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  • Charging issues

    Guys,
    I also posted this to the SIG.
    Maybe someone here has some insight.

    For a while I have been having weird charging issues on my silver race car.
    For quite some time the alt light has glowed with the car running.
    The light blue wires were OK, alt light lit with D+ wire grounded - Ign ON.
    Alternator output was ok, always started, always ran, battery always charged.
    I took the alternator to a alternator shop had it tested the guy said it was OK.

    This past weekend at Summit alt light went out, actually all idiot lights went out, alternator stopped charging.
    With ignition ON, I grounded the D+ wire - NO alt light.
    I checked the bulb and it tested ok and lit up on a test outside the car.
    All wires and connections are very good at the light blue wires. Wires look intact and in good shape.

    My car is gutted,,, parking brake removed, parking brake light wire cut and capped.
    I am taking the alternator to be tested again on Tuesday. Maybe it finally died...
    Its a custom lightweight job I did so its not a stock M3 alt (it is a bosch alt though all similar connections).

    My questions:
    1) I know Jose or Jefrem posted on the SIG about some weird interplay between the park brake light and charging system. Could gutting out the parking brake (and its wire) have anything to do with this?

    2) What is the deal with "one wire" alternators you see advertised in race catalogs. Anyone have any experience with these? That skinny little D+ wire seems designed to fail. I'd love to switch to a one wire setup and eliminate that wire if its at all possible.

    Today I pulled the instrument cluster out of the car to check complete continuity to the blue D+ wires.

    Blue exciter wire (D+) tests good for continuity through to the blue instrument cluster plug & the diagnostic connector.

    D+ wire shows battery voltage with ignition in ON position.

    With ignition in ON position I have NO dash idiot lights at all (ABS, Park brake, Batt, etc)
    SI lights DO work.
    All idiot bulbs do work, test good for continuity and light up with 12V.
    SI board batteries show 3.0v

    Alternator is at the alt shop getting a full checkup, I'll hopefully know more about it tomorrow,,, but the lack of the dash idiot lights in ON position is very puzzling.

    Anyone have any suggestions?
    Thanks in advance...
    Jimmy p.
    jimmy p.
    87 E30 M3 Prodrive British Touring Car
    88 E30 M3 Zinnoberot - Street
    88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
    92 E30 M Technic Cabrio - S14 POWERED!
    98 318Ti M44, Base - Morea Green
    04 Ford F350 - V10


  • #2
    had the same issue

    and it turned out that the Alternator had finally died. RIP. Anyway, the weired thing was that at the beginning the (no)-charge light flickerd and then went off and about 2 hrs later my Batt went dead. Almost mad it home but this is a different story. In essence, the D+ wire makes that thing work and the ONLY reason it is a different wire is that you can have that light.... D+ really is what makes the Alt. work. It creates the magnetic field required to make the Alternator work, and yes you could just have one wire from and to the alternator but then you would not be able to turn the D+ off when the car is off and your batt would go by by in no time. Maybe the one wire alt. have something in ther to only turn it on when spinning or so (or use heavy duty magnets which would make them much heavier) but something is required to make that work and that could break as well. There should be no issue to replace the skinny D+ wire with something more durable, but overall i think it is the best and least complicated solution. No, the E-Brake cannot interfere as long as that cut wire is ISOLATED!!! It sounds (from your description) more like a grounding issue somewhere - did you check all those?
    GG

    ...aerodynamics is for people....
    that can't build engines.....

    Comment


    • #3
      edit does not work.....

      well it does but you cant type as slow as i do......

      oh well, here goes the missing part:



      BTW there is an easy test for alternators. 1 Take t out the car, 2nd get a socket for the nut in front and a dewalt drill, 3rd have a battery and a voltmeter, 4th connect your voltmeter to alt case and alt out, 5th spin alternator with drill and connect the batt - to case and batt + to D+ ------CAREFUL DOING THIS AS THE DRILL WILL BE ALMOST STOP!!!!-------- you should measure 14+ volts as soon as you connect D+ , AGAIN watch the forces and use someone to help holding everything in place!!!!

      Of course this is just a basic broken / works test, it can't simulate real use, vibration heat etc but is has saved me a couple of trips to find out if its busted or not!
      GG

      ...aerodynamics is for people....
      that can't build engines.....

