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Possible alternator issues

Discussion in 'A3/S3 Forum (8L Chassis)' started by Westy, Jul 22, 2013.

  1. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Hi guys. New week and a new problem.

    Car has been getting progressively sluggish on start up and today the battery low voltage symbol appeared on the dash. I fitted a brand new battery around 6 months ago after I had start up issues in the cold. I'm now starting to think the alternator is on its last legs.

    Can anyone tell me what the best tests are to do to determine whether I have an alternator issue? I'm picking up a voltmeter today for some basic output diagnosis.
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  2. BENJAMIN
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    BENJAMIN Member

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    Just test it's voltage output. Also remove the battery tray and ensure the earth connection to the body is corrosion free, happens a lot on tt's!
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  3. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Thanks Ben. I ha the tray out not to long ago and seem to remember the earth looking ok but I'll check it this evening.
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  4. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Just had the call from the mrs. Car is totally dead. She's calling the RAC to get her home. Hopefully the guy will troubleshoot the alternator for me before he jumps it.
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  5. Lewis583
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    Lewis583 Active Member

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    If they don't. Then put you voltmeter on the battery with engine running with no load (minimum electrical circuits running, radio,heater etc) it should read approx 14-14.4 volts.

    Then switch all electrical accessories on; heated window, radio, heaters, lights etc; and retest. It should not read less than 13volts. If it does the alternator is scrap.
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  6. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    TBH new batteries fail. I'd bet you have a small drain somewhere and it's pulling the battery down. Has it been left to go dead flat at any time?
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  7. s3dave
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    s3dave TFSI Hybrid

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    Just Keep Calm Fred and keep away from cliffs....;)
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  8. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Its never been left to drain flat but I'm wondering whether my WMI kit or Devils Own solenoid is draining it! I hope I don't need another betters already, they ain't cheap!
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  9. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    It'd be under warrenty anyway surely...

    I had my Bosch S4 one go down within a few mnths, it's replacement has been perfect
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  10. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Well what a journey home. RAC are total poo and took so long that I went and rescued the girlfriend myself. Jumped with leads and battery symbol constantly illuminated on the dis. On the way home I start to spot problem after problem!

    Firstly, a slight knocking/wobble through the steering wheel. GF assures me it on started doing it today.

    Secondly the brakes start squeeking at low speeds when rolling and of the brake pedal. I give the handbrake a pull and it does nothing. I'm guessing sticky rear calliper.

    Thirdly, while we're on the subject of brakes, the fronts are creaking when pressing the brakes. No idea what this is. Possible the anti vibration shims I put in when I changed the pads recently.

    Fourthly, car starts to idle and run like ****e. Feels like a coil pack going but I suspect it's the injector fault I had last month.

    And lastly! ABS light keeps coming up and disappearing on the dash.

    Looks like I'll be having a fun evening of fault finding!
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  11. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    if it wasn't charging it'd throw all sorts of errors. Given the warning stayed active it was either dead shorted battery casuing it to draw oodles of current, and the alt just kept up to keep car running. Unless you left jump battery connected on drive home?

    Or non charging alt, however, given you drove it home, that may not be it, test it
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  12. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Yeah that particular issue looks to be the battery. I'll test for something draining it. Just found the receipt from 24th feb this year so should be able to swap it under warranty.
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  13. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Ok, I wanted to do some poking around before I tested the volts with te engine on. Stripped out the battery which currently reads 11.18 volts and wanted to look at the earths under the tray.

    [​IMG]

    The only thing I've really fitted recently is the Devil Own solenoid to prevent WMI syphoning (the red spade connector). I can't believe this would cause drain as it is only active when te ignition is on. 1 wire goes to the in car ignition feed in the drivers footwell and then this wire I put here. Can anyone tell me whether these connectors under the battery tray are anything other then earths?

    Few more pics of their condition:

    [​IMG]

    [​IMG]

    [​IMG]
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  14. S3Zek
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    S3Zek Member

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    good scrub up wouldn't go a miss at the points and the ring ends by the looks of it, I would do the earths to the block and the starter while your at it.
    but from what your saying I would change the alternator if its not putting out around 13 or over when loaded up
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  15. S3Zek
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    S3Zek Member

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    i did all mine when i had that fan fault
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  16. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I've not checked the alternator just yet that's tomorrows job after I've worked out whether I have something draining the battery first.

