’Jerkiness’

Discussion in 'Engines' started by redbaron, May 17, 2004.

  1. redbaron Forum Member

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    My 92 8v mk2 has an annoying fault when accelerating and decelerating. As you just put your foot on the throttle or take it off it 'jerks'. This is fine when caning it but when trying to be gentle with the throttle round town and stuff its just annoying as it looks as if im a sh1te driver.

    Any suggestions? Have checked throttle body and it seems to be operating smooth, seems to run on by itself for a bit once the throttle is closed?

    Idles at 1500 rpm sometimes untill you blip the throttle then it settles back to 950.
    [:s]
     
  2. buzzby Forum Member

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    Sticking throttle cable?

    is there resistance in the throttle when you push it down and does it come back up smothly.

    Maybe spray some wd40 where the throttle cable connects to engine as this may also be sticking. Sorry don't know what the thing is actually called

    Buzz
     
  3. PaulM Forum Member

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    could be knackered engine mounts
     
  4. Lloydieboy79 New Member

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    same happens to mine. got so fed up, i pulled the head off it at the weekend. once ive rebuilt it, i'll post again and let you know what the problem was
     
  5. H8SV8S Forum Member

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    Engine mounts
     
  6. setgti Forum Member

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    Reset the throttle switch settings and idle speed. If you can't stand it (like I couldn't) unplug the switches by pulling the connector off. The connector is just behind and above the intake manifold.
     
  7. redbaron Forum Member

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    How do i do that then? Reset the settings.
     
  8. redbaron Forum Member

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    Car has only done 83k and was owned by a lady (assume it wasnt driven hard) is it likely to be engine mounts?
     
  9. buzzby Forum Member

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    Can you move the engine if you hold the top and try to push it forward and back. If there is a lot of movement then it prob is engine mounts
     
  10. ywouldi New Member

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    I had this problem on my Mk2 the other day, was really jerky, and like you say, quite embarrasing! Turned out to be the engine mounts which were replaced with no labour charges by the garage that I bought the car off.

    Its a lot lot better now, if they are rubber mounts, maybe yours have just perished over time.

    Ben
     
  11. chrismc Forum Junkie

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    I reckon your all wrong..... ;)

    It sounds like jerkiness from the overrun fuel cut-off..

    All digifant cars suffer(ed) with this to a certain extent & it manifests itself as a slight jerk/hesitation when going on/off the throttle as the overrun fuel cut off is actuated by the throttle closed microswitch. You also get hesitation when trying to do a fast gear change when driving hard....

    Depending on each specific car it can be relatively mild or particularly noticeable.

    The cure is to have the car ECU remapped (as mine was by AmD) Part of this service includes re-scheduling the amount of fuel allowed into the bores during an over-run condition & thus smooths out the throttle & generally improves driveability & response..

    I believe AmD no longer re map mk2 digi 8 valves so your best bet is to contact Stealth Racing...

    A new set of engine mounts with a mapped ECU will transform the car & totally remove any hesitation/baulking!
     
  12. setgti Forum Member

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    Except for me, when I said disconnect the switches. I HATE overrun cut off and I have left my car without the switches connected.
     
  13. baxter basics Forum Member

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    Mine does it.

    I have replaced all the engine mounts, thoroughly checked the digifant fual/air/ign setup, replaced the wishbones, checked the wishbone mounting points

    still does it.

    I think the standard/pattern engine mounts are just too soft, particularly the front one- even the solid rubber one. Try a G60 front mount.

    Bax
     
  14. chrismc Forum Junkie

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    Apart from you SetGti...I really need to go to Specsavers [:$] [:$]

    Baxter, Your problem is also Overrun related IMO especially if you have replaced all the mounts/bushes. See my post above.. :)
     
  15. redbaron Forum Member

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    Sounds likely to me, it does hesitate loads if you blip the throttle quickly. What happens if i disconnect it then?
     

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