      Comment


      • #4
        Thanks G.

        I am going to see today if the alt is dead. Im hoping it is,,, because if it is not,,, then I have a real mystery.
        At this point nothing on the car tests broken,,, but those lights not illuminating at ON position is really puzzling me.
        Cheers
        jimmy p.
        jimmy p.
        87 E30 M3 Prodrive British Touring Car
        88 E30 M3 Zinnoberot - Street
        88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
        92 E30 M Technic Cabrio - S14 POWERED!
        98 318Ti M44, Base - Morea Green
        04 Ford F350 - V10

        Comment


        • #5
          Those symptoms are weird. It almost sounds like 2 seperate problems.
          My guess (which I know you've heard a million times by now) is a grounding problem. I'm sure you've checked the ground strap from the block to the chassis and the battery ground in the trunk. What about the small grounding nut under the dash near the steering column, is that still there?

          This is ineresting, please let us know when you find the gremlin.
          Good luck.

          Comment


          • #6
            Do these cars have a voltage regulator for the instrument panel?
            VW do. it is a small transistor.
            This might be an I/P problem rather than a charging issue.

            If your DVOM reads 13.8 to 14.2 or so while the engine is running, then the charging system is fine.

            I'd check under the fuse/relay panel for wire shorts and chemical corrosion by water.
            Check the fuses first.
            m.

            Comment


            • #7
              Originally posted by Mick
              Those symptoms are weird. It almost sounds like 2 seperate problems.
              <<< I'm sure you've checked the ground strap from the block to the chassis and the battery ground in the trunk. >>>
              Yep,,, all good. I am going to remove clean / scuff and replace all those chassis grounds though just as a PM tonight.

              <<< What about the small grounding nut under the dash near the steering column, is that still there? >>>
              yep again,,, all tight & clean.


              <<< This is ineresting, please let us know when you find the gremlin.
              Good luck. >>>
              I am really hoping the alt guy says,,, yeah its shot. It was always putting out 13.5v before and everything was fine. At Summit it stopped putting out anything so I am hoping it just died and all it needs is a rebuild. I had to limp through the weekend using two alternating batteries (one charging, one running the car) and a booster pack.

              Thanks for the input,,, I'll be double-checking all those grounds.
              Cheers
              jimmy
              jimmy p.
              87 E30 M3 Prodrive British Touring Car
              88 E30 M3 Zinnoberot - Street
              88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
              92 E30 M Technic Cabrio - S14 POWERED!
              98 318Ti M44, Base - Morea Green
              04 Ford F350 - V10

              Comment


              • #8
                Originally posted by Mmark
                Do these cars have a voltage regulator for the instrument panel?
                VW do. it is a small transistor.
                This might be an I/P problem rather than a charging issue.
                Hmmm,,,, I dont think so.
                The only voltage regulator shown on the ETM chargiong page is the internal alternator one.
                I know there is a resistor in parralell to the alt light bulb in case the ALT light blows so 12V still gets to the exciter wire.

                There also looks to be a diode in place between the park brake light and the alt light. Not sure of the interconnect there. I have the charging page out of the ETM as a .jpg, but never have had any luck posting photos here.

                So what are you thinking of a possible I/P problem?

                Thanks
                jimmy
                Last edited by jimmy p.; 09-08-2004, 05:39 AM.
                jimmy p.
                87 E30 M3 Prodrive British Touring Car
                88 E30 M3 Zinnoberot - Street
                88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                92 E30 M Technic Cabrio - S14 POWERED!
                98 318Ti M44, Base - Morea Green
                04 Ford F350 - V10

                Comment


                • #9
                  Ok an Update
                  Just got the alternator tested. Voltage Reg was blown.
                  Replaced the voltage regulator and alt is working well.

                  Installed back in the car,,, now the three dash lights are glowing again while running.
                  Alt is putting out between 13.5 & 14.1 volts.
                  Alt ground is good, checked continuity from alt to chassis, battery to chassis, engine to chassis.
                  Have full continuity from inst. cluster plug to D+ wire terminal at alternator.

