Comfortmatic changing late in auto

Discussion in 'Tech/Mech General' started by CWH, Mar 21, 2015.

  1. CWH

    CWH Funster Life Member

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    Coming home from our trip last week it seemed as though the auto gearbox was late changing up (ie got to higher revs before it changed). This included on the flat. The 'up' function wasn't switched on.
    Could this be possible?
    If so, what - if anything - should we do about it?
     
  2. John Laidler

    John Laidler Funster

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    Have you tried pressing the UP button to check if it comes on and then press again so you know it should be off?
     
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  3. Lenny HB

    Lenny HB Funster

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    Just a thought, is the engine getting up to temperature as if cold may hold gears longer, never noticed it on my Comformatic but I've had cars where to box won't select top until fully warmed up, but that was on a conventional auto box.
     
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  4. CWH

    CWH Funster Life Member

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    @DevonBeekeeper yes we tried that, the indicator light came on/switched off so we assumed it was working OK. Could there be a fault here?
    @lennyhb good point but it continued for the 100 or so mile trip.
     
  5. mjltigger

    mjltigger Funster

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    Any chance you were heavier than normal or perhaps heavier footed?
     
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  6. CWH

    CWH Funster Life Member

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    @mjltigger what are you suggesting??? that we need to go on a diet??? (you could be right at that!) Actually no we were carrying less than usual and just trugging along at our normal 50mph or thereabouts, got the best average mpg to date as well despite no motorways.
     
  7. John Laidler

    John Laidler Funster

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    I'm out of ideas I'm afraid. Sounds like it needs a visit to somewhere where they can plug it in and check for any faults. You are supposed to check the gearbox oil level every 48,000 km although I don't know how easy that is to do! Might be worth checking as a low oil level could cause it to behave unusually.

    Otherwise just see what it is like the next time you take out.
     
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  8. CWH

    CWH Funster Life Member

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    Thanks DBK @DevonBeekeeper , at the time my first thought was the UP function, that's what it felt & sounded like, but as you say we'll see if it happens next time. We're nowhere near the 48000 km but I'll see if it can be looked at.
    Thank you guys for your thoughts & ideas.
     
  9. TheCaller

    TheCaller Funster

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    Can you tell any difference between driving with UP switched on & when it's switched off? If not, then despite the light going on & off, it sounds as if the gearbox itself is permanently operating with it on.

    Some people drive with it on all the time, so unless it's a result of a more serious underlying problem, it may not matter too much.
     
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  10. CWH

    CWH Funster Life Member

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    Can certainly tell on a good hill, though when we noticed the late change we tested on the next hill & Him Indoors (I wasn't driving) said it didn't seem to make much difference (though we were testing on a hill that wasn't much of a gradient); this was my thought though.
    That's interesting (& good!) to know.
     
  11. TheCaller

    TheCaller Funster

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    Oddly enough, it'll be easier to tell on a flat road.

    With it switched off, set off & accelerate with about half throttle. Note the revs as it changes up each gear.
    Then repeat with it switched on, trying to give it the same amount of throttle. If it changes up at the same revs (instead of higher), then it's probably stuck on.
     
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  12. CWH

    CWH Funster Life Member

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    Good plan @TheCaller , we'll give that a go next time out. Thanks.
     
  13. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    "got the best average mpg to date as well despite no motorways."

    From this one line comment I'd suggest leave it alone, its obviously working at its best, or at least close to it. Failing that if you really believe its not right then you have little option but to take it to a Fiat commercial specialist for diagnosis. With the best will in the world we are not going to be able to diagnose it by remote control.

    D.
     
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  14. Techno

    Techno Funster Life Member

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    If just chugging along at 50 it is no surprise that it is hesitant going to 6th in fact it's not a friendly speed to the computer at all. I always drive at 2000 rpm which will give 60-65 indicated on the flat to slight gradient.
     
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  15. CWH

    CWH Funster Life Member

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    Thanks Dave @dave newell lvs .
    Andy @Techno100 , it was ALL the gears not just 6th. It was also quite a wiggly road most of the way and single carriageway so a 50 limit for us.
    It just felt & sounded DIFFERENT from what it usually does.
    As long as there's not something obvious that we should/ shouldn't be doing, & the van's not going to take off into the middle of next week, I'm a happy bunny.
    [​IMG]
    I just love that you all will give your expertise so generously. It really is very much appreciated. :)
     
  16. Techno

    Techno Funster Life Member

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    I would take it that it is slow changing because you are driving so slow. When in the higher gears it will hold them for ages if light on the throttle but you need to be moving with intent before it will go into the higher gears in the first place. I don't think you have a fault.

    EDIT as you noted it needed higher revs to instigate a change
     
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