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problems when accelerating ???

Discussion in 'A4/S4 forum(B5 Chassis)' started by solarstu13, Jan 6, 2013.

  1. solarstu13
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    solarstu13 New Member

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    [Jan 6, 2013]
    Hi Guys,

    Im new to the forum,

    I have a problem with my 1.8t quattro sport,

    When accelerating through the gears i only get to 3000rpm then the turbo shuts off that happens in every gear its staring to annoy me , i have changed the turbo , have you guys have any ideas as im pulling my hair out with it ?? .

    Thanks

    Stuart
    #1
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  3. MaverickTDi
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    MaverickTDi Member

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    [Jan 6, 2013]
    This could be a whole host of things, literally!

    Hook your car up to VAGCOM and see what faults codes it throws out. This could save you mega bucks and time.

    Starting off with simplest and easiest, I'd check all you boost pipe plumbing making sure there's no split pipes, or loose jubilee clips etc. A technique that has proven quite effective is to use fairy liquid round all the pipe joins and whilst someone is revving the engine monitor and see whether you get any bubbles. It's common to get a pressure drop between the DV and throttle body. Which means there's a leak somewhere. AFAIK common place to leak is between the turbo outlet and intercooler elbow, there's a naff OE circlip that sometimes fails to provide a good seal.

    Coil packs? These often cause problems, most of my friends who own a VAG 20vt keep spares in their glove box. Cost around £25 new each (OEM) but assuming you have 1 potential faulty coil pack, I'd buy 1 and systematically change them one by one until you find the culprit.

    Turbo actuator? The diaphragm can often fail causing low boost pressure, you can try adjusting it but most often it will result in a replacement unit, Forge do good quality ones and reasonable prices.

    MAF sensor, that can usually throw a few curve balls but VAGCOM would pick it up.

    Does the turbo sound in good shape?
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  4. solarstu13
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    solarstu13 New Member

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    [Jan 7, 2013]
    Hi

    Thanks for the reply, i have had on the computer and there were no faults, i will check to see if there is a leak somewhere, the car boosts with no problems then just shuts off i will change the coil pack , and the flow meter see if that make any diff,

    thanks again

    stuart.
    #3
  5. MaverickTDi
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    MaverickTDi Member

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    [Jan 7, 2013]
    No probs mate. Yeah sounds like a plan checking for leaks. Does the car go into limp mode at all? That can be coil pack induced.
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  6. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    [Jan 7, 2013]
    Try unplugging the maf see what happens when my maf was causing erratic idle speeds between 500-1500 rpm it was as if some one was feeding the throttle lightly on and off, so when i disconnected it it ran/drove fine up to anything above 3k, all i will say is buy a GENUINE maf sensor if it turns out to be this !!!!!!
    #5
  7. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jan 8, 2013]
    Its unlikely to be coils.

    What does the boost pressure drop to? Does the car continue to accellerate just at a slower pace?

    try unplugging the MAF as mentioend, and also try unplugging the N75 valve.

    Check ALL pipework carefully for leaks, i chased an issue on my parents car for months and it turned out to be a split hose off the inlet manifold.
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  8. solarstu13
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    solarstu13 New Member

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    [Jan 22, 2013]
    the car doesnt go into limp mode the turbo just shuts off when going over 3000 rpm ???
    #7
  9. solarstu13
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    solarstu13 New Member

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    [Jan 22, 2013]
    hi aragorn, i havent got a boost meter it does continue to accelerate at a slower pace ??
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