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Not holding boost.....any suggestions

Discussion in 'A3/S3 Forum (8L Chassis)' started by hooley, May 27, 2007.

  1. hooley
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    hooley Member

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    [May 27, 2007]
    Hi,

    Took the 1.8TQS to Chipped UK for a re-map

    Dyno before: 156bhp - :scared2: well pee'd off - it's supposed to be 180

    After :189bhp with the acknowledgement that we would be over 210 if the turbo would maintain boost. There was a leak/early DV operation- unknown problem. They also thought there may be a problem showing on the dyno, but might not see it on the road.

    I do notice what seems like the turbo slowing, acceleration not quite as it is at 2,500rpm to 4,000 rpm.

    I pointed out that the pipe from the intercooler to the throtle valve had been hacked in to to add a dump-valve, and whilst I had removed the DV I left the branch pipe in.

    They said it would have an effect - so I replaced it on Friday with a shiny new Audi OE part, a little difference.

    Could it be the turbulence that this caused, or could the Diverter Valve that I replaced into the system, (when I got rid of the dump valve) be the problem. I got an OE Audi part. All pipes seem good with no splits or aparent problems with junctions...

    Any suggestions???

    Must say the turbo now kicks in hard

    Cheers
    Jas
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  3. rodenal
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    rodenal Active Member

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    [May 27, 2007]
    Im surprised they mapped it knowing there was a problem with the car - have u had the turbo itself checked
    #2
  4. shineydave
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    shineydave Member

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    [May 27, 2007]
    playing devils advocate i'd agree with rodenal. you can't map a car with a fault so it looks like whatever they've done has been a waste of money.

    chipped UK ain't specialists and so won't have a clue about some of the more "unique" issues we experience. at the risk of being accused of being Dougs love toy i'd advise you to get it down to MRC and let them have a look at it.
    #3
  5. hooley
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    hooley Member

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    [May 28, 2007]
    wasn't a problem at 156 bhp. only the low figure.
    After the map, much better, but a sense that the turbo works for the first few seconds after 2,500rpm, then tails off if you keep accelerating.

    or is it the wave of torque gives way to the power curve? so it is a sensation rather than actually happening?

    jas
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  6. rodenal
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    rodenal Active Member

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    [May 28, 2007]
    a 1.8TQ at 156bhp has a problem, no doubt about it - they will have a tollerance out of the factory but we're talkin 5bhp or so, the map sounds like its just amplified the problem ,id be asking for a refund if i were you.

    Unless of course their rollers are just way pessimistic - turbo shouldnt tail off until 5kish
    #5
  7. shineydave
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    shineydave Member

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    [May 28, 2007]
    did they do any fault logging or perform a pressure test on the inlet?
    #6
  8. fazzybear
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    fazzybear Member

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    [May 28, 2007]
    Actuator?
    #7
  9. hooley
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    hooley Member

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    [May 28, 2007]
    The fault was assumed to be the Intercooler to throttle pipe wich had a t-piece in it where the removed dump valve came out. Thought to be causing the pipe to swell....not sure as it was a bailey valve with silicon hoses.

    This has now been replaced with a new hose from Audi...

    Will look at the rest of the pipes to see if we have any splits or loose connections

    Jas
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  10. hooley
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    hooley Member

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    [May 28, 2007]
    Give me a clue where it is and i'll look

    jas
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  11. shineydave
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    shineydave Member

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    [May 28, 2007]
    actuator is clagged on the side of the turbo.

    i think i'd be disapointed in that they thought there was a problem but have done little to get to the bottom of it. my intercooler pipes swell all the time but that's down to the 15psi of pressure going through them. even if they swell you'd still have the same amount of pressure in there so it seems like ****** to me.

    was it a custom map or a generic one?
    if it was custom you need to go back once you get to the bottom of the problem as they'll have customised the map to the fault. that's why i asked if it got pressure tested and the fault codes checked before mapping.
    #10
  12. Ballcrusher
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    Ballcrusher NO CAT JUST 3" STRAIT THREW

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    [May 28, 2007]
    check all the vacum piipes under the engine cover as i had a problem with loss of boost pressure and turned out to be split pipe sorted cost £2...lol
    #11
  13. nershen
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    nershen New Member

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    [May 29, 2007]
    You need to find someone with the VAG COM software and log blocks 114 (n75 duty cycle),115 (requested+actual boost)and 003 (maf readings).

    There's a whole lot of reasons why your car could be losing boost. I think 114 will tell you if the N75 is working too hard, if so, it's probably a boost leak. 115 will tell you actual vs requested boost. If they are similar, then it could be something else wrong, and not necessarily a boost leak. 003 will tell you if your maf is stuffed.
    #12
  14. madvw
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    madvw Active Member

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    [May 29, 2007]
    Blimey, isnt that rule number 1 of tuning?

    "Make sure car is 100% before tuning"
    #13
  15. hooley
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    hooley Member

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  16. hooley
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    hooley Member

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    [May 29, 2007]
    Offending pipework removed and replaced with stock.

    Not sure if it was the problem though, as the end was capped.
    The tuner at Chipped UK was Jason (the Owner) and he said it was probably due to a turbulence effect in the pipe, reducing boost.

    Jas
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  17. hooley
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    hooley Member

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    [May 29, 2007]
    The car had just had a major service, with new sparks, air filter, fully synthetic oil (mobil 1) and has had new cambelt/waterpump/coolant and a haldex service in the last year. All should be A1 condition......

    It was only on the dyno that the problems arose.

    Jason
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  18. hooley
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    hooley Member

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    [May 29, 2007]
    Cheers,

    Anyone near Chesham / Hemel area with a VAG-Com?
    #17
  19. rodenal
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    rodenal Active Member

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    [May 29, 2007]
    I think the point people are trying to make tho is that the dyno showed there was a problem with the car - even if its running perfectly at 150 odd bhp its not right, something is the matter with the car.

    Most responsible tuners wouldnt do anything to the car until it was packing roughly what it should from the factory

    It also means u have no idea what the car is now running at now
    #18
  20. fazzybear
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    fazzybear Member

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    [May 29, 2007]
    Actuator is a little silver cylinder shape which holds the boost while the turbo spools, replaced one on my old R5 and it sorted the boost problem
    Has a metal rod coming from it too

    please correct me if im talking b o l l o x
    #19
  21. shineydave
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    shineydave Member

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    [May 29, 2007]
    nope, that's about right for the actuator.

    as rodenal states, a responsible tuner would never have touched it. sounds to me like all they were interested in was getting your cash in their pockets with no thought for the consequences.

    if the engine goes pop now what recourse do you have with them since they've clearly laid a remap on a sick engine. if it has a boost leak mapping it will only make it more pronounced with the result, in the worst case, of the turbo letting go and extensive upper cylinder damage.

    i think it's clear from your experience that these bargain tuning shops are anything but cheap. you need to go back, get the map removed, your hard earned back in your pocket and take a trip to a reputable specialist like MRC who'll sort it properly.
    #20

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