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S3 no power and running really rich, NOT MAF!!

Discussion in 'A3/S3 Forum (8L Chassis)' started by malcolm30029085, Dec 8, 2009.

  1. malcolm30029085
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    malcolm30029085 Member

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    Can anyone help!
    i have a 1999 s3 which has been playling up for a while. iv had all the usall problems such as split hoses ect.
    i put a forge diverter valve on it, new coil packs new n75 valve new maf also had a decat fitted a while back. but
    now its running reall ritch,( i can tell from the mpg reading also stinks!)
    also the power isnt there anymore its as if its flooding itsself because if you dive it gently its ok but
    as soon as you put your toe down more than a 3rd it just seens to die!
    at first thought it was the maf so disconnected that, still no joy. also there are no falt codes present.
    then took it to jabba sport, they looked for two hours and still no joy!!
    forgot to mention that sometimes it has a spurt of power and boosts to about 1.5 bar and really goes,
    but other times it will only boost to bout 0.7 and then really struggles.
    anyone got any suggestions???
    :banghead:
    cheers

    p.s also jabbasport said that the maf was running about 11.5 % i no thats high but when they put a different one in it was the same.
    #1
  2. redrumakamurder
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    redrumakamurder Ian Da G*

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    Im not a car boffin but a few weeks ago my car was running as wat seems to be the same as wat ure is...... i took it to my good friend who's a mechanic and it turned out to be the pipe that runs from the intercooler. dont no how much else to describe it to u tbh. if u open ure bonnet its the furthers pipe forward that runs down somewhere. it has wat i call a jacket on. i no the diverter valve connects to it.

    well this had slipped half on and half off which didnt help my car at all and i had no power when i put my foot down. but then sometimes would run fine aswell. not to mention it was also making a really loud suckin noise when i put my foot down. dunno if thhis helps.
    #2
  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    What spec are you running? 1.5bar is high for a stage 1/k04 setup

    <tuffty/>
    #3
  4. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    CTS Would be my guess !
    #4
  5. s3_kev
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    s3_kev Stage2'd!!!!!!

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    :asskicking:
    #5
  6. s3_kev
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    s3_kev Stage2'd!!!!!!

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    whats that?? catalyst temp sensor???
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  7. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    Sorry coolent Temperature Sender. Can throw silly readings at the ECU making it throw random amounts of fuel at it because the ECU thinks the engine is always cold
    #7
  8. s3_kev
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    s3_kev Stage2'd!!!!!!

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    ah yeah makes sense, i have replaced mine is a very likely cause also
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  9. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    sorry i had my mind elsewhere when i typed it, but for the £20 it costs, it is a popular fail too
    #9
  10. malcolm30029085
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    malcolm30029085 Member

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    yhe tanks i will try that but wouldnt the coolent temp sensor put dodgey readings on the temp gauge in the dash?? also i am going to try a new lambda sensor and map sensor, just to rule them out.!!
    also my cars running compleatly standard thats why i was confused that the boost was all over the place!!
    can someone conferm the part no. of the n75 because i got a genuine one from tps but it was the reverse layout to the one i had on before ( the connector was the oppisite side) also the part no. was different cos they said my old one was discontinued.
    Last edited: Dec 9, 2009
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  11. malcolm30029085
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    malcolm30029085 Member

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    just standard but it will only spike upto 1.5 sometimes othertimes it ill barely reach 0.7!!:blackrs4:
    #11
  12. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Have you had the car checked for fault codes (VAGCOM or other)?

    MAP and Lambda sensors are not cheap and seems a pointless waste of cash without at least checking and logging the car first.

    <tuffty/>
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  13. malcolm30029085
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    malcolm30029085 Member

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    yhe no fault codes also jabbasport had it for two hours and used vag com so dont no!!
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  14. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    The CTS is a 2 sensor sender, one section is for the dash, and the other feed is for the ECU
    #14
  15. malcolm30029085
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    malcolm30029085 Member

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    wouldnt thhat mean that i would see the same reading the ecu is seeing?
    it runs at about 70-75c on the motorway and a roads but around town it goes up to 90c but will drop again when i get going out of traffic is that normal?
    #15
  16. ash3435
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    ash3435 flat out if in doubt

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    im sure thats normal, mine does the same.im also having the same problem.loads of fuel flooding the engine
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  17. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    The Sender has 2 sections, one drives the ECU one drives the dash, so you can have a fully working dash, but an open circuit on the ECU bit and vikie verkie
    #17
  18. ash3435
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    ash3435 flat out if in doubt

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    hi byzan, so your saying the other side of the senor could be fcuked
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  19. malcolm30029085
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    malcolm30029085 Member

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    just an update on my power and fuling problem, seems to have full boost and power when cold ( first start up). then on my drive home from work (130 mils) after bout an hour of driving it would spike on 1.5 bar if i punched the pedal but would then loose pressure to about 0.5 bar even with my foot to the floor. but then if i built up the acceleration gradualy it wouldnt get more than 0.7 bar as if there is a leak!!! but sometimes it will run with full boost and really go and there is no tell tell air noise from a split! and also the low mpg readings and smell of petrol persist through out. !!!!
    iv checked all the pipes i can cant see anything, drove with the o2 sensor unpluged..... nothing came up . tried the base map with maf unpluged nothing. thinking maybe a misfire????
    if the lambda sensor was not working wouldnt it throw up a code?? cos i aint got none.
    Last edited: Dec 13, 2009
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  20. malcolm30029085
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    malcolm30029085 Member

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    pretty sure its a split in a pipe, seeing as it dosnt hold the boost , its running ritch and alsothe spoil up sound is quite loud!!
    just need a part number for the n75 on an apy engine pls!!
    #20
  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    You might not be running rich, the smell of petrol could be from a blocked fuel filter. Stick your head under the car infront of the rear drivers side wheel and you should see a silver cylinder held by a jubilee clip. See if the smell of petrol is coming from here.

