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Thread: Hesitating S8

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    Hesitating S8

    Hi all,

    I'm new to both this group and the world of S8 ownership (having crossed over from the dark side of Alpina'd 540 ownership !). The reason for my post is to seek some advice, pointers or whatever - the story so far ...

    I've got a Silver Dec '99 S8 (I'll post some pics when I've got my digital camera talking to my PC again !!) which I bought from a main dealer in September. Since then I've physically had the car in my possesion for just over 3 weeks (small problem with a cracked cylinder head, but that may be another story !).

    Since getting the car back 2 weeks ago, the car has a very strange habit of misfiring when cold at around 3K rpm whilst driving (doesn't do it if you just rev the engine in neutral). When it gets to 3K, it doesn't matter what I do (foot to floor, manually try to change gear, etc) it will go no further and feels as though it would struggle to pull the skin off a rice pudding ! The only way around it is to take my foot off the accelerator and try again. This only happens the first couple of times around the rev range, after that it's fine (although still feels a little sluggish).

    It's booked back into the dealers tomorrow for them to "investigate" - their A8 specialist reckons it's the air mass sensor, but seeing as they've only just rebuilt the engine, how come they didn't notice that then - it had the problem when I pulled out of the garage after picking the car up (which I put down to it having fumes in the petrol tank).

    Have any of you ever had any similar problems or got any advice ?

    Cheers

    Richard

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    Re: Hesitating S8

    Hi Richard,

    Welcome to the forum - glad you have seen the light [img]/ubbthreads/images/graemlins/groovy.gif[/img]

    Traditionally, should an engine free rev cleanly, but then misfire under load, this would point to a problem with the ignition advance mechanism, whether mechanical or electronic. Is the engine ok once past 3000rpm when this problem is apparent?

    From the info so far, in order of likelyhood, these would be my guesses...

    1. Ignition advance - hall effect sensor for crankshaft position - this provides the motronic module with both RPM and position sensing from which, along with mass airflow info and throttle position, it derives the ignition advance. The rest is solid state so I would imagine it not firing the coil packs at all if faulty.

    2. MAF sensor - here the engine loading yields the clue - is it ok past 3000rpm?

    3. Coil packs. These have been a nightmare on S3's and TT's. You may have come across a faulty batch on your year of S8.

    4. Variable cam timing - could have been affected by the cylinder head replacement - I believe 3000 RPM is a changover point for increased valve overlap

    5. Variable inlet manifold length - the inlet manifold contains a rotating inner part which shortens the inlet tract past 3000rpm - again could have been affected during the head replacement.

    all the best

    [img]/ubbthreads/images/graemlins/beerchug.gif[/img]

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    Re: Hesitating S8

    Hi Mutley,

    Thanks for the tips - going into the problem a bit further, once the engine gets past 3K rpm it seems to be fine although it still a bit sluggish. Occasionally it'll get as far as 4K rpm before the problem kicks in, but for the most part it happens around 3K.

    The reason I say that it still feels a bit sluggish is that, whilst mine was in the shop for four and a half weeks for the cylinder head replacement (would you believe they lost the first one in transit from Germany ??!!) they gave me a one year old S8 as a replacement car (Avus silver with Blackcurrant interior on 20" rims !). This car felt very lively and handled beautifully. When I went back to my car after the new head, it didn't feel as lively. The lively factor could be down to the misfire problem, or it could be the gearbox being different (the loaner had the new gearbox - PRNDS as opposed to PRND432) - what do you think ?

    On the plus side, I'm now getting 22ish to the gallon as opposed to 18ish on the loaner ! Can't be driving it hard enough !!

    Once I've got this sorted (along with having the rear screen replaced and all four doors re-aligned !), I need to do something about the sound system - the Bose system is OK, but my BMW had the DSP upgrade in it and the sound was amazing - anybody got any ideas on what can be done to improve the sound system without ripping it all out and starting again ?

    Cheers

    Richard

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    Re: Hesitating S8

    Hi Richard,

    I had an 01 S8 with the PRND4321 gate and now have an 02 with the PRNDS gate and apart from a slightly quicker gearchange, the 02 is no quicker. I've had a few S8 loaners and again there has been minimal difference in performance (the loaners have felt slower probably because they have been filled with 95ron unleaded) The 20" wheels on my 02 do make a big difference to the handling over the Avus 18's so I wouldn't be worried about your springs or dampers just yet!
    To me it sounds an ignition related problem - very few other issues cause a 'brick wall' effect.
    Audi dealers are very variable in quality and if you go to a bad one you could end up getting fleeced for parts while they stab in the dark. Are you close to Milton Keynes and Wayside Audi? - they have been superb in my experience.
    Alternatively, and I would go this route if it were me, can you get to AMD in Bicester? They are Audi Tuner Of The Year and if they can't give you a good diagnosis after a rolling road session then no Audi dealer on the planet can... You would then be fore-armed to return to the guys who replaced your cylinder head...

