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Whats causing my car to hesitate ??

Discussion in 'A4/S4 forum(B5 Chassis)' started by 951, Aug 18, 2007.

  1. 951

    951 Member

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    When you are an open road and put your foot down through the gears its fine but in traffic or putting your foot down from a low speed it seems to hesitate and jerk slightly but once the revs are up its fine. Its had new plugs and air filter recently ,ive checked the plugs and they are the right colour. Any idea's ??
     
  2. Markey

    Markey Active Member

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    Clean MAF ? is it DBW ? as somtimes the position sensor and throttle can do with some cleaning as the constent opening and closing does not register because its all gunked up.
     
  3. 951

    951 Member

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    Cleaning the maf sound like a good start ,where abouts is it as i had a quick look last night and couldnt see anything ,what dbw mean ??
     
  4. Turbo Lag FTW

    Turbo Lag FTW Hate those none insured you know who types

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    DBW = Drive By Wire throttle, I think taking the throttle intake pipe off and an inspection is what he means when its gunked up.
     
  5. truebrummie

    truebrummie Member

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    do you get any smoke
     
  6. Markey

    Markey Active Member

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    Yeah DBW Drive By Wire as said above means there is no throttle cable, its all electronicly controlled. In the case of the controller there is a little plate that the sensrors move accross if this is gunked up can somtimes do with a clean to help the contacts make better.

    The MAF is located within the airbox and looks very simolar to this.

    [​IMG]

    The intake hose that goes to the turbo is connected to one side of it.
     
  7. 951

    951 Member

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    Thanks for the info,i think mine has a cable on the throttle body though ??,i will have a go tomorrow once i get the suspension arms sorted !!
     
  8. SonicDeathmonkey

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    Mine was suffering the same. Called a green flag due out. 25 quid told me my maf was shagged. GSF sold them for 70 quid for an s4, with the old one in return.

    changed it myself piece of piss.

    sorted out the problems.
     
  9. 951

    951 Member

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    Tried cleaning mine and one of the sensor prongs snapped so now the car wont run at all,euro car parts are quoting £65 exchange for one !!
     
  10. stapo69

    stapo69 All hail the mighty quattro!

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    Just relaced MAF on mine, cost £95 exchange from Audi so prob not a bad price from eurocarparts really.
     
  11. 951

    951 Member

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    It worked out at £75 inc vat and it probably the same as the audi one anyway(had the same part numbers) .Trouble is the car is still hesitating and jumping as before . Any idea's what to look at next to sort it ??
     
  12. stapo69

    stapo69 All hail the mighty quattro!

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    I just replaced exhaust gas temperature sensors and lambda probe on my S4, made a huge difference, the car ran so much better afterwards, not sure on yours though, plugs? I dunno. Maybe worth getting it plugged into vagcom or getting diagnostics check from Audi or somewhere that can plug the car in, thats how I found my faults, might cost you a few quid but maybe save you some pennies in the long run rather than just replacing parts and hoping.
     
  13. 951

    951 Member

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    The garage down the road has the diagnostics so i think i will go and see them as like you say it will be cheaper in the long run !!
     
  14. SonicDeathmonkey

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    The green flag dude who came out to me had a van full of stuff. connected most of it to the car and found the problem asap.

    I know he was no specialist, but he did have a moustache, which goes a long way in my book.

    p.s. I am on the vino again!!!
     
  15. 951

    951 Member

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    The garage has told me the ECT needs replacing,does this sound right for the symptons and any idea's how much from the dealers ??
     
  16. Markey

    Markey Active Member

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    If by the ECT they mean the engine coolant temperature sensor then i replaced mine as it failed but all it affected was the temp gauage it was less than a score.

    http://www.audiworld.com/tech/eng47.shtml
     
  17. 951

    951 Member

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    The guy at the garage still says i need to replace the Ect but since i have replaced the maf do i need to plug it into the diagnostics to reset anything ??.
     
