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Help! - Issue with the red devil...

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by BLP, Mar 1, 2009.

  1. BLP
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    BLP Member

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    Have an issue with the red devil (J7uss's old motor):

    Right so car was running great last night, jumped in this morning, no issues, fuel was very low so went to fill up, car runs fine when running low rpm but the moment the turbo gauge hits about 15Psi (When I put my foot down) the car judders - The gauge never shows anything above 15Psi now, it usually hits 25 no probs,

    When it did it on the way to the pumps I guessed it may have been some sh1t in the fuel lines from being near empty but filled up and its still doing it.

    I love sorting issues out - otherwise I would have bought a lower mileage car - BUT - I am no mechanic! - Can anyone help ?

    :redrs4: Ben.
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  2. J7USS
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    J7USS Shuddup Foooool!!

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    :faint:, Oh my god, what you done it it.;)

    Have you checked coil packs mate??? I put 4 new ones in about 6months ago...
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  3. BLP
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    J7USS:faint:, Oh my god, what you done it it.;)

    Have you checked coil packs mate??? I put 4 new ones in about 6months ago...



    Buggered it mate - complete write off - all your hard work down the spout ! :laugh: joke.


    Will check em, just bought me haines manual form Halfords lol - save me texting you all the time !

    :redrs4: Ben.
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  4. J7USS
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    J7USS Shuddup Foooool!!

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    Hey mate, I dont mind at all text/phone/email whatever, Im happy to assist!!

    Did you say it was hitting 25 psi all the time, Im sure it only hit 15-16 with me...

    Haynes manuals are a good thing but Id make sure you havnt put diesel in it..;)!!

    Check coil Packs then check for any pipes down near the Diverter valve/Turbo to see if any pipe has blew off, I had issues with it just after my remap but changed all the clips and it was back to life again...

    Dont think it would be the hyperboost as thats pretty new aswell. Id say there is a Pipe that has came off. Check the Big thick pipe on the right front side of the Engine that goes into the....erm, dunno what its called...You cant miss it.
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  5. BLP
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    Ok cool cheers mate, another possibility is I was farting around the headlight area before I started driving it, anything I could of knocked around there u reacon? - Clumsy fool that I am - or might have been... :banghead:

    :redrs4: Ben.
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  6. evilscotsman
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    evilscotsman Space Cowboy

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    the N75 valve plug on ok? Its behind the drivers headlight mate. Its a wee black cylinder with 3 vac pipes and a plug connector, thats the boost control valve.

    Is there no DTC lights on the dash when it judders? I would think there would be, even with dirty fuel the ecu should flag misfires, fuel pressure or boost issues on the dashboard.
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  7. BLP
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    Sounds a good possibility, have had a good look round, and everything appears to be connected fine, nothing comes up on the dash, someone mentioned it might be running in limp mode, is this a possibility?


    :redrs4: Ben.
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  8. 1wheelonly
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    1wheelonly cabriolet

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    if it was in limp mode then as far as i know youd have the engine management light on mate.
    sounds like coil pack
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  9. BLP
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    ok - cheers - how do I know if a coil packs shot or not? or is it a case of replacing all of them, to rule it out, I cant hookup to vagcom until tomoz when my mates back :mad:

    :redrs4: Ben.
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  10. evilscotsman
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    evilscotsman Space Cowboy

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    unplug them one at a time, starting the engine after each one is off, disconnecting a good one will make it much worse and when you remove the bad one it will run just like it is now, no change, and youve found the culprit.
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  11. J7USS
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    J7USS Shuddup Foooool!!

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    If it is coil pack then Ill ring audi up where I got them from because I'll tell them I aint happy that they have gone again and aint even 8months old.
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  12. BLP
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    Have now checked the coil packs in turn - no problems with them at all and N75 valve seems untouched - the car is running very smoothly as it should, its not until I put my foot down it has a fit and its at the same point religiously, even goes as it should with the turbo spinning at like 10psi,

    Also - Nothing came up on the dash when I disconnected the coils in turn, is this normal? I was definatly doing it right as there was an obvious difference when each was disconnected.

    Ummphhh........


    :redrs4: Ben.
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  13. 1wheelonly
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    1wheelonly cabriolet

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    is it like an instant misfire or is it slugish like fuel starvation?
    is it doing it whilst reving stationary or just under load,in gear driving?
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  14. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    spark plugs and/or plug gaps?

    I dont know whats in there, but some BKR6E's or perhaps BKR7E's if its making big power, gapped to 0.028" should do the trick.
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  15. BLP
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    Its like an instant miss-fire with a short-term loss of power, if you keep your foot down it just keeps juddering until you let off back to where its happy?

    There is absolutly no differentiation / problem at all until its up to that point i.e. it idles very happily and runs great until then.


    :redrs4: Ben.
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  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    If its ONLY under load, then the spark plugs would be my first point of inspection.

    Its not the coils if it idles and drives fine off boost/low boost.
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  17. BLP
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    Cheers, I shall check those too, please excuse my complete ignorance but I am not as familiar with this engine not ever having one before but I want to check any piping around the turbo area like Juss suggested - save me a bit of time - Where abouts is it actually located? :laugh:

    Also - what should I be looking for as regards to the spark plugs?

    :redrs4: Ben.
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  18. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    just general condition of the plug and most importantly the gap.

    Plugs wear and the gap increases, it eventually gets to the point where the gap is too big and the spark isnt strong enough to ignite the fuel in the cylinder. This becomes most prevalent under boost as its generally harder to ignite a cylinder at 200% VE than one at 100% VE
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  19. J7USS
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    J7USS Shuddup Foooool!!

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    You want to be checking all the pipes from the Left hand side of the engine where you'll see the biggest one going into the Turbo unit. Its tight down there so watch your hands, mine got shredded up, mind you I was just impatient AGAIN! If you have access to a 4 poster then that would be the easiest and quickest way - you seen my drive mate, Once i jacked it up, I could hear it sinking so i went through the top.

    Take of the Air intakes, remove the headlamp and you'll have a clearer shot at it. Im guessing that where your problem is as it happened to me just after the remap but I always did a check every now and again as I didnt want it happening again...

    Start with the biggest pipe going into the turbo then all the surroundin pipes including the pipes that are going into the Diverter valve. The por thing is just missing the J7uss 'Gentle' touch ha!!
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  20. BLP
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    Cheers Juss, will check that now, spark plugs just been out and checked - no problems there,

    :redrs4: Ben.
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    BLP: did you check the gaps?
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  22. BLP
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    Yep they were all gapped the same pretty much as per your suggestion.

    :redrs4: Ben.
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  23. pjmspeedy
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    pjmspeedy Dude, what's mine say ?

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    Sounds like it's over boosting to me! hence why it judders and holds it back. You need to check for any splits in the pipes.
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  24. BLP
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    Yep thats what I reacon mate, getting underneath her tommorow, cheers


    :redrs4: Ben.
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  25. BLP
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    Have gone in from above, removing the air intake, headlight etc and done (to the best of my ability) an evaluation of the hoses, I cant seem to find any split or removed but I dont know how much better access I would get from going underneath?
    I am not ruling it out now as I really dont know what im looking for anyway but need the car for tonight and slowly giving up (with my own ability more than anything!), thinking maybe a mechanic can diagnose it alot faster than I can on my first attempt.

    Anyone know anything about Audi's in Newbury / Thatcham, Berkshire area? :p


    :redrs4: Ben.
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  26. J7USS
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    J7USS Shuddup Foooool!!

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    Ill get to the bottom of it tomorrow Ben, Ill give you a bell mate!
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