    As for Bose - I can't really help here - try a post under the ICE section - there are some knowledgeable guys around. Or just drive around with the windows down, and seek out tunnels...

    [img]/ubbthreads/images/graemlins/beerchug.gif[/img]

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    Re: Hesitating S8

    Mutley,

    I'm in Slough, so MK isn't too far, but I bought the car from Martins Audi in Basingstoke, so I'm giving them a crack at rectifying the problems (and it's also free !!).

    Funnily enough, I'm going to AMD in December with a friend of mine who's having his Golf 4Motion rollerskate fettled there - maybe I'll get them to have a look at mine if it's not all sorted.

    I was tempted to go for the newer S8 like you, but couldn't find one that was quite right (colour versus spec versus money !), then I stumbled across mine whilst test driving a Merc for the wife. Mine's a bit older than I was looking for and the mileage is bit higher than I wanted, but then again it looks fantastic (Silver, Black leather, tinted windows & the 20" rims) and the money was spot on !

    As for the tunnel trick ... I can recommend the one under the runways at Heathrow to everyone - once I was lucky enough to enter the tunnel when it was empty from one end to the other ... what was I to do ? With the roof down, I dropped two cogs, floored it and enjoyed the sound of the flat six (Don't worry, it wasn't the engine being dodgy again - my other car is a 911 !). It was so good, I turned around and did it all over again !!

    Cheers

    Richard


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    Re: Hesitating S8

    Loaner would have had the later engine too.

    I am in Newbury and best local dealer is Swindon Audi. My boss uses them for his S8 (will not let Ridgway Newbury touch his car). They even have a separate A8 service adviser.

    His is a 98 car and has failed its last 2 MOTs due to CV boots and lower front suspension arms. Swindon Audi did the service and MOT and replaced everything under warranty (extended)!

    Am sure that Martins have ability to sort the problem but the trouble is that dealers are so busy that they are reluctant to dedicate a mechanics time to problem jobs when he could be working on a 'paying' job instead. Audis are too popular nowadays and most dealers do not have the infrastucture to cope!

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    Re: Hesitating S8

    Later engine ????

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    Re: Hesitating S8

    There was a model changeover in 1999 - S8's previous to this year had a 4v per cylinder 340bhp engine, the ones after have a 5v per cylinder 360bhp engine.

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    Re: Hesitating S8

    Hehe! - those flat sixes sound great - like a load of kettle drums all in sync. The S8's V8 is a bit too refined for me. I'm v jealous [img]/ubbthreads/images/graemlins/groovy.gif[/img] - I used to have a 996 but can't justify both
    [img]/ubbthreads/images/graemlins/beerchug.gif[/img]

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    Re: Hesitating S8

    Whew, just checked mine and it's a 40v jobbie - at least it said 5v on both sides of the engine cover, so I think I'm in the clear ! Whether I've got the full 360 horses or not remains to be seen - maybe I'll get AMD to put it on their rolling road when I'm there.

    My 911 is more of the "classic" variety - a 1990 C4 Cab in Baltic Blue with Linen Leather (sorry, I'll put the anorak away in a minute !). I've had it for about 3.5 years, done around 30K miles in it and loved every second ! It's just gone over the 100K mile barrier and needs a little tlc, so that'll be my next project once I've got the S8 sorted ! I used to drive the Porsche every day, but after I changed my job and started doing more miles I decided that I needed more of a motorway mile muncher than a balls out sports car - hence the 540 and now the S8 (I can't abide slow cars !!).

    Just had a call from the garage to say that they've organised an A8 replacement for me whilst they are attending to mine (I wonder which one it'll be ?). Obviously my request to borrow their RS6 whilst mine was in the shop fell on deaf ears ! [img]/ubbthreads/images/graemlins/wink.gif[/img]

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    Re: Hesitating S8

    Hi Richard! Good to see another S8 owner! [img]/ubbthreads/images/graemlins/beerchug.gif[/img]

    The other problem aside, the 'sluggish' feel may well be down to the 'reset' at the dealers. I experienced this two times now, after they've done that. The S8 adapts to your drive style, so if you're on the quick side, like me, the car will respond much better after a 100-150 miles. If you drive like a slug, your car will respond to that, and become slower, yet more economical. When you turn her in to the dealer for a diagnose (f.i.), they tend to reset everything, to standard values. Hence the 'sluggish' feel. [img]/ubbthreads/images/graemlins/wink.gif[/img]

    Nice you've got the 40V, that also means you've got the post facelift model... [img]/ubbthreads/images/graemlins/wink.gif[/img]

    BTW, what was wrong with the cylinder head? How did that happen? [img]/ubbthreads/images/graemlins/confused.gif[/img] I'm very curious about that one... Also wondering about the doors etc. Has it been in an accident?