    You may well have a knackered N75 or faulty N429 valve but I would have expected an error in Vagcom.
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  22. malcolm30029085
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    malcolm30029085 Member

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    it shouldnt be cos i only changed it a few monthes back i check it still. do u know the correct part no for the n75 valve on a APY engine?
    #22
  23. Westy
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    Westy Double Dark Side! Diesel & 8P

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    In which case it probably wont be the fuel filter. I dont know the part number but you friendly dealership parts dept should be able to help.
    #23
  24. malcolm30029085
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    malcolm30029085 Member

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    ok thanks do you know the best way to check the system for a leak, could i block the pipe that goes into the inlet manifold and then put pressure down the tip just after the maf? would that be correct?
    cant think of an eaisier way to see if i have a leak somewhere.
    #24
  25. pauldazzle
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    pauldazzle Active Member

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    can someone conferm the part no. of the n75 because i got a genuine one from tps but it was the reverse layout to the one i had on before ( the connector was the oppisite side) also the part no. was different cos they said my old one was discontinued.[/QUOTE]


    You must of got the n75J valve which has the connector on the other side. It will work fine on your car, but will have a steeper boost spike than the standard n75C. Part no's for the n75 are all the same accept for the last letter. 058-906-283 (C, F, H, J)
    #25
  26. pauldazzle
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    pauldazzle Active Member

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    Knackered Diverter Valve? Standard DV is prone to failure.
    Max boost 0.5/0.7 bar sounds like it could be going to limp mode.
    #26
  27. malcolm30029085
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    malcolm30029085 Member

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    i have a forge one on there that i clean and re-grease reguarly. i checked it for suction before and it held well enough.
    #27
  28. pauldazzle
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    pauldazzle Active Member

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    When it's down on boost, have you tried turning the engine off & then on again?
    If it's in limp this normally clears it.
    Common source of boost leaks are the 2 braided pipes on the inlet manifold. i.e.Fuel pressure regulator to inlet manifold, & there's another one on the plate that the n249 & n112 valves sit. The other big weak point is the large rubber pipe from the pancake pipe to the intercooler.
    #28
  29. Welly
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    Welly VX220 SC Driver :)

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    Thats a bit of a noodle scratcher (as Flanders would say)...


    Mine doesn't do this. Says at 90 all the time, as I believe they are supposed to...

    I've also had a lambda sensor gone lately and not experienced the troubles you are having.

    Not sure if you've changed the CTS yet, but thats where I would start. Seems to be temperature related.
    #29
  30. Welly
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    Welly VX220 SC Driver :)

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    Bin the N249 valve as well whilst you're at it. Could be causing loss of boost....

    See here:

    http://www.audi-sport.net/vb/showthread.php?t=84402
    #30
  31. pauldazzle
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    pauldazzle Active Member

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    That sounds like a stuck thermostat.
    #31
  32. malcolm30029085
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    malcolm30029085 Member

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    just a quick update changed the cts and no joy still running cold and still not much power, also had a compresson test done and thats all good!! so think i will try a thermostat next
    #32
  33. noddys3
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    noddys3 Member

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    I know tHis is a different car but I had this problem on my focus rs and it turnedvoutvto be a split in a vacuum pipe mate! Sometimes it would fly then others I would have only 1bar of boost! Standard vacuum pipes on alot of cars are prone to split mate coz the material they r made from perish without much help!hope this helps you mate, bit of a long shot but it may enlighten you on the situation :)
    #33
  34. Mattfaced
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    Mattfaced Member

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    My temp gauge having trouble getting up to 90, only if car stationery. So should the gauge get to 90 and stabalise? I my car seems to run ritch while idling, if i throttle up like blip the throttle the engine hessitates then revs, are you experencing this also??
    #34
  35. h100vw
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    h100vw Member

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    It should go to 90 and sit there, rain or shine. Anything else and there's an issue.

    Gavin
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  36. malcolm30029085
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    malcolm30029085 Member

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    yhe i definatly think that as soon as i sort out the temp issue the preformance and fueling will sort it self out. gonna get a thermostat in a few days and put that on if not then gonna change all the vac pipes, then if still no joy... drive it into a wall!!!
    #36
  37. g60smit
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    g60smit New Member

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    hi malcolm, did you ever get this sorted? i have the same annoying issue! thanks
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  38. g60smit
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    g60smit New Member

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    sorry to bother you Bryan. Where is the CTS sensor located? I have the same issue with car. thanks
    #38
  39. malcolm30029085
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    malcolm30029085 Member

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    well i fitted a thermostat and that fixed the temp side of things but it is still not pulling properly, so tested the intercoolers and pipes they were fine checked all pipes they seem fine disconnected maf that didnt change anything, but have reailised that if i disconnest the batt it runs fine for a bit. dont think its going into limp mode cos if you put your foot down through the gears its ok but if your in 4 5 6 and go to boot it its dosnt go anywhere!!!!! also im spikeing at about 14psi and holding 9-10psi boost is that normal???
    #39
  40. ben_turbo1
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    ben_turbo1 Member

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    The new N75s are supposed to be opposite so I would say you have got the right one.
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