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new day...new problem - idle

Discussion in 'A3/S3 Forum (8L Chassis)' started by steve bain, Jun 14, 2011.

  1. steve bain
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    steve bain Member

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    this happened in my old car and it sorted itself out so i think it is because the ecu has been out and it needs to get into shape again, but thought i'd ask.

    rev engine, under load or not and revs drop to 400rpm, straight up to 900rpm, up and down 2 or 3 times then levels and is fine.

    was fine before ecu out and battery disconnected. Will it learn and sort itself or from limited research i need to do a TB clean and TB allignment?

    any ideas?

    I do not think its the remap. AGU engine.

    Cheers
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  2. Sandip
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    Sandip Well-Known Member

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    Have you unplugged the MAF to see if that makes it idle any better bud
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  3. Welly
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    Welly VX220 SC Driver :)

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    How long has it been doing it?
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  4. steve bain
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    steve bain Member

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    since the ecu has been out and battery disconnected. was fine before. it seems to happen every time battery is disconnected and sorts itself out within a day or so, but hasn't this time. i will try unplugging the maf and see what happens
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  5. Welly
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    Welly VX220 SC Driver :)

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    Which is how long?
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  6. steve bain
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    steve bain Member

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    sorry. disconnected last wednesday, reconnected friday. drove 200miles on motorway and driven to work yesterday (10miles)
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  7. steve bain
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    steve bain Member

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    also, and most likely unrelated. my elec windows are confused and sometimes go the wrong way. Ie i press up and they go down a bit. then be ok again. they seem more delayed than before.
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  8. Welly
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    Welly VX220 SC Driver :)

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    So that's a reasonable time frame. I would start with the obvious such as a TB reset as you said. Normally a good place to start.

    Link here: Ross-Tech: VAG-COM: Throttle Body Alignment
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  9. steve bain
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    steve bain Member

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    ignore the window thing. just needs resetting after disconnecting battery.
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  10. steve bain
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    steve bain Member

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    right. think i have answered this. as i was in a rush i connected battery, jumped in and drove off for 200 mile trip. It seems i should have let it idle for a minute or so first to 'learn' where idle is or do as suggested below:

    'when you connect the batt, you need to put the key in the on position for ~30 seconds (listen to the t-body, when it stops whining, you're all set), then start up the car and it should be fine.'
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  11. Sam_
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    Sam_ Down under

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    I had to do this recently as I disconnected to change the thermostat. You need to let it sit in the 2nd ignition position until the high pitch whining (TB alignment) has finished.

    When I first got mine I had terrible idle but I:
    - Serviced it
    - New MAF/bolt down coils/plugs (and gapped correctly)
    - TB cleaned and aligned

    It now idles perfectly (touch wood!) with the very very occasional dip, only noticeable if you stare at the needle. Obviously not cheap but things to check if the TB alignment fails.
    Last edited: Jun 14, 2011
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  12. steve bain
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    steve bain Member

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    nice one. cheers bud. I have all new plugs, thermostat cts etc etc. I think i just need to allign it but never realised. I'll give it a go and let you know how i get on. I think i will do a TB clean while i'm at it too.
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  13. SunnyB
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    SunnyB Member

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    I had this same issue after getting a remap done on my AGU engine, revs would idle very low and engine cut out a few time when coming to a stop. Tried realigning TB but didn't fix it, cleaned TB and and worked fine since.
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  14. steve bain
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    steve bain Member

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    To tidy this one up for any searchers in the future.

    I did the TBA as described and it got worse again so the obviously does sort itself slowly.

    so decided to clean the TB. lots of cotton buds and carb cleaner later and it runs very smooth and idles perfectly. high at 1100rpm but i assume it will settle. if not i will do the TBA again.

    Thanks for your help.
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  15. Sam_
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    Sam_ Down under

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    It's worth doing a TBA after a throttle clean...
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  16. s3dave
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    s3dave TFSI Hybrid

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    Yes and it should be done....
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