    As to the stereo, I'm quite chuffed with the Bose, but that's personal maybe. Other than adding a sub not much can be done imho, without taking it apart. (which would be a waste IMO).

    However, if you want something really cool (and have some spare change) you might want to check out this guy's site: Steven Sailer. He has made some great installs...

    Audi A3
    Audi A4 Avant
    Audi A4 Avant
    Audi S3
    Audi TT

    That's very impressive me thinks!

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    Re: Hesitating S8

    Sven,

    Thanks for the warm welcome ! I'll bear the reset in mind when I next pick the car up from the dealers (maybe Monday next week ?). It would certainly explain the liveliness of the loaner - I think it was Audi UK's press demonstrator, so I'm sure that would have been driven slowly with care and consideration for other road users !!

    As for the cylinder head, I am told that the crack came from a manufacturing defect. From the research I did into the car, it hasn't been in any accidents, and I bought it from a main Audi dealer with full Audi warranty so have an element of peace of mind there !

    The reason I noticed the issue was that, the day after picking the car up, the low oil level warning light came on, so I topped up the oil and made a mental note to mention it to the dealer the following week. However the next day the light came back on, so I took the car to the garage, and it transpired that the engine only had half as much oil in it as it needed. They duly topped it up (with 4 litres !), and told me to keep an eye on it over the next 1000 miles. Within a week (and 250 miles) the oil light was back on so I rang the garage and their advice was to not drive the car, get it recovered back to them and they would look into it. Four and a half weeks later I get the car back with a new cylinder head and a rebuilt engine !

    As for the doors, that is much more straightforward - the car has had the windows armour tinted and to do that, they took the tops of the door frames off so they could remove the windows. When it came to putting it back together, they didn't do as good a job as they did tinting the windows, so the top of the doors don't seal quite snuggly enough for my liking (not that I'm a perfectionist or anything !).

    I'll take a look at Steven's site and keep you guys posted on what I end up doing with the hifi.

    Cheers

    Richard

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    Re: Hesitating S8

    Sorry to change the subject but what's armour tinting ?
    (I can guess but I want to know for definite?)

    Any pics of your beast ?

    Paul

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    Re: Hesitating S8

    Armour tinting is the same as normal tinting except that the tinting film they use contains something that makes the windows unbreakable (even though they would be pretty tough to break anyway, as they are double glazed !). The downside of this is that, when I turn the heated rear screen on it produces massive interference on the radio signal ! (Hence rear screen being replaced tomorrow for non-armour tinted one !).

    I'll take some pics and post them when I get it back next week - hopefully they'll valet it again so it'll be nice and clean !

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    Re: Hesitating S8

    My boss has the same on his S8. Windows are not actually double glazed as no air gap. Side windows are laminated in the same way as a front screen (ie glass / plastic /glass). The tint film is then on the inside and looks great.Has a metallic sheen in sunlight and almost black in overcast conditions.
    He does not have any interferrence problems from rear screen. Would some form of suppressor in element / airial not be better than replacing the screen?

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    Re: Hesitating S8

    Possibly, but then again I'm not paying for the new screen -it's amazing what you can get a dealer to cough up for ! If that doesn't sort the problem, then they'll have to keep looking, but it is fairly suspect as the only time I get the interference is when the heated elements are turned on.

    You're right about the looks though, it looks fantastic, particularly in contrast to the silver bodywork and chromed mirrors - that was one of the reasons behind buying this car (although I have gained a new nickname from a couple of my so-called friends since getting the car !)

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    Re: Hesitating S8

    I suppose the 'armour tints' are an additional layer, like the Pentagon, no? Otherwise there would be no need to remove the windows, as this comes standard on the S8. And it's in the Audi S8 brochure referred to as 'double glazing', although no 'gap' you clearly see two layers of glass, like two normal windows stuck together.

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    Re: Hesitating S8

    With the armour tint or privacy tint, the windows are black.

    My boss often wonders why people ignore him when he waves - what he forgets is that no one can see him waving.

    His car is Pearl white which with the black windows looks great - sounds horrid but belive me looks great and it is amazing how many people comment on it. I will try to get him to take some pics sometime.

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    Re: Hesitating S8

    I'd be very interested to see that Ju. [img]/ubbthreads/images/graemlins/beerchug.gif[/img] I was thinking on the grey tints myself (also for legal reasons), but never saw them on an S8, so please do ask him! [img]/ubbthreads/images/graemlins/wink.gif[/img]

    (We might want to take this to the other thread though) [img]/ubbthreads/images/graemlins/blush.gif[/img]

 

 

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