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accelerator response lag..

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

  1. jayadev

    jayadev Esperto

    Messages:
    1,057
    Kannur, India
    Kannur
    Grande Punto 1.3 90 HP
    i may sound wierd or strange but this is my observation . this is how i could express ..pardon me for my poor linguistic abilities i have written this long ago in drafts, posting it today.

    nowadays while i tap accel pedal i find a lag before engine revv up. the lag should be just couple of milli seconds .so i dont see that instant rush in engine moment i press the accelerator .

    i repeat the lag should be in milli seconds it is just felt, nothing for any worries for me yet engine, power, torque and everything is perfect .

    why am i concerned : that lag has eaten up the original instantaneous response thing which i used to enjoy in my mjd mill .i had driven couple of other diesal engines some of them are just perfect but some did show similar lag .

    i remember i once had short test in linea t-jet (though petrol ) response from engine moment you touch pedal was ausummm, quick like electricity.

    i would hate to hear that i need to live with it.
    but would love to note that other members do share this observation and their is a cure.

    hope i am not sounding lunatic...:p
    Last edited: May 13, 2011
  2. jumu

    jumu Superiore

    Messages:
    969
    Chennai
    Jayadev, your car must be gasping for air. If it is a new symptom, then try cleaning the air filter and also check the fuel filter for any clog and also quality of fuel you have been filling lately. Maybe you should check out another filling station. Rule out simple possibilities before you diagnose further

    Abdul

    Y
  3. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    Accelerator response in a diesel will always be slower than a petrol, in general.
    So it would serve you well by not comparing the t-jet with the MJD .

    Also, the off-boost response is nothing to write home about in the 90bhp mjd. Cant comment on the 75bhp mill.

    Do the checks as outlined by jumu, especially the air filter. Blow some pressurised air through it. The fuel filter can be left unchecked.

    As for curing/improving pedal response, there can be many ways, but for an average user like us, not worthwhile.

    Gurjinder.
  4. amogh

    amogh Staff Member Janitor

    Messages:
    1,377
    Pune
    Grande Punto 1.3
    +1 to jumu and gurjinder

    on most occassions the importance of having a clean air filter is neglected. I have seen many feel "great" about their car after the free check up camps. All that is done during the camp is clean the air filter !!

    T-Jet quick like electricity : That's a first !!
  5. ratanshivi

    ratanshivi Regolare

    Messages:
    254
    Mald (East)
    Hey, Irrespective of Diesel or Petrol - punto's are drive by wire and thats the basic reason there is a lag, so we have to live with it tilll u posses the car. Yes cleaning the filter makes a difference.

    Though for a peddle pusher like me I hate this one thing about this car. There r times when i needed the response nd did not get it,frustrates me so much that I could get out of my car and burn it!!
  6. johnny

    johnny Regolare

    Messages:
    437
    Greater Noida
    Greater Noida
    Grande Punto 1.3
    +1 to ratanshivi. Though it is not "drive by wire". It is only "throttle by wire". Because of this the ECU may curtail the throttle response at times, based on the "driving conditions".

    Johnny
  7. gurjinder

    gurjinder Staff Member Janitor

    Messages:
    3,989
    Punjab
    @johnny and ratanshivi

    It is drive-by-wire.

    And these systems are the fastest methods of giving accelerator inputs than the erstwhile cable linkages. The drive-by-wire replaced the traditional cable linkages for a reason : better and more accurate control over the inputs, thereby resulting in increased performance and efficiency. And it'll be a fallacy to assume that the electronics are slower than the cable linked throttle.

    Cables linkages, over use can get stretched and worn out and lead to incorrect inputs. Drive by wire will not.

    Here's an example - The Lexus LF-A has a 4800cc V10, and a drive by wire throttle. Yet it can reach its redline from idling in a mere 0.6 seconds. Yes, that fast. ( Not only because of drive-by-wire , but its one of the reasons)

    So, it will not be right to say that drive-by-wire makes the response slower. There are other variables - whether you're in the powerband or not, whether the turbo is spooled up or not etc.

    Cheers!

    Gurjinder.
    Last edited: May 13, 2011
  8. Hey guys, I am a laymen in automobile knowledge. I have a punto mjd brought on september 2010, does this also have drive by wire? i dont see it mentioned in the user manual though.
  9. jayadev

    jayadev Esperto

    Messages:
    1,057
    Kannur, India
    Kannur
    Grande Punto 1.3 90 HP
    yes i understand that due to many reasons.
    but at younger stage the same mill was much more lively. that is where i am suspicious

    let me say, it is not air filter.
    i have taken out filter and checked it. i clean my filter every 1000km it is as much easy a task for me so i do it.

    +1

    look at the pivot of accelerator pedal, it is something like an electronic volume controller .

    question:

    there exist rev limiter at 5100rpm needle doesn't go beyond that.

    does the car have speed limiter (P90hp)?
  10. pioneeraaron

    pioneeraaron Superiore

    Messages:
    716
    Mulund/Mumbai
    @jayadev

    even im facing this lag buddy and learnt to live with it..i own a FIRE..the accelarator lag is more in a FIRE engine..to an extent the engine gasps for air..cleaning the filter helps a lot but conditions get back to zero very quick :thumbs down

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