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Lumpy idle

razza1 Nov 14, 2015

  1. razza1

    razza1 Registered User

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    I had a slight misfire a while back, changed plugs and seemed OK, however noticed some oil on one of the coil packs.

    Since getting the car back from having the clutches done its feeling lumpy again on idle. Getting vibrations through the car and the revs ever so slightly jump around (barely noticeable unless you knew it was there and staring at the needle). It's worse than before.
    Done full derailed scan on carista and no errors, with no dash errors either.

    After all my gearbox issues I can't afford big bills again, any ideas of what it could be?
    Should I try injector cleaner? Any recommendations?

    Would coil packs be the best route and can you buy individual or is it best to replace all at same time? Given I'm stage 2 would OEM cool packs be best or any upgrades whilst I'm doing it (conscious of price...)?

    Feeling hacked off :(
     
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  3. Sluggy007

    Sluggy007 RS3 FL Saloon

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    I have a s4 on a 15 plate. It's done 10k now and I'm also getting a slight judder at idle. Again no errors but can feel it through my seat while in traffic so to say. It don't happen all the time though. Audi Southend took a look and can't find anything.......... anyone else got this? Maybe a chacteristic of this engine?
     
  4. scotty76

    scotty76 Registered User

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    My 14 plate has done this from new. I think it's a characteristic.
     
  5. razza1

    razza1 Registered User

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    Really? That's a **** characteristic." For something that should be a premium car...
     
  6. scotty76

    scotty76 Registered User

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    If you Google you'll see plenty of posts about this. I agree it's not great but it does appear to be normal.
     
  7. Scott.T

    Scott.T Registered User

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    My S4 didn't do it but my 1.8TFSi did, which I thought was strange. I did read that the TFSi does something clever and changes the mixture around at idle, so I put it down to a mode change.
    The TDi doesn't but just sounds like a tractor ;)
     
  8. benjie

    benjie Registered User

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    Carbon build-up?
     
  9. xpoweruk

    xpoweruk TTTS 8J Smile Machine

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    If it didn't do it before then I would say it isn't normal.

    how did oil get on the coil packs?? Is it on the oil filler side?

    Have you tried taking the plugs out to if any signs of an issue ?
     
  10. razza1

    razza1 Registered User

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    Only replaced them recently, as did have a very slight misfire before.
    It had oil inside the tube going up from spark plug to cool pack. Only on one, others were fine
     
  11. razza1

    razza1 Registered User

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    Stuck injector cleaner in it and a full tank of shell, been using tesco 99 previously so will see if it's a fuel issue or not
     
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  13. jaygemson

    jaygemson Registered User

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    First thing I was going to ask was are you using Tesco fuel.

    My car ran brilliantly on Momentum 99 but it idled terribly. I know of another MRC tuned S4 who had exactly the same thing. I reckon with a couple of tanks of Shell V-Power the lumpiness will disappear, but as others have said and you may have noticed before, you can definitely feel the engine rocking on idle through the seat. That's sadly an S4 'thing', but I quite like it frankly - maybe I'm weird!
     
  14. razza1

    razza1 Registered User

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    I'm ok if it's a normal trait, just with my prior luck am just nervous now, and seems a bit odd..
    I'll stick to the vpower for a bit and see how that changes things
     
  15. ub7rm

    ub7rm Registered User

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    Mines the same. Wouldn't go as far as saying it's a misfire or anything like it but you can feel a little unevenness in idle when it's hot.

    My mk5 GTI did the same, S3 didn't strangely as it was almost the same engine.
     
  16. razza1

    razza1 Registered User

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    Yeah guess I wasn't sure what to call it, no misfires when scanned, just vibrates around a fair bit
     
  17. Dippy

    Dippy Registered User

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    Interesting. I shall keep track of this thread. Mine seems OK.
     
  18. razza1

    razza1 Registered User

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    Been giving it a bit of a boot and a couple of days in, can't say for sure but think it's slightly easing...maybe it was the tesco 99 fuel...
     
    jdp1962, xpoweruk and V6 Quatt like this.
  19. V6 Quatt

    V6 Quatt Registered User

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    Stick to premium brands if you can!!

    Hope you sort it Razza
     
  20. xpoweruk

    xpoweruk TTTS 8J Smile Machine

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    Was it mapped on Vpower ?(curious)
     
  21. razza1

    razza1 Registered User

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    No idea, but used 99 on previously remapped cars and was fine
     
  22. razza1

    razza1 Registered User

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    Seems to have pretty much disappeared. Only gone through half a tank and that was a 50/50 mix of momentum and vnitro+, so when run down I'll do a full tank of the nitro one.
    I think it must've been the fuel, and now wonder if I changed my plugs for no reason a few months back...
     
  23. xpoweruk

    xpoweruk TTTS 8J Smile Machine

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    Hopefully this is the end of ya S4 woes mate.

    Then ya can get on with enjoying her again :)
     
  24. razza1

    razza1 Registered User

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    I really hope so buddy
     
  25. jaygemson

    jaygemson Registered User

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    Sounds promising.

