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Stutter and Stall

Discussion in 'A3/S3 Forum (8L Chassis)' started by t700bes, Jun 27, 2011.

  1. t700bes
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    t700bes New Member

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    We recently bought an Audi A3 1.6 (2001) and its started to show a few small problems, that I hope someone might be able to shed some light on...

    So first thing to notice is there is a whine coming from the cambelt (it has been changed recently but no reciept).. Its in o the garage tommorrow to be redone, and also the water pump, tensioner etc...

    Based on the fact that the tensioner / belt (not sure which) is whining I had a look online, and people were suggesting that the tensioner COULD make the engine cut out as it would be slightly out of time...

    We can't ALWAYS make it stall on tap, but if you put the clutch down it might stall! Equally, the revs sit at 7.5k - 8.5K and hunt.. So I reackon when it stalls it just hunts a bit too low... Could this all be tensioner related?

    Vagcom shows no faults....

    I hope I have listed everything....
    #1
  2. Speedy Steve
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    Speedy Steve Active Member

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    wow your revs sit at 8500 rpm?
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  3. Alex C
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    Alex C Well-Known Member

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    yeah, i think he meant .85K or 850 rpm
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  4. Sandip
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    Sandip Well-Known Member

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    Check all the hoses around the throttle, first thing i would check would be the breather hose from the rocker cover to air inlet.

    The whine may be a seperate issue....
    #4
  5. t700bes
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    t700bes New Member

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    LOL, yeah I mean 8.5k I will check the breather hoses! I cleaned the throttle body, made no difference...
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  6. Alex C
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    Alex C Well-Known Member

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    .85 K
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  7. Syvo
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    Syvo IF IN DOUBT GO FLAT OUT

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    hehe at least you know what he ment :)
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  8. steve bain
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    steve bain Member

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    ha! don't know anything about 1.6's but on the 1.8T a dirty throttle body can cause very rough idle. may be worth a clean. made mine go from 750rpm to 1100rpm and then ecu sorted itself out. but my point is a dirty TB is not so great.

    when was it last services?
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  9. steve bain
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    steve bain Member

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    actually, thinking about it i think its the turbo which makes the tb dirty, so just ignore me. :)
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  10. lucym
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    lucym New Member

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    The throttle body has been cleaned and didn't make a difference :(
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  11. Sandip
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    Sandip Well-Known Member

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    Unplug the MAF and go for a little drive, if it's any better your MAF is dead lol
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  12. t700bes
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    t700bes New Member

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    I'll give that a go later...

    If its not any better, I assume its worth changing the spark plugs? Is there a way to see if a coil has gone? I have Vag-com and on the measuring blocks I went to the misfire recognition on each cylinder part and cylinder 3 / 4 had 1 in sometimes, where=as the other 2 cylinders stayed on 0..

    Does anyone know what that means? It might be correct.. But I would have though a misfire count should ALWAYS be on 0 :)

    http://www.ross-tech.com/vag-com/m_blocks/010-019.html
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  13. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    NA engines are still subject to dodgy MAF's... this can cause these kind of issues as well as vacuum leaks... may not have a turbo but still has a MAF and crappy pipes :)

    Someone at work had a similar stalling issue on his NA 1.8 20v A4... replaced the MAF and was fixed..

    <tuffty/>
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  14. t700bes
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    t700bes New Member

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    I unplugged the MAF, and it was exactly the same, so I THINK the MAF is gone, is there anything else I can do to check.. Its pricey to change, so don't want to buy one and it not to work :(

    Cheers
    Toby
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  15. Alex C
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    Alex C Well-Known Member

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    i thought that indicated that the MAF was fine...?
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  16. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Unplugging the MAF should give a noticable difference to the way the engine runs if the MAF was ok as the ECU runs on its failover maps... on turbo engines this is more noticable than on NA engines of course but in theory if the MAF was fine then the engine should run better but feel less powerful...

    Its not an exact science of course and logging the airflow should give an indication too... problem is MAF sensors do go and if yours hasn't been changed to your knowledge its plausible this is the issue...

    <tuffty/>
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  17. t700bes
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    t700bes New Member

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    I did do some loggining on Vag-Com I'll put this on later... :)
    Last edited: Jul 4, 2011
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  18. Alex C
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    Alex C Well-Known Member

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    thanks.
    I was thinking that if the MAF was dodgy the car would run dodgy and that if you then unplugged the dodgy MAF it would revert to its 'failover' map and would subsequently run better, i.e. not exactly the same?

    So as he says it feels exactly the same... does that mean its not the MAF or is? or if the MAF is dodgy does the map revert to the 'failover' map aswell?
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  19. t700bes
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    t700bes New Member

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    Below is my log from Vag-com. I think I got the measuring blocks we need, but if you need more please let me know..

    http://tobylockyer.com/download/LOG-01-016-002-015.xls

    The things that caught my attention were:

    Cylinder 4 Misfire

    The Mass air flow is reading something, you can see at row 254 when I'm at full throttle the readings do go up, I'm just not sure what they are meant to be...

    Hopefully so one can help.
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  20. t700bes
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    t700bes New Member

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    Can anyone make use of this? Could really do with a hand here :)
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  21. t700bes
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    t700bes New Member

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    Right so here is the list of things that have been changed, and the problem continues:

    Spark plugs
    Leads
    Coilpack
    MAF

    Checked for air leaks, and can't hear any...

    Whats next on the list :(
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  22. Sandip
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    Sandip Well-Known Member

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    Coilpack? 1.6's don't have coilpacks lol

    How is your coolant temp reading on the cluster? I'm thinking it could be the temp sender
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  23. t700bes
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    t700bes New Member

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    It does have a coilpack! Its behind the secondary air pump.

    Turns out its the CO2 sensor that is causing these problems, when its unplugged its fine!

    Problem is getting to it. I'm trying to remove the plastic inlet manifold and have all the front off, but can't seem to get it to come off the back, maybe there is a bolt / screw underneath the manifold that I need to get to from underneath!
    #23

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