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Back in the money pit club

slowcoach3 Nov 21, 2019

  1. slowcoach3

    slowcoach3 Active Member

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    After having my last S3 for 6 odd years I had a break but recently got the itch to spend money and time fixing old cars so bought another one! Tis a lovely pre facelift example in really good condition. Overall it drives really well...
    However! I've put my bluetooth obd2 thing in with torque app and found it's only boosting to 9psi and maf reading of 130g - 160bhp - there's no codes with vcds and vac shows -22 on idle so I'm assuming no leaks, I can't find any anyway. So my question is where to start, might well be a tired maf giving low figures but would that fix the low boost or should I look at the low boost first and see if that cures the low maf figures?! Where would you start?
    It's good to be back apart from that
     
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  3. superkarl

    superkarl MAN OF STEEL

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    I’d prob start with checking the function of the actuator to see what it’s cracking open at. And log boost on Actuator only to see how that correlated with the 9psi you’re seeing. It should only be about 11-12psi I think (0.8bar)


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  4. slowcoach3

    slowcoach3 Active Member

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    I'm only using vcds lite so can only log certain channels. Might need to get a gauge and pump to see when it cracks open. The DV is the 20 year old original so might not be upto much too
     
  5. hydro s3

    hydro s3 S3 amk Team Ming Blue Audi S3

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    What about a tired fuel pump?
     
  6. slowcoach3

    slowcoach3 Active Member

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    While I've still been in the Audi family I've been out of 1.8t's, forgotten half of the nothing I ever knew 9psi on a k04 turbo should be actuator pressure! I gave it death earlier and boost would not budge beyond 9psi, maf reading 150 - 187bhp - and the car held 9 and felt decent. So I have a spare n75 which I'll fit tomorrow and see what happens.
     
  7. slowcoach3

    slowcoach3 Active Member

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    I swapped out the n75 for an old spare and it's now boosting to 14psi, result. Maf is still showing peak figures of 150g though so I'm hoping a new, genuine maf should sort that. Getting there
     
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  8. slowcoach3

    slowcoach3 Active Member

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    Only because I hate it when posts are left unfinished - I bought a new maf from Audi - fitted this afternoon and now showing 165g which equates to 206.25 bhp. Not bad for a standard 20 year old car.
    Now time to book in with Bill
     
    vanilla_ice and superkarl like this.
  9. thegoal007

    thegoal007 Another S3 owner....

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  10. slowcoach3

    slowcoach3 Active Member

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    I have no experience of that particular one, my only advice is not to buy the cheapest one. Some of them are proper *****, a tenner and reading a few reviews should get you one that does all you need
     
  11. thegoal007

    thegoal007 Another S3 owner....

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    thanks , bit of a hit and miss then.

    i bought a cabled version, probably about 8 years ago and still works with my paid version of VCD and does all needs to do.

    so for £14 maybe worth a punt. I'm sure there are a lot of cheaper ones and a lot more very expensive ones. this is still on the cheaper end of the scale.
     
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  13. Audi evu

    Audi evu New Member

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    Have you ever had trouble with erratic idling


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