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Limp Mode/MAF Problem????

Discussion in 'A3/S3 Forum (8L Chassis)' started by GarryX, Aug 16, 2005.

  1. GarryX

    GarryX Member

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    After reading through other posts trying to find the answer to my problem ive came to the conclusion that ive not got a clue lol.
    Anyway,i posted a while ago about a loss of power suddenly when im at a higher speed then my car has no real power or pull untill i pull over, turn off the engine and start up again.Once i do this then it seems fine again.
    I have read about limp mode and this could be reset by disconnecting the battery and ive also thought it could be a problem with the MAF.
    Have any of you guys came across this before.I have an A3 1.9 TDi.
    Id like to know if this is a problem i can fix myself before i get charged all sorts from the local dealer.
    Thanks.
     
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  3. VAGMAN1

    VAGMAN1 Member

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    Disconnect the MAF, go for a drive and see if the problem still happens - if it does then it isn't the MAF.

    I assume you know where the MAF is located and how to remove it? (if not, go to FAQ's and you'll find the info there).

    I had a very similar problem on my TDI (110bhp) and found that one of the pipes leading from the turbo to the EGR valve had disconnected - doesn't sound like you've got quite the same problem, as mine felt like it had no turbo at all. However, could be worth investigating if you have a split in a hose which is causing pressure loss at high speed/revs.

    Do you know if the turbo is cutting in at all? A way to test when the car is stationary is to have someone rev the engine, and you to hold the pipe which runs on the left-hand side (viewed front-on) of the plastic engine cover - if when you grab the pipe and the engine is revved hard, you should feel the tube pressurised/get harder if the turbo is working.

    Another thing worth mentioning is that when I had similar problems and the car went into 'limp' mode, no warning lights or anything were triggered on the dash.

    and something else - if you havn't got one already, go out and buy the new Haynes manual for the A3 - it's brilliant!
     
  4. amoani

    amoani Member

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    I had a similiar problem on my S3 (different engine i know), Was down to a small hose that had come off. Is the engine warning light coming on at all?

    Aaron
     
  5. GarryX

    GarryX Member

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    No warning lights at all guys.Seems to be roundabout 60-70 mph, i kind of feel the engine do something and the accelaration isnt that great.When i slow down or try to change gear then there is no power there.
    It definately feels like the turbo is kicking in when it drives normally,as i say,when it happens i pull over restart my engine and its fine.
    This doesnt happen everytime i hit speed though,just now and again.I noticed it always done it when the engine hadnt heated up properly yet,might just be coincidence though.
    I think i know where the MAF is.Is it the connection/plug thing at the right hand side of the main engine part (looking into the engine)(and also, im not that clued up with engines btw)??
     
  6. GarryX

    GarryX Member

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    Anyone?
     
  7. VAGMAN1

    VAGMAN1 Member

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    Yes - the MAF is located at the right hand side of the engine, on the air inlet/pipe.
     
  8. GarryX

    GarryX Member

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    Yeah,i thought that was it.Tried unplugging it and went for a short drive.Thought my A3 wasnt sounding or driving right with this disconnected so i plugged it back in.Although i was a bit paranoid in case i had unplugged something else.
    I have also tried cleaning the fuel system which has slightly improved performence but i dont feel its the way it should be.And i still have the occational problem with the loss of power at around 70mph which seems to sort its self when i turn the ignition off then on again.
    Please,if any of you guys think that you know what this is or how to sort it ,i would be extremely grateful.
     
  9. Buy a new maf , I put it off and put it off hoping it would cure itself. Eurocar parts in Possil do them a bit cheaper than Audi Lomond. It was the best £90 I spent just to have full boost again!!
     
  10. VAGMAN1

    VAGMAN1 Member

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    But if it is the MAF, surely it should feel sluggish at all speeds/revs and not just around 70-80mph.

    The MAF is the only 'plug' on the air inlet/pipe, and sounds like you've located it. Remove and take the car out and get it up to 70-80mph - see if it still does it. You can't damage the engine at all by having the MAF unplugged, so try it.

    If it stops doing it then it's the MAF, if it continues then the search continues.......
     
  11. GarryX

    GarryX Member

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    Thanks again for the replies guys.
    After reading this http://www.audi-sport.net/ubbthreads/showflat.php?Cat=0&Number=332425&an=0&page=0#332425 im beginning to think that it might be another problem altogether.This guy sounds like he kind of has the same problem although i have an A3 TDi and its not chipped.I did wonder at one point whether or not it could be the clutch.
    VAGMAN - i will try disconnecting the MAF again (glad you agree that ive located the right thing) and see what happens.If it does happen would you think that it might be the clutch??My A3 has now done around 54000 miles.
     
  12. inigoj

    inigoj Member

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    I had exactly the same problem on my A4 TDI 110, putting foot down under heavy load (going up hills) caused the turbo to cut out at 3000rpm until i reset the ignition. My MAF is the Peirburg type and was not the problem. It could be several things causing the problem. Most likely the car thinks it is over boosting. Could be leaky vacuum pipe from inlet manifold to the pressure switch on the ECU. Depending on the type of turbo could be wastegate sticking, vnt actuator sticking, vnt mechanism clogged with soot, a leak in any of the turbo side pipes, dodgy n75 valve, dodgy manifold air pressure sensor, inlet manifold filled up with crud from recirc valve, MAF. I never did find out the cause of my limp mode, but when i fitted a tuning box it masked whatever signal was causing it. doh
     
  13. GarryX

    GarryX Member

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    So would you say id be better off just biting the bullet and taking it to an Audi/VW dealership then?
    I thought that if it was the MAF then i could possibly sort it myself but by the looks of all the possible faults that could be causing it then its way over my head.Would the exact error come up if i knew someone with VAGCOM?
     
  14. GarryX

    GarryX Member

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    [ QUOTE ]
    But if it is the MAF, surely it should feel sluggish at all speeds/revs and not just around 70-80mph.

    The MAF is the only 'plug' on the air inlet/pipe, and sounds like you've located it. Remove and take the car out and get it up to 70-80mph - see if it still does it. You can't damage the engine at all by having the MAF unplugged, so try it.

    If it stops doing it then it's the MAF, if it continues then the search continues.......

    [/ QUOTE ]

    Unplugged the MAF and it drove even worse.Fearing the worst now.If its a boost leak problem,does any one know if disconnecting the MAF would make performance worse? /ubbthreads/images/graemlins/book.gif /ubbthreads/images/graemlins/cry.gif
     

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