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Audi A3 1.8T misfire

Discussion in 'A3/S3 Forum (8L Chassis)' started by steve bain, Jan 28, 2013.

  1. steve bain
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    steve bain Member

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    [Jan 28, 2013]
    Morning all.

    I am looking for some guidance. I have a 1.8T AGU. Last night it was driving fine with no problems what so ever and hass been fine for a while now. This morning jumped in (after a very heavy nights rain if that makes a difference) and it appears to be running on 3 cylinders. It idled a bit lumpy and on pulling away just felt like it was on 3 cylinder, pop, pop, pop, and very very little power.

    I was on my way to work so pulled over and unplugged all the coil packs, gave them a blow and plugged them back in with no difference at all. Didn't think it would, but can but try.

    I'm at work so have no chance to look today and will call out the rac later to get home (and hopefully they will diagnose or fix it) but if not I will have to.

    First thoughts are to run the car and unplug each coil pack in turn to see which one is not sparking due to change in engine sound. When i see which one it is, check spark plug and I guess replace coil pack? Although I thought the coil packs on the AGU were pretty sturdy? Other then that i guess wiring? maybe rubbed through somewhere?

    Just seems odd it would happen over night if it was a wiring issue.

    I will also plug it into the VCDS-lite when I get home.

    Any ideas?

    Steve
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  3. steve bain
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    steve bain Member

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    [Jan 28, 2013]
    should add it makes no difference with hot or cold engine, boost is normal and is worse when accelerating, but is there all the time. A bit more reading up shows that the loom can rub on the cam cover.... any thoughts?

    Steve
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  4. s3dave
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    s3dave TFSI Hybrid Supporter

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    [Jan 28, 2013]
    Do you have the IGN Amplifier? these can cause this..
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  5. steve bain
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    steve bain Member

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    [Jan 28, 2013]
    thanks for responding. I have a feeling i do. I also have a horrible feeling its the bit that dangles in loose air and has black tape all over it. I have always wondered what it was but it has not proved a problem yet. I think I may have a poke around at lunchtime
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  6. steve bain
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    steve bain Member

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    [Jan 28, 2013]
    more research is showing that the ignition module is a very strong contender. Thanks for pointing me in that direction, very much appreciate it.
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  7. steve bain
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    steve bain Member

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    [Jan 28, 2013]
    Right, i had a play tonight and cylinder 1 is not sparking ( drivers side). My laptop is dead so no vcds i'm afraid. Either way cylinder 1 produces no spark. I swapped the coilpacks and it is still cylinder 1. So not coilpacks or spark plug. Heres the odd bit. The supply lead to the coilpack hows the same reading on all 4 cylinders! Does this mean it cant be the ignition amplifier? I gave that a clean up too which made no difference eithet. I tried wiggling wires with engine running also no difference so assume its not a break in the wires. Its thr same readings on the cables which confused me. Any ideas? Apologies if the message reads badly but i'm writting on my phone!
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  8. 16Klappe
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    16Klappe RacecaR forward is RacecaR backwards. Supporter

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    [Jan 28, 2013]
    I'd try for either cracks in the coil pack wiring, or an injector fault.
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  9. Prawn
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    Prawn My other car is a MINI!!!!

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    [Jan 29, 2013]
    as above, it's very unusual for AGU coilpacks to go down.

    Ignition amps can work in very strange ways though, and can often cause just one or two cylinders to drop out.

    I'd be checking the coilpack wiring, it gets pretty brittle in there, and if you're able to swap out the ignition with a mate to test I'd do that as well before buying another.

    You said above you swapped coilpacks over to #2, did you check the plugs as well? as it could still be a dead plug.
    #8

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