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  1. #1
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    Question HELP!! can the DV cause probs? following on from my post about misfire on my s3

    well another day poking around with it and still no further forward...

    put another maf in it today incase the one fitted originally was dodgy, but still not solved

    so far we've replaced:

    sparks
    coils
    maf
    lambda
    thermostat
    fuel filter
    took out injectors and cleaned + regulator
    changed vacume pipes

    cost me around 300 quid so far and still no joy!

    it runs 99.9% fine on idle and you can drive it all day long just poodling without a problem but as soon as it comes onto bigger boost it misses and mucks about!!

    we had it running earlier and were looking about under the bonnet as my mate is sure its a boost leak although we cant seem to find one, however we noticed when you rev the car the dv (forge split-r) doesnt seem to open or close and it just closed all the time even tho the vacume to it is working fine, you can wind it out so the gap/ piston is open and it seems to drive a hell of a lot better yet still misses under heavy acceleration!! can the dv cause this sort of problem? or am i just pointing at stuff hoping?!

    i need to get this sorted as its driving me insane!!!! any help greatly appreciated

    its an APY engine
    Last edited by Rogue-24-84; 6th January 2012 at 18:03.
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  3. #2
    camscockle20vT's Avatar
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    Pcv system is your most likley culprit, check the little pipes under your inlet mani as that will be split if its never been changed, also the little braided lines around there are also worth changing. Good luck and let everyone know if you solve it.

  4. #3
    Andrew@A.L.D's Avatar
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    Swap the dump valve and i bet it will run better as the split-r is crap
    Was 531bhp 8L S3 thats going to break the 600+ bhp Club then break something else. Lets see what this OD HTAGT3582r can do
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  5. #4
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    Rather than spending loads of cash on stuff you probably didn't need you may be better off getting it diagnosed on a dyno or by road logging etc...

    Bin the Split-R as they are the spawn of the devil and put a 007/8 on it... split-r's are just no good for the 1.8t... period!!..

    Any fault codes? done any logging at all? misfires under boost can be a break down in ignition somewhere (even on new coil packs if they are not OEM ones or Hitachi assuming you have bolt downs)... seeing as you have changed all that then it seems unlikely... could also be a lean missfire too.. have seen that before where the fuel pump is on its way out... tested fuel pressure for that..

    APY being narrow band means you need a wideband AFR gauge to check under load as you won't be able to check this in VCDS..

    <tuffty/>
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  6. #5
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    Quote Originally Posted by <tuffty/> View Post
    Rather than spending loads of cash on stuff you probably didn't need you may be better off getting it diagnosed on a dyno or by road logging etc...

    Bin the Split-R as they are the spawn of the devil and put a 007/8 on it... split-r's are just no good for the 1.8t... period!!..

    Any fault codes? done any logging at all? misfires under boost can be a break down in ignition somewhere (even on new coil packs if they are not OEM ones or Hitachi assuming you have bolt downs)... seeing as you have changed all that then it seems unlikely... could also be a lean missfire too.. have seen that before where the fuel pump is on its way out... tested fuel pressure for that..

    APY being narrow band means you need a wideband AFR gauge to check under load as you won't be able to check this in VCDS..

    <tuffty/>
    yeah all genuine audi stuff, from tps..

    had it on vagcom but it showed up nothing atall.. and the managment light has never came on?!

    i have a replacement f/p so i might swap that over just to rule that out, tbh this stated after i ran it low on fuel!! but i changed the filter already, where do i take it to be dat logged or whatever? just my local garage?

    replaced the vac hoses under the inlet and yes they were all fraied etc but that still didnt solve anything
    Last edited by Rogue-24-84; 6th January 2012 at 18:42.
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  7. #6
    <tuffty/>'s Avatar
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    Quote Originally Posted by rogo-24-84 View Post
    yeah all genuine audi stuff, from tps..

    had it on vagcom but it showed up nothing atall.. and the managment light has never came on?!

    i have a replacement f/p so i might swap that over just to rule that out, tbh this stated after i ran it low on fuel!! but i changed the filter already, where do i take it to be dat logged or whatever? just my local garage?

    replaced the vac hoses under the inlet and yes they were all fraied etc but that still didnt solve anything
    Ran it low as in it ran out?... hummm... sure I have heard of this issue before... can't think off hand exactly the symptoms but I seem to recall the pump was affected...

    Would check the colour of the plugs (old skool) and see if they are black or a white colour..

    Could also see what the fuel pressure is like especially under boost... gonna be trickier without a dyno but can be done..

    <tuffty/>
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  8. #7
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    What others have said about the split-r, get rid of that crappy dv! Also, take the throttle body off and give it a clean with Wynns Carb Cleaner. Blast all the muck out of there, clean it and make sure it's dry before you put it back in.

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  9. #8
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    I would second, look at the plugs, cheap and easy and can tell alot what is going on....

  10. #9
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    Quote Originally Posted by DJ_Troopa View Post
    What others have said about the split-r, get rid of that crappy dv! Also, take the throttle body off and give it a clean with Wynns Carb Cleaner. Blast all the muck out of there, clean it and make sure it's dry before you put it back in.
    i'l get that done tomorrow, buy throttle body do you mean the bit where the butterfly is?
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    Quote Originally Posted by s3dave View Post
    I would second, look at the plugs, cheap and easy and can tell alot what is going on....
    what plugs? spark plugs? there brand new, ngk iridium ones
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  12. #11
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    Quote Originally Posted by <tuffty/> View Post
    Ran it low as in it ran out?... hummm... sure I have heard of this issue before... can't think off hand exactly the symptoms but I seem to recall the pump was affected...

    Would check the colour of the plugs (old skool) and see if they are black or a white colour..

    Could also see what the fuel pressure is like especially under boost... gonna be trickier without a dyno but can be done..

    <tuffty/>
    well not ran out as in stopped or stalled but was stuck in bad traffic on the duel carridgeway and it clicked down passed the 0mls to --- before i could get to a petrol station, do you mean plugs as in sparks? or plugs on the fuel pump? because we've had the spark plugs back out and they're still like new, wiped them over and put them back in again
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