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Missfiring

Discussion in 'A3/S3/Sportback (8P Chassis)' started by robdf2, Dec 1, 2008.

  1. robdf2
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    robdf2 New Member

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    [Dec 1, 2008]
    Hi Guys,
    I am from seatcupra.net and have a 57 plate Cupra which is near identical to the S3 engine , reason i am posting here is my car suffers from missfiring at idle and when out on the road.
    I have searched through the various VAG forums to see if i could find an answer to this and also see if other people have the same problem.

    Well my car is bogo standard no mods at all , my problem first started at 4,000 miles , and has had exhaust changed , cat twice , new coil packs , plugs and new maf sensor all of which failed to fix the problem.(no injectors yet)

    My car is now on 11,000 miles and has been at my dealership for the last week and i have recieved an update which i thought i would share , hopefully will give u guys another avenue to try with your dealers.

    Basicaly they have found that cylinder No 3 has a very high compression ratio compared to the others , i have asked what would cause this and at the moment all they can tell me is a valve issue , the head is coming off this week and they will know more once its off.

    I dont think that this is a coincidence to the problems that your S3 drivers are having ? thought i read some posts about injectors on Cylinder No3 being changed?

    Any way thought i would let you guys know that its not just the S3 which is suffering this problem i also know of a lot of Edition 30 missfire issues as well.
    I will post back with any updates that i have.


    Cheers

    Rob.
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  3. dc240969
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    dc240969 Member

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    [Dec 1, 2008]
    Nice to read that. Im home tomorrow and will be checking to see if my S3 still has its misfire problem.
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  4. robdf2
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    robdf2 New Member

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    [Dec 9, 2008]
    Hi all , thought i would post an update.

    The car has been at the stealers for 2 weeks and 1 day and today finally had the news that the cylinder head has been removed and the diagnosis.........

    sticky valves.
    so i am having a new cylinder head and cam belt kit fitted in the next couple of days.
    This should be the fix to my car.

    I suggest that this could be a problem that is new and not widely known , it would be worth a mention next time to your dealers if you still have a problem with missfiring on your S3's.

    Hope this helps.


    Rob.
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  5. jamiekip
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    jamiekip Guest

    [Dec 9, 2008]
    Hope it finally fixes it mate - keep us posted
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  6. dc240969
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    dc240969 Member

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    [Dec 10, 2008]
    Eager to find out if this fixes the problem. Might not rear its head straight away though.
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  7. robdf2
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    robdf2 New Member

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    [Dec 20, 2008]
    Phoned the garage yesterday who have informed me my car is back up and running , they are checking for leaks and then running a few more test but should get it back Tuesday just in time for christmas lol.

    I asked the dealer how bad the sticking valve problem was and if there was any other damage evident once the head came off.
    Basicaly he said that once the head came off SEAT asked them to strip the head down and inspect the parts only problem was that the exhaust valve (cylinder 3) had completley seized and they were unable to remove it !
    so pretty much i had only been running on 3 cylinders , but the good news well sort of was no other damage was evident.
    Will post again once my car is back and i have done a few miles.

    Cheers

    Rob.
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  8. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Dec 20, 2008]
    Just one of the exhaust valves or both?

    I'm not pointing the finger at you or anything I'm just wondering but how hard did you run the car in?
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  9. robdf2
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    robdf2 New Member

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    [Dec 20, 2008]
    Well i got the car with 4k ( was the sales managers car) and tbh i have taken it quite easy , im not really a thrashing sort of guy.

    only 1 as far as i know tbh it was a quick question i asked him and he didnt sound comfortable telling me , but i will ask more when i go to pick my car up.

    i wouldnt have thought that the runing in of a car would have a bearing on valves? especially not just attached to 1 valve?
    thought they were all connected by cam shat , rockers and tappetts?
    might be wrong.
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  10. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Dec 20, 2008]
    It could have an affect perhaps if it was ragged from day one, but that would affect all the valves yes. It's a bit of a weird one I was just interested.

    They're not actually connected to the cam shaft. They're seated in the top of the cylinder and the cam on the cam shaft pushes it down. On an overhead cam of course.
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