Yet another 8v Digifant Idle Problem...

Discussion in '8-valve' started by Kai, Feb 10, 2009.

  1. RIP-MK3 Forum Addict

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    can coolant temp sensor cause idle issues as mine is goosed I think?
     
  2. 50ftdubdemon Forum Member

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    knackered blue temp sensor is more associated with car not pulling right... but when i pull the plug off the top of mine to set it up it does idle a bit rough so suppose they could be linked but would have to be properly dead to mess up your idle
     
  3. KAI

    Kai Forum Member

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    Well, i unplugged the blue temp sender and the idle was perfectly stable, purred like a kitten!

    It wouldn't rev past about 2000rpm though with it unplugged, so i ordered a new one last week.
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    You diagnosed the problem ages ago, you just didnt know it :lol:

    Remember when you pressed the top throttle switch and the idle settled, then it went all wierd again when you released it? That was a test that confirmed the idle switch is not working, either it isnt adjusted correctly (set it so it clicks when throttle shut) or it or the wiring to the switch is broken.

    Both throttle switches are wired in parallel, the ECU knows the difference between full throttle and idle by checking what the rpm/airflow is at when it sees a closed circuit on the throttle switch plug :)
     
  5. KAI

    Kai Forum Member

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    So its the throttle switches, and not the coolant temp sensor? :)

    The switch assembly is....erm....expensive :(

    Can you re-use the throttle body gasket? I'm guessing not, but, i may take it off anyway to clean it and get a new gasket when i go to VW tomorrow to pick up the CTS for the ABF.
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    is the idle switch definitly clicking? if not, loosen he screws and move it so it clicks just as the throttle closes. if it is clicking ,then fin yourself another pair of throttle switches, or just get hold of another throttle body :)

    I may know someone who has one, I'll ask him tomorrow :thumbup:
     
  7. KAI

    Kai Forum Member

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    The throttle body refuses to come off. one bolt came out, the others are wedged in tight, and one of them has rounded off internally :/

    Still, i should probably take off the rest of the inlet manifold, clean it up and use new fixings anyway, would rule out a vacuum/air leak.
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    you can remove the switches with the tbody still in place, its not easy but it can be done! I havent spoken to my mate yet either, I'll make sure I do so today :lol:
     
  9. KAI

    Kai Forum Member

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    Well, the throttle body is coming off, i'll have to rebuild the top end while i'm at it, far too many bolts are either shearing off, rounding off or just plain won't move :(

    Might be easier to get a complete PB engine....but, i no of no-one that would pallet one to me :S
     
  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah 8v inlets are a sod to remove, so glad i only have 16vs now :lol:
     
  11. KAI

    Kai Forum Member

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    I swear - this thing is going to be a pig to remove, MORE BROKEN BOLTS! GRR!!

    I think the previous owners never maintained it...

    Know anyone with a Digifant fuel rail, by the way?
     
  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    i'll ask me mate!
     
  13. KAI

    Kai Forum Member

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    Thanks muchly, i need one! [:D]
     
  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    he doesnt have one im afraid :(
     
  15. KAI

    Kai Forum Member

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    Bugger :(
     
  16. KAI

    Kai Forum Member

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    Getting one from VW (Fuel Rail, that is), but, i discovered my problem.....the throttle switch for WOT is fine, but the idle one...well...its half missing!

    Anyone got one knocking around, or am i in for a 60 bill? :(
     
  17. rubjonny

    rubjonny Administrator Staff Member Admin

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    is it deffo half missing, there is no big metal spring arm on the idle switcvh if thats what you mean :)
     
  18. Mike_H Forum Addict

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    Sent you a PM about bits.

    When you're trying to take these allen bolts off, having decent quality tools makes a big difference. You need a 3/8 ratchet about a foot long, with allen bit attachments, and a couple of different extensions for stuff like the throttle body, and the inlet manifold.

    Patience and releasing oil helps too, and if all else fails bang a socket over the bolt heads, or use Irwin bolt grippers.
     
  19. Mike_H Forum Addict

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    It might help, at this point, if you post a quick pic of what your throttle switches look like, and how they sit when the throttle is closed.
     
  20. KAI

    Kai Forum Member

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    Aaah - they were already taken off by the time i read this. The idle switch is half missing - as in, the plunger isn't there anymore.

    Using Halfords Professional Tools - i smacked a Torx bit into the rounded allen bolt on the throttle body - took it out with a nice, satisfying crack.
     

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