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accelerator response lag..

Discussion in 'Engine Compartment' started by jayadev, May 13, 2011.

  1. johnny

    johnny Regolare

    Messages:
    437
    Greater Noida
    Greater Noida
    Grande Punto 1.3
    @gurjinder

    "Drive by wire" is a term that includes technologies like "throttle by wire", "brake by wire", & even "steering by wire". There is a lot of material on the net on this subject.

    What we have in the Punto/Linea is only 'throttle by wire'.

    What you have explained about how the system works is correct. The system will ensure that at all times, the fuel input to the engine is maintained at optimum conditions. As you have also brought out:

    "There are other variables - whether you're in the powerband or not, whether the turbo is spooled up or not etc."

    Because of these factors, at times the engine may not respond immediately to your throttle inputs. While this may be perceived as a lag, it is not because the electronics are slow, but it is because the electronics are ensuring that you are operating the engine optimally.

    Lastly, I have done a lot of flying on the Mirage 2000 which has a quadruple redundant digital "Fly by wire" system. It is a very interesting subject, and if we ever meet, we can discuss the subject at length.

    Regards
    Johnny
  2. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    OT

    It'll be an honour to.

    Gurjinder.
  3. clash81

    clash81 Regolare

    Messages:
    398
    Bangalore
    I find that there is a super lag in my new 90hp vehicle. I am getting used to it. I dont think there could be an issue with the air filter already.
  4. jumu

    jumu Superiore

    Messages:
    969
    Chennai
    When Jayadev complains, its in comparison to what he was experiencing before, so asking him to live with it is not ideal. Maybe something is amiss and it irritates an enthusiast when that happens. It could be a variable like fuel, air or fuel filters. I would advise jayadev to take the car revs to the limit in driving , You can do it ideally in 2nd gear at lesser speeds. A bit of thrashing that way may lead it to correct itself. No jokes, many problems get resolved that way !!:)
  5. jayadev

    jayadev Esperto

    Messages:
    1,057
    Kannur, India
    Kannur
    Grande Punto 1.3 90 HP
    i want to make sure that we are not talking about turbo lag which is unavoidable.

    right to the point.
    unfortunately thrashing din't help i tried couple of time.

    i myself very much feel something amiss or resultant of ageing but my car ain't old enough its just 8200+km.

    as said before fuel filters or bad quality fuel is next subject of doubt, if there is no electronics or mechanical issues know so far concerning the same.
  6. eldrid

    eldrid Amatore

    Messages:
    68
    London, United Kingdom
    London, United Kingdom
    Grande Punto 1.4
    Hey guys, i experience the same. only mine is mostly when in 1st gear..that too only at low revs for a few moments.
  7. karan desai

    karan desai Superiore

    Messages:
    805
    Morbi, Gujrat
    lag is experienced by every fiat owner. they have tuned the ecu like that. its not that the engine is not responsive, but the ecu makes the acceleration a bit dull to achieve better fuel eco figure which were bad in the palio era. palio was more fun to drive. one just have to adjust and stay in the power band and then no problem at all. keep the rpms at around 1800 and see the response from there. again if you floor your pedal the ecu will cut off fuel supply and you will feel no response from the accelerator.
  8. jayadev

    jayadev Esperto

    Messages:
    1,057
    Kannur, India
    Kannur
    Grande Punto 1.3 90 HP
    karan,
    but it was just great in beginning ,say 2-3k kms . though it is not awfully lazy but i do feel the prick.
  9. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    That is not the ECU cutting off fuel supply. It happens because the engine is not designed to handle such an enormous accelerator input instantly, and it may sputter or not increase revs because it'll be unable to. These are tuned-and built-for-economy engines that we have in our cars.

    If you gradually increase the accelerator input to the max, you'll be able to take the engine to the max. It is at the redline that most ECU's are programmed to cut off fuel supply to prevent over-revving of the engine.

    Gurjinder.
  10. Chaos

    Chaos Regolare

    Solution.

    AFAIK, there is NOTHING wrong with your car!!

    This throttle response was the first thing that caught my attention when i was new to my 1.4 Punto. after driving a cable accelerator on the Indica Turbo.

    There is a trick to it. Teach your ECU.
    just tap the accelerator a few times (in neutral) and you will notice the difference looking at the rpm needle (and the engine sound).
    just press the pedal ~20% and quickly release it, and once the rpm starts falling down press again. Just rev till 1500 - 1800 mark not more.
    do this like 4 times and you should see the difference in the response.:cool:

    Ratan hardly faces this "lag" issue coz of his driving style:mrgreen:. apart from the electronic lag (this will always be there)

    Think of it like sports mode or something.
    If you start driving very sedately for some time, the ECU learns your style and uses less fuel. The main aim of the ECU.
    you go for performance it will give you performance. (takes time to learn)

    It use to happen a lot with me, petrol costly, so saving fuel = sedate driving. But when I needed that performance in traffic, no matter how much quickly and deep I pressed the pedal, the car would not deliver the power quick; same slow pick up. But after some fast driving the response would be that what i wanted.. its like the punto has 2 sides to it.

    Year back, andy did bring up this issue.. it was solved with the above steps..
    Rahul & neehal both own Lineas, they also agree with the 2 sides to the throttle response.

    try it::T

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