    Found this video on another thread, perfect:

    youtube video
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  17. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Just jumped the car and with it running was only seeing 11.5 volts across the battery. This was with nothing electrical running. I forgot to turn everything on and I now have the car in my garage and no jumper car available at the moment. Does this sound like a crappy alternator or what!
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  18. Sam_
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    Sam_ Down under

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    Does sound that way. I was always told 13.5-14.5 volts when I was at college. More is actually more of a problem than too little! A frying battery makes a horrid smell. Probably doesn't help the other electrics on modern cars.
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  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    The battery appears unable to charge at all. Has voltage of 11.17 on its own which isn't enough juice to even turn it over. With the car running it was 11.5 which isn't going to charge a dildo!

    Just checked for amp draw and I have 30 m amps (guy in vid says anything over 50ma is bad). I think I'm reading it correctly as if I turn on the interior lights I see 210ma. My tests might not be the best as I have a shoddy battery. I'm heading to halfords later to try and swap the battery under warranty then I can retest.

    Looks like I'll need a new alternator then! Any recommendations? Also any other alternator health checks I can do? I'm not sure which earth strap Ben meant above but the ones I've seen all look within reason.
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  20. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    the battery is shorting it out. Especially as its running after a jump as obviously that means its charging but the battery is shorting the output and not accepting a charge
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  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Please explain in layman's terms as I'm bad enough with electrics let alone auto alectrics! What can I check? What should be my next steps of diagnosis or is it a case of new alternator and battery?
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  22. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Just jacked the rear up and spun the wheels both sides. Perfectly fine, 3 rotations both sides when I spin as hard as I can. Now need my jumper to come home so I can turn the car round in the garage to investigate the fronts and also whip the alternator off. Think I'll just get a new one and new battery at the same time and that should sort it out.
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  23. Westy
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    Westy Double Dark Side! Diesel & 8P

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    How on earth do you get these alternators out!

    This is my engine bay at the mo:

    [​IMG]

    As you can see I've got the 2 bolts out I just can't get the bottom bit off the bracket and there's not much room to use anything to lever it off.

    [​IMG]

    [​IMG]
    #23
  24. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Got it! Went chuck Norris with the rubber mallet and a big screw driver.

    [​IMG]

    [​IMG]
    #24
  25. Vex182
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    Vex182 Guess what I drive...

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    Mine failed on me last year on the M1, car just died at 70mph and I lost everything. AA picked me up and I changed the alternator, drive belt, quick jump start and all has been well since.
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  26. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I think this is the original alternator so has done 144k miles! As my battery is still under warranty I'll try and get a new one and then it'll all be new ;)
    #26
  27. Vex182
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    Vex182 Guess what I drive...

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    Thats done well then, mine failed at 99k.
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  28. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Just started her up and went for a drive. Feels like a brand new car! Throttle response and idle was brilliant, so I think the alternator has been struggling for a while. I'm now getting 14.5v across the battery with the car on. Bit better then 11.5v!
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  29. g60leigh
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    g60leigh Active Member

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    Good stuff mate.
    Was alternator turning freely when you pulled it or giving resistance?


    Sent from my iPhone using Tapatalk 2
    #29
  30. superkarl
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    superkarl MAN OF STEEL

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    Your old one with such a low output couldve been the cause of your injector fault you were having.
    Just a thought.
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  31. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I didn't check that mate. It just wasn't generatin enough juice to do anything. I've also sorted my sticking front brakes so all I need to sort now is my intermittent brake light switch issue and a sticking door switch which is causing the interior lights to go mad! The heat seems to be playing havoc with the electrics more then the cold does!
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  32. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I think it was definitely the cause of the cam position issue. It turned over for a bit and spluttered where the position must have been slightly out but when it started it smoothed out and felt great to drive. Scanned the car before and after a 15 mile run and it's all clear.
    #32

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