where the wire intersects with the terminal and the terminal with the body of metal.

    I already had a 12 gauge wire running from the back of the engine on the passenger side, on over to a spot near the battery negative tie-down; added some years ago. The problem with that is, the wire run was too long.

    When I did the testing and saw the problem, I focused on the bottlenecks... the connections' contact surface area, and wire run length. I intended for it to be overkill.

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