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Knocking noise and engine management light

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Mart77, Nov 29, 2013.

  1. Mart77
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    Mart77 Member

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    [Nov 29, 2013]
    Just driving back from the gym and noticed it was starting to judder with a knocking noise then got a little worse then the engine management started to flash, I've managed to get it home and lift the bonnet, the engine seems fine but I noticed the cat (atlest I think it's the cat ) glowing red, I say red it was really dim but the knocking seemed to be coming from that area.

    anyone have any ideas?

    It's a 1.8 turbo 190
    Last edited: Nov 29, 2013
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  3. Mart77
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    Mart77 Member

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    [Nov 29, 2013]
    It's the pipe before the cat, just to the left of the engine that had a dim glow to it
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  4. dualmono21
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    dualmono21 Well-Known Member

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    [Nov 30, 2013]
    cat could have collapsed and be blocked and stopping exhaust gases escaping ... heating up the affected area
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  5. Mart77
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    Mart77 Member

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    [Nov 30, 2013]

    Thanks for the reply :).

    the part that was a dim red colour was the part of the exhaust where the lambda sensor is. I'm guessing it's what you're saying it is to be honest.
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  6. Mart77
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    Mart77 Member

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    [Nov 30, 2013]
    Just searched the catalytic converter and it seems that's its the part that's glowing red :s
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  7. S4_dan
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    S4_dan Fire up the Quattro! VCDS Map User

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    [Nov 30, 2013]
    Does the engine rev freely? This is common on Vectra C's but without the knocking noise. The cat carbons up thus restricting the flow and the engine won't rev past 3k rpm in MOST cases.

    Remove the lambda sensor from the cat area but leave it plugged in to the electrical connector and start the engine and see if the knocking noise stops/revs past 3k rpm (if it struggles).

    Dan
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  8. Mart77
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    Mart77 Member

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    [Nov 30, 2013]
    On tick over you can just about hear the juddering, reving around the 3k mark it sounds raspy and juddering pretty bad then reving past the 5k the juddering and raspy noise seems to clear. The engine management light is not permanently on now.

    thats with the lambda sensor in, I had a little little go at getting the lambda sensor out but it's proper tight and I was freezing my nuts off lol.


    thanks for your help :)
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  9. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Nov 30, 2013]
    probably a coil pack gone causing it to run on 3. The excess unburnt fuel will be the cause of the glowing cat
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  10. Mart77
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    Mart77 Member

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    [Nov 30, 2013]

    Interesting im im hoping we can get the AA round here tomorrow, failing that I've got a diagnostic machine at work with should pin point the fault :)

    thanks for the info :)
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  11. Mart77
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    Mart77 Member

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    [Dec 1, 2013]
    Ok after plugging the car into a launch machine it's flagged up the coil pack.

    after taking a look at the coil pack in question it wasn't fully pushed down and had a bit of oil on it, after cleaning it up and pushed back down correctly the car is now running fine :). Just want to say thanks for all the info :).

    Tomorrow I'll be going back to the Audi specialist where the car had a full service and mot and rear brakes done which cost over £500, and some questions are going to be flagged up :). Let's just say something's didn't add up.
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