    MRC swear by Momentum fuel and get their best figures on it, although this may be that Tesco is their closest filling station so when cars are filled there the octane rating is as high as it can be (rather than a tank of V-power a customer drove there on that was added to the tank a week ago, for instance). No coincidence that me, PMJ and now yourself have all suffered the same problem on Momentum fuel though if you ask me.
     
    razza1 likes this.
  26. razza1

    razza1 Registered User

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    Interesting, so not just me then. To be honest I'd rather lose a few bhp and not have a vibrating idle..
     
  27. razza1

    razza1 Registered User

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    Guess with tesco you get a 99 fuel whereby the shell version isn't guaranteed I believe as it doesn't mention the rating on the pump.
    Plus you get tesco points as well on it which always helps when filling up a lot :)
     
  28. Dippy

    Dippy Registered User

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    Try to find proof that either Tesco Momentum or Shell V-power are 99 RON and you'll struggle. It is possible to find a product information sheet for the latter which has the words "Shell Guarantee 99 RON" on it, but it still just shows compliance to BS7800 for 97 RON. I really don't know about the subject but my guess is that the only guarantee we can even get is 97 RON and can only hope that the suppliers are giving us better.

    The thing is now that there have been too many complaints about a 'bad batch' of Momentum, including at MRC. Remember that Tesco is still in financial difficulty and its core business is competing with Aldi and Lidl for cheap groceries. Their petrol stations are there just to lure customers. Whilst I do think that they genuinely made a good move supplying Momentum as a 99 RON fuel to attract a niche but probably lucrative market, I'm not sure that I would trust them any more over it. Lets face it they got into trouble with their profit statements. If they were publicly willing to risk their brand with false accounting then I'm sure they are prepared to loosen their requirements over exactly what fuel they sell as Momentum.

    On the other hand oil and petrol is Shell's core business and they have a valuable brand. I don't think they will risk it.
     
  29. razza1

    razza1 Registered User

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    I know there's been bad batches of other fuel at tesco, so maybe I'll need to stick with shell.
    Momentum has 99 on the pump though, so would assume they need to supply it as such, but get your points about motives...
     
  30. xpoweruk

    xpoweruk TTTS 8J Smile Machine

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    I could only find a batch test for momentum 99 from 2012,it came back at 99.5
     
  31. Scott.T

    Scott.T Registered User

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    I run a KS3 knock detector and a PFC ECU with knock monitoring on my other car and I have never had a 'sparkle' with Tesco momentum.
    I have mapped the car to the optimum ignition advance and as the ECU has no closed loop knock control it just runs what I tell it.
    I used to run the occasional tank of V-Power (until my local shell changed to BP) and saw no difference in knock output or performance. However it's predecessor Shell Optimax did cause cold running misfires and it would loose octane over time (the car doesn't do many miles so a tank full could last weeks/months)

    If I swap to Esso or BP Super I do get an occasional light sparkle on both Knock detectors.
     
    xpoweruk likes this.
  32. Dippy

    Dippy Registered User

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    As you might have noticed I am a bit cynical :) Unless I mis-remember there is a type of ice-cream that you can get called a '99'? Should we assume that it has 99 somethings in it? Or maybe its just a number. I have no doubt that Tesco have every intention that Momentum 99 is at least 99 RON, however without clearly stating that it is 99 RON and the assumption that it only has to be legally 97 RON to meet BS7800, I am ready to believe that a batch could be supplied which is less than 99 RON. I'm not sure how the refineries produce the stuff but surely it is batch related and I guess they do still test it on a 'research' test engine? If they have a batch of fuel which is less than 99 RON but more than 97 RON what's to stop it being sold as Momentum 99?

    For me its academic since there are plenty of Shell stations for me to go to but getting to a Tescos is a major diversion. Plus my S5 is stock so I could get away with 95 RON anyway.

    Scott's post is interesting.
     
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  34. rum4mo

    rum4mo Registered User

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    My local Esso station gives Tesco points, but like Dippy, I run 95 RON !

    I thought that the final "adjustment" in octane levels in petroleum spirit, at least from mainland Europe refineries, which is where Tesco source its fuels, was down to loading in more Benzene or some other seriously cancerous cocktail.
     
  35. xpoweruk

    xpoweruk TTTS 8J Smile Machine

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    isn't it 5% bio-ethanol ?
     
  36. rum4mo

    rum4mo Registered User

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    "bio-ethanol" - is that not a rude word? a friend at work was taking his Mondy to France a couple of years ago and Ford UK dealers could not tell him if or what level of "bio" petrol was okay to dump in the tank, which initially concerned him! Closest I've knowingly come to bio stuff was when I discovered that a nasty little furry thing had targeted the light weight foam stuff under the bonnet of my S4, caught him and his mate!

    Back to "octane boosters" - it is Benzene that gives all the higher octane rated petrols their "fantastic" smell, it might hurt you, but it does smell good!
     

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