                  I cannot figure why this is glowing. Is there a ground point I may be missing since gutting the interior?
                  I'm running out of ideas at this point.
                  I have stared at that ETM pages for hours and am not seeing anything thats missing...
                  Anyone think of any other reason those lights would glow while running?
                  Thanks in advance.
                  jimmy p.
                  jimmy p.
                  87 E30 M3 Prodrive British Touring Car
                  88 E30 M3 Zinnoberot - Street
                  88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                  92 E30 M Technic Cabrio - S14 POWERED!
                  98 318Ti M44, Base - Morea Green
                  04 Ford F350 - V10

                  Comment


                  • #10
                    Diode..

                    Jimmy, Can't say that I have had your exact problem, however, I have had all three lights come on due to alternator reasons.

                    Once I pitched a belt, all three lights immediately came on, but the problem was obviously the alternator as it was not spinning. Likewise, when I first start the car all three lights remain on until I blip the throttle to excite the D+ wire. Seems on cold starts the idle revs are not high enough to excite the alternator, so I have to blip the throttle. A common E30 M3 phenomenon.

                    This brings my curiosity to that diode you had mentioned. Knowing that diodes allow current to only travel one way, I am curious if this diode is shot allowing current to travel both directions thus illuminating your idiot lights through this parking brake diode?

                    Headed up to Watkins in early Oct??

                    Mark M
                    E30 M3 / E46 M3 / E83 X3

                    Comment


                    • #11
                      <<< This brings my curiosity to that diode you had mentioned. Knowing that diodes allow current to only travel one way, I am curious if this diode is shot allowing current to travel both directions thus illuminating your idiot lights through this parking brake diode? >>>

                      Hmmm VERY interesting thought.
                      I wonder if something like that could be it???
                      Good thinking Mark. I wouldn't have a frikin clue how to check it,,, but its a very good thought.


                      <<>>
                      I am leaving for Japan / Indonesia late Sept for a week and a bit. I'll be home Oct 5th. I am going to do the three day PDA at the Glen, then the two day PDA at Pocono. Is that what you were talking about. If so I'm planning on being there.
                      Im also looking to cram anything else I can in between Oct 5th and Oct 22. If you can think of anything let me know...

                      Thanks for the idea.
                      Anyone know how to check a diode,,, or if what Mark proposed is possible?
                      Cheers
                      jimmy p.
                      jimmy p.
                      87 E30 M3 Prodrive British Touring Car
                      88 E30 M3 Zinnoberot - Street
                      88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                      92 E30 M Technic Cabrio - S14 POWERED!
                      98 318Ti M44, Base - Morea Green
                      04 Ford F350 - V10

                      Comment


                      • #12
                        Vw have a small transistor on the back of the I/P to regulate the voltage to the cluster specifically.
                        I'm inclined to think that the I/P circuitry is shorted somewhere.
                        Is it too much trouble to plug in a different I/P? Or have this one tested? Something in the I/P may be obtaining power via the warning lamp circuit.
                        m.

                        Comment


                        • #13
                          I've had the lights glow before when idling or traveling at low rpms, but when the rpms were raised the lights would go away. (This was on E30 325, not an M3)

                          It turned out that one of the alternator mounting bolts was loose and the alternator could wobble a little bit. I tightened the bolt and the problem went away.

                          Comment


                          • #14
                            Hmmm, now ya made me scratch my head. I have tested diodes already when they were not in the circuit by applying voltage to it and determining if it truely only sent current in one direction and insured that it did not allow me to send current in the reverse direction. Think of diodes as a one way street for electrical current.

                            This link should explain the basics of diode operation and offers a test that can be done with a multimeter.

                            Before I went to all that trouble, I think I would be more inclined to start pulling some of the lighbulbs and determine if removing a certain bulb will make all the others turn off. If so, then begin tracing the current flow of that one bulb.

                            Electrical problems are always a PITA!!!

                            Yes, I will be up at the Glen Oct 9th and 10th also with the PDA! See ya there bud!!! Have fun in Asia!!

                            http://home.planet.nl/~heuve345/elec...e/lesson5.html
                            E30 M3 / E46 M3 / E83 X3

                            Comment


                            • #15
                              Originally posted by ///Empowered View Post
                              Likewise, when I first start the car all three lights remain on until I blip the throttle to excite the D+ wire. Seems on cold starts the idle revs are not high enough to excite the alternator, so I have to blip the throttle. A common E30 M3 phenomenon.
                              Is there some way to fix this problem? It's not a big problem but I dont like it.

                              Comment

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