Alternator doesn't initially provide charge.

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  • Nuvo
    S2Forum Possessed
    • Nov 2003
    • 3826

    #1

    Alternator doesn't initially provide charge.

    My car doesn't charge the battery on the turn of the ignition key, only when I give the throttle a quick blip will it start generating voltage. On the very odd occasion it works as expected.

    Can anyone tell me what is likely to be the cause of this? Could it be worn slip rings maybe, the regulator brushes have plenty of life in them.

    Any help appreciated.
    Last edited by Nuvo; 7 December 2015, 12:55.
  • Pirvu Eugen
    S2Forum Extremist
    • Apr 2007
    • 1978
    • Country: Romania

    #2
    Battery light in the cluster is low wattage or the voltage regulator is bad.

    Comment

    • simon20vq
      S2Forum Extremist
      • Dec 2010
      • 1379
      • Country: United Kingdom

      #3
      spray some wd40 on it and then check.

      Comment

      • hunker7
        S2Forum Possessed
        • Mar 2014
        • 3487
        • Home: Latvia Current: United Kingdom

        #4
        Originally posted by Pirvu Eugen
        the voltage regulator is bad.
        '93 Audi 100 Avant - R.I.P
        '92 Audi UrS4 Avant - SOLD
        '93 Audi UrS4 Avant
        '15 Audi A7 quattro 3.0 TDI

        Comment

        • Pauliusb2
          S2Forum Addict
          • Dec 2014
          • 361
          • Country: United Kingdom

          #5
          I have same issue on 3b alternator,when i start the car it charges only 12.22v and after about 10 minutes running it charges 13.8v i changed the brushes and its same so i think we in need of new alternators....

          Comment

          • Error404
            Super Moderator
            • Mar 2007
            • 19789
            • Country: United Kingdom

            #6
            Have you checked the belt tension?
            Panthero Coupé quattro 20vt
            Indigo ABY coupé
            Imola B6 S4 Avant

            Comment

            • gnutz2
              S2Forum Maniac
              • Aug 2006
              • 928
              • Country: England

              #7
              Sounds like the exciter wire (the small m5 stud on the alternator) doesn't have a switched 12v feed when the car is running, they need this to start charging. If they don't have it they only respond when the revs the start to rise.
              The ONLY S2 Golf!
              http://www.s2forum.com/forum/showthread.php?t=19402
              10.42@138mph
              https://m.youtube.com/watch?v=0wnkkOfFpXg

              Comment

              • quattro-nick
                S2Forum Extremist
                • Sep 2012
                • 1746
                • Country: Belgium

                #8
                when i start my car and the engine is running on low idle rpm,the alternator light goes not off
                this is normal because the alternator is running to low rpm but when i give some gas,
                the light goes off immediately
                audi coupe quattro b2 2.2 20vt project (573hp-626nm)
                TWINCHARGED power,zero lag
                AEM W/M injection

                Comment

                • YELL MAN
                  S2Forum Maniac
                  • Dec 2005
                  • 541
                  • Country: Shetland Islands

                  #9
                  Similar problem as mine. Is the voltage reg on the alternator?
                  1994 Indigo Blue S2 coupe
                  1994 80 Avant 1.9 TDI
                  2005 Yamaha Fazer 1000
                  1953 AJS Model 18S

                  Comment

                  • quattro-nick
                    S2Forum Extremist
                    • Sep 2012
                    • 1746
                    • Country: Belgium

                    #10
                    Originally posted by YELL MAN
                    Similar problem as mine. Is the voltage reg on the alternator?
                    yes,with 2 little srews
                    audi coupe quattro b2 2.2 20vt project (573hp-626nm)
                    TWINCHARGED power,zero lag
                    AEM W/M injection

                    Comment

                    • SteveH
                      Super Moderator
                      • Jul 2003
                      • 4460
                      • Country: United Kingdom

                      #11
                      I've always had this on my 3B and it's not the brushes, belt or voltage regulator as they have all been changed. gutz2 is there something to test to prove it could be the exciter wire/voltage? Mine is definately connected to the stud on my alternator. I may have changed the dash bulb though and never checked what the wattage of the bulb!
                      Last edited by SteveH; 7 December 2015, 18:15.
                      91 Modded 3B
                      14 A6 Avant Black Edition

                      Comment

                      • Pirvu Eugen
                        S2Forum Extremist
                        • Apr 2007
                        • 1978
                        • Country: Romania

                        #12
                        Bulb wattage! Has to be minimum 2or 3 watt.... Cant remember right... But more than 1.2 watt as others.
                        Ignition on, between blue wire and ground... Battery voltage. If not, the wire has a bad connection.

                        Comment

                        • Pirvu Eugen
                          S2Forum Extremist
                          • Apr 2007
                          • 1978
                          • Country: Romania

                          #13
                          But from my experience, is the voltage regulator. Oem ones are good, the aftermarket ones not!!

                          Comment

                          • Pauliusb2
                            S2Forum Addict
                            • Dec 2014
                            • 361
                            • Country: United Kingdom

                            #14
                            I changed all regulator with brushes and same sh**,
                            No idea where to look now lol

                            Comment

                            • Nuvo
                              S2Forum Possessed
                              • Nov 2003
                              • 3826

                              #15
                              Thanks everyone for the replies so far.

                              Here are my findings so far.

                              The battery indicator lamp is the correct rating as it has never been changed at any time before or since this problem.

                              The fault persists after trying a spare Bosch voltage regulator.

                              Belt tension is okay, I can twist the belt about a quarter turn or deflect it by about 10mm or so near the middle if I remember well.

                              After disconnecting the blue exciter wire from the M5 stud on the rear of the alternator body I measured battery voltage with the ignition switch in the first position which is what you would expect to see isn't it?

                              Comment

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