Acceleration and stutter? help guys :)

Discussion in 'All Things Technical' started by Scutch, Feb 12, 2007.

  1. Scutch

    Scutch New Member

    Also, that knock level of 16 is fine, right? :?
  2. AndrewC

    AndrewC Active Member

    It does look like a fuel supply issue, but I'm confused, you said that you had filled it up yesterday lunchtime and it still did it?

    What happened to the 1.55bar overboost?

    Even with the wrong bag filter, it shouldn't do it with a full tank, under half is different!

    Does it only do it in second or in higher gears too?

    The bag filter supplied with some fitting kits isn't only different in size, it protrudes from the pump at a different angle and this can cause problem on hard acceleration in a straight line.

    Could also be the pump not fitted to the pickup assembly properly and moving under hard acceleration.

  3. Scutch

    Scutch New Member

    Andrew, thanks.

    I only filled up to half a tank, as I had left my wallet at work! lol. So when the test was being carried out, I only had just less than half a tank of fuel.

    The 1.55bar figure is the peak figure on my Defi's, and as such I dont know when are where that occured. However, when accelerating and hitting the problem judder, I noticed on the Apexi controller that is was actually boosting to a much lower figure, as shown above. (thankfully you're advice on checking these figures on the controller worked, as I wouldnt have known I could do that :)).

    So I too now believe its a fuelling problem. One I did not encounter before the mods and map, even running on a very low tank on occassion. Thats why I figured it must be the fuel pump and its fitment, perhaps.

    In straight line tests, there were no problems, nor did there seem to be when coming from a left turn at a junction. But I did have just a tiny smidge under half a tank, and I would have thought with this much fuel it would have eradicated the problem if it was fuelling.

    It only does it in 2nd I believe. Havent tested in 1st as I'd rather up to 2nd early on. I could test it I suppose, but as a daily drive I dont tend to drag in 1st that often.
    I came off a roundabout in 3rd to test, too. I accelerated and there was no problem. Obviously a longer time to pick up with revs and the turbo spooling, but no judder.
  4. Scutch

    Scutch New Member

    Also, this might be way off, but my last service (or service prior) suggested that I might need a new lambda sensor as the emissions were out. Could fitting the decat etc along with this 'needing replaced' lambda add to the problem mentioned?
  5. AndrewC

    AndrewC Active Member

    Unlikely with the Apexi, did Andy not comment about the health of the Lamdba sensor?

  6. Scutch

    Scutch New Member

    Nope. Not a sausage. Maybe it was ok and the dealers were trying to get some more cash ;) lol

    Only thing he mentioned was the engine tray flapping at high speeds (being removed tonight) and the Induction kit being bracketed to engine which could cause maf failure and also the 22B vents being open meshed. Now re-covered.

    Is there a problem with Scoobyteknix website, too? Cant seem to get on :?

    Cheers :)
  7. Andy.McCord

    Andy.McCord New Member

    <Hijack> Scutch, what induction kit have you got fitted? Reason I ask is I have 57i fitted and the bracket is bolted to the coolant tank, which I was led to believe avoided vibration which was known to kill maf's <hijack over>. apologies..

  8. Scutch

    Scutch New Member

    Yup. Same kit. Could you supply a picture of said bracketry? :)
  9. Andy.McCord

    Andy.McCord New Member

    So your bracket would of been bolted the same way as mine, what is Andy recommending you do to stop it vibrating scutch ?
  10. AndrewC

    AndrewC Active Member

    A nice cold air shield should be able to support the MAF and Filter and allow the convoluted section of intake pipe to absorb any vibration from the movement of the engine.

  11. Andy.McCord

    Andy.McCord New Member

    Dont suppose you got one of them in your garage Andrew? :D
  12. adz

    adz Member

    not a bad idea that :wink: ... 0_0072.jpg
  13. Scutch

    Scutch New Member

    That looks very nice. Are these available off the shelf or are they all DIY jobs? Sweet :)
  14. AndrewC

    AndrewC Active Member

  15. Scutch

    Scutch New Member

    Superb Andrew. Would that still fit with the FMIC and pipework in place? How much do you charge for making said piece? Looks great. Could probably get on with that myself to be honest, or give it to someone who could, but it would be nice to get a figure off yourself if you'd be so kind :)
  16. AndrewC

    AndrewC Active Member

    Not really got the time to make one at the moment, although I do need a new one for mine now.

    Your car will be slightly different wrt opening for intake (MAF) and FMIC pipework so needs to be done on the car for best fit.

    I've got plenty of ali sheet so I'm happy to make you a blank without the cutouts when I do mine in the next couple of weeks and you can get it customised to fit.

  17. Scutch

    Scutch New Member

    Yes please mate. That would be spot on :)

    Would this cure my hesitation problem too? ;) lol
  18. Neil

    Neil Active Member

    OOhhhhh can I have one as well mister Carr... :wink: :lol: :lol:
  19. AndrewC

    AndrewC Active Member


    I doubt my metalworking skills are up to your exacting standards :oops:

    Plus the upper profile is meant to hug the underside of a facelift ali/steel bonnet, not some overpriced plastic thing :wink:

    I'll make a few blanks when I do mine, tbh that bit is easy once my saw table and sheet bender are setup, it's the 5 hours of tidying the garage and finding the bloody things that's hard work.

  20. Neil

    Neil Active Member

    Ahhh, but you haven't seen my new bonnet have you...?? :wink: :D

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