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normal idle speed and feel in your S4?

Aspen Aug 10, 2018 at 9:48 PM

  1. Aspen

    Aspen Member VCDS Map User

    Hi Guys,

    Im slowly getting round the car, you know, getting it all to my liking. a wheel alignment, all wheels balanced full clean inside and out. You know the usual.

    But before I go fitting the 6 new coil packs in the morning, can you tell me if this is normal please.

    My S4 idles at about 650 rpm, it seems very low. And feels 'lumpy' on tick over because of it. almost like my old V8 S5.

    What else could this be, or is this just a class effect?

    80k on the clock and been driven by miss daisy all its life.... Well, until now I suppose. lol
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  3. Aspen

    Aspen Member VCDS Map User

    Could this be a vacuum leak?
    Where to start I wonder.
  4. RyanJonS4

    RyanJonS4 Drive It Like You Stole It

    They do idle very low and can be a little lumpy.

    The factory crank pully has a rubber damping section in the middle and these have been known to fail and cause a fair bit of damage. That would be my first check.

    If the car has been driven by miss daisy, it doesn’t do them any good at all and can cause the old carbon build up around the valves to happen a fair bit faster. This is impossible to investigate without taking the supercharger off though.
    Tashfeen likes this.
  5. Aspen

    Aspen Member VCDS Map User


    I stripped down and replaced the air filter. It was a bit dirty tbh. And had a good check of all intake attachments for tightness and all vacuum lines.

    I then blasted the throttle body valve with cleaner and cleaned that right up as this made a huge difference to my 997. Stuck an inspection camera inside to see if there’s any bios up or oil residue. It looks pretty clean.

    The blasted some cleaner through the chamber whilst running the engine, well, just because and then refitted everything making sure it’s all nice and tight.

    Then I checked all the coil packs and refitted them.

    Weirdly. Huge improvement! Almost as big an improvement as with the 997. Maybe they’re just as sensitive?
    Roadrunner146 likes this.
  6. scotty76

    scotty76 Well-Known Member Team Phantom Audi S4

    Bit late now but mine idles at 700rpm and has always felt lumpy.
    Tashfeen likes this.
  7. Tashfeen

    Tashfeen S4 - the smile per mile machine! Team Glacier TFSI Owners Group Team V6 VCDS Map User Team Scuba Supercharged Audi S4 Audi A3 Black Edition quattro

    Seems just about right ... :D

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