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2.5Tdi EGR Problem?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by herisites, Jul 10, 2011.

  1. herisites
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    herisites New Member

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    Hi guys,

    I've got an '01 A4 2.5Tdi which has been off the road for a while so am currently getting it sorted out to put back on the road.

    Before it came off it was having issues with irratic boost and going in to limp mode. So I've used the Innotec Turno Cleaner on the turbo assuming it was coked up, it feels better but it still goes in to limp mode.

    So I suspected EGR. Now I've done some searching and it seems like my issues slightly different to others who disconnect and plug the EGR vacuum pipe to make it better, however when I disconnect the vacuum pipe from mine and plug it, it feels the same but if I leave the pipe unplugged and breathing then the car feels much happier and doesn't go in to limp mode.

    I blanked the EGR off yesterday and left the pipe connected and it was flat and went limp.

    So not sure what the issue could be? Which is the N75 valve? Could it be that maybe? I'd just leave the pipe disconnected for now but that means it'll be sucking in un-registered air won't it?

    I appreciate any help!
    Last edited: Jul 10, 2011
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  2. BlackQuat
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    BlackQuat Well-Known Member

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    HAve you had it on vcds?
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  3. Turkster
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    Turkster Bro.Paul 2.5TDI Quattro Sport

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    ah iv had this one mate,

    down the front of the engine bay are 2 valve controllers, with air pipes that come off them, suckers, the big one on the right was the main problem for my car as it was faulty and was stuffed and caused me loads of head aches, this faulty unit also made my EGR get dirty and worn badly due to the ill messages from the valve at the front, you will find the said valve infront of the ABS pump, infront of the block plugs for the electrics if you get my drift?

    im in Northampton if you want to pop over at some point?

    Paul
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  4. herisites
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    herisites New Member

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    Cheers for your help Turkster, I know the parts you mean, I followed the vacuum pipe from the EGR to them and wondered if one/both of them could be on the blink! Was it expensive to replace?

    I've had it on VAG-COM before when it was having other electric issues (thought to be convenience ECU but turned out to be broken wires in the drivers door!), not scanned it since I fixed those issues though as I used a mates before and don't have it myself.
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  5. Turkster
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    Turkster Bro.Paul 2.5TDI Quattro Sport

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    part was about £50 from Audi mate, the other is less, Ebay can be us-full, like i said, im in Northampton so pass by if you close to hand,
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  6. herisites
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    herisites New Member

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    Cool, not too horrendous then!

    I've had a look on vagcat and I believe the 2 valves you mean are 29 and 31 in the diagram here:

    Audi A4/S4/Avant quattro 1998

    I think 29 is the N75 valve isn't it? The part number matches an N75 valve being sold on ebay anyway. I need to check the part numbers on mine in case they changed on the B5>B6 switch over.

    Do you have VAG-COM mate? The Audi's not on the road at the minute but getting it MOT'd friday so should be by next week.
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  7. Turkster
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    Turkster Bro.Paul 2.5TDI Quattro Sport

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    Iv not got VAG-COM yet mate,
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