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Voltage regulator?

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  • Jeffrey S.
    Extremely Frequent Poster
    • May 31, 1988
    • 1882

    Voltage regulator?

    hello All,
    I have a new issue on my '69 that just developed. I started the car for the first time since last fall yesterday. Previously, whenever I started the car the, the ammeter would go way left on cranking and then as soon as it started would go way right and then move to the center. Now, cranking goes left and at start the needle goes halfway to the center and stops. It did, after a few seconds, rebound and go to the right as before and then act normal. Voltage when running is 14+ volts and 12+ volts when off. Could this be indicative of a failing voltage regulator. This is the original alternator that was rebuilt many years ago. As always, thanks for your help.
    Jeff
  • David M.
    Very Frequent User
    • September 30, 2004
    • 520

    #2
    Re: Voltage regulator?

    14+ VDC running is good. 14.2 is optimal. It should be steady not bouncing around.
    What's the battery surface voltage after it sits for a day? 12.6 VDC ish is a good battery.

    Load test the battery. Does it pass or fail? Schumacher and others makes the better load testers Don't be fooled by the junk at harborjunk. It looks the same but it isnt.

    If the battery is failing it will take longer for the ammeter(alternator/charge circuit) to recover and provide a full recharge. Bad connections will cause this too. A Full system recharge can take 10-20 minutes of road time to equalize from just one start. Bad connections make everything work harder especially when hot.

    Routine battery and start circuit service is vital to any car older than 5 years.

    Clean all positive and negative grounds. Ohm Test the large secondary battery cables. Are they original? If yes chances are they are ready to be refreshed. The Neg cable from the battery to frame, under the seat, needs to be clean where it connects to the frame.
    The positive cable needs to be clean on both ends.

    After cleaning using a brush and battery cleaner always follow with the terminal protectant spray. Do this on anything you cleaned. It will seal it. This is an annual requirement.
    Make sure the ground from the engine block to the frame on the passenger side is in good shape with a good connection. Its likely petrified.

    Lastly the starter and solenoid should be serviced before failure. Resistance builds as the brushes wear. Dirt/carbon builds up on the armature end. The grease drys out. The drive assembly dries out. The solenoid disc and connections on the sol cap get dirty and cause increased resistance et al... you get the point.

    Start simple with the battery and connections.
    Attached Files

    Comment

    • Jeffrey S.
      Extremely Frequent Poster
      • May 31, 1988
      • 1882

      #3
      Re: Voltage regulator?

      David,
      Thank you for the very detailed response! I appreciate the time you took to help. Let me supply more details. First, the battery is brand new. The old one failed as I was at the pump at Costco and I had to be towed. Fortunately, I was a half mile away from Werner Meier's shop so he took care of putting in a new battery and going through many of the things you suggest. I will clean and the connections (I also have a green knob battery disconnect also new). The ammeter needle stops dead at halfway between full left and 12 o'clock on cranking and then after a few seconds snaps over to full right and then moves to center. When it happened I jumped out of the car and wiggled the wires connected to the VR and got back in the car and the needle was where it belonged.
      I will check each of the items you suggest as soon as I can. I have seen Delco NOS VR's on eBay for very reasonable prices so maybe I will also just replace mine after doing the checking/cleaning.
      Jeff

      Comment

      • Patrick H.
        Beyond Control Poster
        • December 1, 1989
        • 11643

        #4
        Re: Voltage regulator?

        Try starting the car without the green connector and see if the issue is present.
        I am not a fan of those, and have seen my fair share of issues with them with regard to starting, resistance, etc.

        I only use the Savety-Switch ones (knifeblade style) now.

        PH
        Vice-Chairman (West), Michigan Chapter NCRS
        71 "deer modified" coupe
        72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
        2008 coupe
        Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.

        Comment

        • David M.
          Very Frequent User
          • September 30, 2004
          • 520

          #5
          Re: Voltage regulator?

          Agreed about the battery disconnect.

          A new battery can fail. Thus the handy load tester.

          But first see what the voltage is doing when the meter is flaking out. Is the VDC steady and climbing to full alternator output ~14.2 VDC?
          A second known good inline amp meter would be nice to have to physically see the amperage.

          Don't install any parts until this is diagnosed. You risk damaging the part or wasting time & money.
          Could be a few things causing this. Bad connections, Bad meter, bad VR, failing bridge diode pack in the alt(new or recently rebuilt can still be bad out of the box).

          Check the connector at the VR. It and the spade connectors can deteriorate. Oxidation can hide there so inspect.
          That connector with pig tail wires is available and can be properly spliced into the harness(solder & shrink tubing only no crimp style solder-less connectors).

          The ammeter in our 68 is flaking out. It bounces erratically between 1-1500 RPMs. I did have a bad diode in the alternator. That was rebuilt last year. But it didn't fix the flutter. Only thing left is the ammeter. That will be repaired/replaced this season.

          There are 2 grades of the green battery disconnect. The $5 and the $20 version. I like the green knob style as it can be completely unscrewed and removed from the car. Added theft deterrent. I remove it at shows. Wont stop a determined thief but it will slow them down.

          I will be traveling on business this week if my response is slow.

          Comment

          • Jeffrey S.
            Extremely Frequent Poster
            • May 31, 1988
            • 1882

            #6
            Re: Voltage regulator?

            Patrick- I will try without the disconnect. I know many people don't like these but I have been using them for many years and have never had any problem with them except when they completely fail and then I just replace.

            David- I will try all of the things you recommend before replacing anything. I am guilty as charged with using the cheap version. I have about a half a dozen on hand, some with a small 1/2 amp fuse that allows the clock to keep running but will blow if even the brake lights go on.

            Thanks again for the help.
            Jeff

            Comment

            • Jeffrey S.
              Extremely Frequent Poster
              • May 31, 1988
              • 1882

              #7
              Re: Voltage regulator?

              Update: This morning I started to go through all the suggestions made by Patrick and David. The first thing I wanted to do was to eliminate the cut off switch. I found that the connection between the switch and the battery was very loose. I tightened it up and started the car. Everything worked as it had for the last 50 years! The needle went right to the right and backed off as the car ran. Problem solved? I hope. Thanks for your help.
              Jeff

              Comment

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