  18. 951

    951 Member

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    My car is still not running right,so far ive changed the plugs,ect sensor,maf and the diverter valve and its still not right but does feel slightly better. Any idea's what else it could be,as if i can't get it fixed soon the car is going the journey as im just getting sick of it now !!!
     
  19. Soupie69uk

    Soupie69uk Owner

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    Did you check all your boost hoses?

    Could be a kink in one.
     
  20. Broken Byzan

    Broken Byzan Photographic Moderator
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    Was it a genuine MAF? As i went thru 3 before i found one that worked. And that was a genuine one
     
  21. 951

    951 Member

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    The boost hoses looked ok from what i could see,the maf was from euro car parts not from an audi dealer but is a genuine bosch unit !!
     
  22. macca

    macca Member

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    is everything standard? have you replaced dump valve or air filter with something else?
     
  23. 951

    951 Member

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    The car had a superchip fitted years ago before i bought it and was running fine for about the first 6 months of my ownership. The only things i have changed are just the standard parts to try to fix it !!.
     
  24. 951

    951 Member

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    I was driving the car yesterday without the radio on and the window down and i noticed when changing gear im getting a ppsstt noise which sounds like an atmospheric dump valve (but quieter) is this normall or a boost leak ??
     
  25. Markey

    Markey Active Member

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    depending on boost you can hear the normal recirc valve which makes the exact same noise. I would expect you to hear a normal atmos dump valve if the windows were up or down. A boost leak would be more notiable when you put your foot down and you notice a lot less power than normal.
    Have a loook at the dump valve it might be a half and half one with the setting turned down to only dump a little to the atmos.
     
  26. 951

    951 Member

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    The dump valve is jsut a standard plastic recirc type with no adjustment,the car sometimes lacks a bit of power but most of the time is fine,its just when you put your foot down usually in 2/3rd gear but sometimes on all it hesitates.
     
  27. Markey

    Markey Active Member

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    Mine does that for a split second then carries on going i put mine down to the MAF
     
  28. 951

    951 Member

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    To be honest i expected it to be the maf but i have replaced it with a brand new genuine bosch unit ,but i suppose it could be faulty. Also there is no fault codes showing up either.What about the coil packs or injectors ??
     
  29. 951

    951 Member

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    I spoke to a mechanic today and he suggested the wastegate could be at fault ,does this sound like it could cause the problems ??
     
  30. g60leigh

    g60leigh Well-Known Member

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    i had similar problem that was cured when i had the actuator on the turbo replaced.
     
  31. Broken Byzan

    Broken Byzan Photographic Moderator
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    is the waste gate rattling?? thats what they usually do when they fail
     
  32. 951

    951 Member

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    No, not that i can hear !!
     
  33. 951

    951 Member

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    If you for example put you foot down at 60 in fifth gear the car picks up no problem but if you let you foot back off the gas then it jerks and judders,i think is looking like something turbo related ??
     
  34. g60leigh

    g60leigh Well-Known Member

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    I had the same thing before replacing the actuator. the one on mine was coroded up.
     
  35. 951

    951 Member

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    How much is a new one going to cost ??
     
  36. g60leigh

    g60leigh Well-Known Member

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    forge do an uprated one, but I believe they are a real pig to set up
     
  37. Passatman

    Passatman New Member

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    I had the same problem, hesitation on part throttle acceleration...changed (supposedly long life) fuel filter, presto! Problem solved!
     
  38. Bushen

    Bushen Driving with style

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    I had a similar problem where my car was hesitating aswell and i changed the Maf, the spark plugs, the h.t leads and that helped a little bit, but the problem was resolved when i changed the coil pack, dont know if its the same for your case but maybe its worth a go.
     
  39. 951

    951 Member

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    I ve changed the fuel filter which made no difference,i think its either down to the actuator or the coil packs like you say. Anyone know if the 1.8 n/a uses the same coil packs as i knoiw where there is some that i can borrow !!
     
  40. Broken Byzan

    Broken Byzan Photographic Moderator
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    Sadly The NA one s are different
     

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