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Car wont crank??? help please

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3KO4, Apr 16, 2011.

  1. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    Hi, I have a huge issue a mate lent me his spare working alternator but now it wont even turn. I have checked:

    All the fuses on the side of the dash.
    Fuses/plate on the battery
    Earth wiring on under the battery

    still no luck.
    all the dash/instruments work lights work and stereo works. but the engine wont budge. doesn't even try, I the TB is silent at start, mine always makes a bit of noise before ignition.

    please help me out..

    could it be ECU? or clock issue? imobilizer? car lock up like usual..

    how do I reset the imobilizer?
    #1
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  3. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Apr 16, 2011]
    Was it working before you changed the alternator?

    Immo or ECU won't be affected in stopping it cranking anyway
    #2
  4. mike foster
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    mike foster Fossie VCDS Map User

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    [Apr 16, 2011]
    Can you hear a click when you turn the key ? If not, the starter solenoid might be faulty.
    #3
  5. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    eveything was working fine. until yesterday when the garage placed a volatage reader on the battery after that it didn't make any attempts.

    there is no noise at all, I have a feeling its the imobilizer, as I don't hear the TB or the fuel pump. everything else works. I am soooo annoyed.

    can I reset it with the vag com I have?
    #4
  6. beachbuggy
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    beachbuggy Well-Known Member

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    [Apr 16, 2011]
    sure your battery isn't flat?

    Immob works on the ecu and clocks. even if it took the ecu out the car it would still work you plugged it in! Immob would start the car anyway and then cut it out after 2 seconds if it was that!

    "until yesterday when the garage placed a volatage reader on the battery after that it didn't make any attempts."

    if i read this right the garage put a volt meter over the battery and now it wont work? Maybe the shorted the battery, wouldn't suprise me if they've blown it up!
    #5
  7. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    Thanks for all your replies. I have everything else working on the car thats what is puzling me, lights still power up full beam wippers, etc. and i tried to run it direct from a larger batter no luck.

    my question is.. is there any specific wire or relay for the engine to start that I can check..

    what are the two relays for behinde the air box? I know some a3 dont have these... but was wondering if they are meant to be for the engine!
    #6
  8. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    I am thinking it could be the fuel pump relay. as it doesn't prime up like usual. does anyone know which one it is ? I know it's under the dash behind the fuses but don't know the exact one.
    #7
  9. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    Could it be relay 100 for the ignition?
    or relay 409 for the fuel pump?
    #8
  10. S3SYD
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    S3SYD Member

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    [Apr 16, 2011]
    double check your wires mate as the cable runs from your starter motor to the alternator!!!
    check if you are getting a live 12v feed on the starter and check i think the small plug on the starter also when trying to crank the engine over!!!
    #9
  11. S3KO4
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    S3KO4 Member

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    [Apr 16, 2011]
    checked the starter motor wires took the line off and gave it a good clean still no joy. it has to be the relays will update when I find it. I always seems to get issues very uncomon on the 8L !
    #10
  12. S3SYD
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    S3SYD Member

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    [Apr 16, 2011]
    also have you checked the fuses ontop of the battery tray?in that flip up compartment!!
    #11
  13. S3KO4
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    S3KO4 Member

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    [Apr 18, 2011]
    Ok everyone after another long day Sunday. I still have not sorted the issue. I have check all the electrical and including ignition barrel, the issue is power (+) does not reach the starter motor. I managed to crank it direct from the battery and that work ok. but there is no live power from the (+) connection at the starter motor everything else works ok. I took it for a drive and it felt pretty normal.

    My question is: is there a relay for the starter motor? I am guessing it could be relay 167 or 248 but need someone to confirm tried the manual from Welly's but it doesn't specify!
    #12
  14. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Apr 18, 2011]
    There is no relay. Just a wire from the ignition switch directly to the starter motor solenoid, and a big fat live from the battery to the starter.

    Are you saying there is no 12v at the big wire or the small one?

    Follow the small red/black wire from the starter back up the loom, and check for any breaks? Theres one join in this wire, at the "plenum chamber"
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  15. S3KO4
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    S3KO4 Member

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    [Apr 18, 2011]
    Thank you very much, I have tried to look for it from the barrel there are few about 6 of them black and red I know its the top one (thinner) for the ignition, but it goes into the big loom together behind the dash.

    if I fail to find one can I just get another wire rooted to the barrel or would that cause some issues?

    there is (-) connection big one but not (+) small red and black. voltage is 0
    #14
  16. S3KO4
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    S3KO4 Member

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    [Apr 18, 2011]
    So is there a hard switch to reset the car, some cars have them under the bonnet and some under the driver seats!
    #15
  17. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Apr 18, 2011]
    No.

    At the starter motor there are two terminals. One has a large black wire bolted onto it, and the other has a small red/black wire bolted on. The large black wire should be 12v all the time. Small one should go to 12v when you turn the key.

    If you apply 12v to the small wire the engine should crank. You need to find the matching wire at the ignition switch, and check that it goes to 12v when you turn key. If it doesnt the switch is broken.
    #16
  18. S3KO4
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    S3KO4 Member

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    [Apr 18, 2011]
    I checked all that, there is a specific one black/red on top of the barrel that stays off and when I turn to the ignition position there was (+) 12.4v but the power doesn't reach the starter's small connection red/black wire. :(
    #17
  19. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Apr 18, 2011]
    stick a new piece of wire in then :)
    #18
  20. S3KO4
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    S3KO4 Member

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    [Apr 18, 2011]
    Nice one I think I will, but I will take it to auto electrician first see what they think.
    #19
  21. S3SYD
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    S3SYD Member

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    [Apr 19, 2011]
    just a quick one mate u mite have voltage!! but do you have current??
    seen it before on a circuit were there was voltage but no current!!
    #20

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