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08-24-2007, 05:02 PM | #1 |
Drives: 4x4 EGG Join Date: Aug 2007
Location: Boostville, NY
Posts: 14
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Automatic owners, rough downshifts?
I havent had my Yaris long, and cant complain about anything except one thing in particular. With the automatic transmission, sometimes when coasting (especially noticable on downhill/declines) the transmission likes to downshift at seemingly odd times. I notice a lot of the time it will happen while coasting downhill and I very lightly begin to tap the brake. Its almost as if as soon as I touch the pedal, the transmission will drop a gear, thinking I am slowing down or coming to a stop even though I havent slowed down much, if at all. This results in the RPM coming up a lot higher than they normally would be while driving at that speed (not so much so that its banging off the rev limiter or anything, but its noticable). Anyone else experience something like this?
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08-24-2007, 05:31 PM | #2 |
Drives: Sc'd Yaris Sedan. Join Date: May 2007
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Yeah it's a fuel saving thing or something. Been discussed. Try searching. :)
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08-24-2007, 05:47 PM | #3 |
Drives: 4x4 EGG Join Date: Aug 2007
Location: Boostville, NY
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pretty sure this isnt related to fuel saving. how is it saving fuel if I touch the brake and it revs to the moon?
Im not talking about the noticable "on/off" feeling you get with very light throttle input with the drive by wire system...
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Garage: '00 Phoenix Yellow Integra Type R Turbo '07 White Nismo 350Z '07 Yaris LB |
08-24-2007, 06:42 PM | #4 |
Drives: 2007 Yaris Sedan "D" package Join Date: May 2006
Location: Barrie, ontario
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well sounds like your a "know it all", so go away...
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08-24-2007, 07:42 PM | #5 |
Lonesome Cowboy
Drives: 2007 WHITE HATCHBACK Join Date: Feb 2007
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.................."revs to the moon"
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08-24-2007, 07:46 PM | #6 |
好多人&
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Here's a "fix" if you want to coast down the hill. Flick it to N and the back into D quickly (EDIT: should read shift from D to 3 and back again quickly). It'd shift back up. It's just downshifting because obviously the automatic transmission can't read your mind and doesn't have eyes. It happens to all new electronic controlled transmission coming out. Just to help control/maintain the speed as opposed to coasting freely down a hill... more so safety related than anything else.
It is saving fuel because your engine will not use fuel to keep it running. The momentum you have going down the hill is sufficient for the engine to keep spinning at high revs without fuel. Next time you drive a car with an instantaneous fuel consumption gauge on it, try it. It'd read 0.0L/100km. (or 99.9MPG in your case). Last edited by SmellyTofu; 08-25-2007 at 07:54 AM. |
08-24-2007, 09:09 PM | #7 |
vroom vroom
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08-24-2007, 09:19 PM | #8 |
Drives: 4x4 EGG Join Date: Aug 2007
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for you slow people, keyword ROUGH downshifts.
etimago, thanks for the link. I understand the concept of DFCO, Im just curious if its doing so a little more roughly than normal. Sometimes its a pretty solid surge and not consistent so it doesnt feel right. I was curious if anyone elses was "revving to the moon" like mine.
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08-24-2007, 09:34 PM | #9 |
vroom vroom
Drives: lil red 5-door Join Date: Sep 2006
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Well I can't be exactly sure for the automatic, but I know in mine you can feel a bit a a jerk as the DFCO is activated.
But I think SmellyTofu is right in saying that this is just the way the auto transmission works. It's a pretty clever system but it has its limitations.
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The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson Bye bye 1NZ... |
08-24-2007, 09:41 PM | #10 | |
Lonesome Cowboy
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Quote:
tee hee hee
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08-24-2007, 10:25 PM | #11 |
Clean and (dis)Functional
Drives: Yaris 2dr--Black Betty Join Date: Mar 2007
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I manually shift down sometimes to assure DFCO kicks in....which IMO is sometimes rougher than what you're talking about (the ECU doing it). I do it manually because the ECU version requires the proper circumstances, and is a little more erratic. Try a none DFCO car....shift down with you foot off the accelerator, it will probably be rough too.
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08-25-2007, 12:52 AM | #12 |
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What exactly doe's "to the moon" mean? Do you have an RPM gauge? Yes, it is normal for the auto to downshift on a hill if you touch the brake, but a single gear downshift hardly revs the engine to the moon. Unless yours is defective and downshifting harsher than normal, it's normal and nothing to worry about.
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08-25-2007, 07:59 AM | #13 | |
好多人&
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Quote:
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08-25-2007, 10:10 AM | #14 | |
I love my Yaris!
Drives: White Yaris Liftback 2 Dr. AT Join Date: Sep 2006
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Quote:
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08-25-2007, 10:52 PM | #15 |
Drives: 08 Yaris 5-speed Join Date: Jul 2007
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Wow.. I feel like a nub. I never knew about DFCO, and I'd like to think I'm pretty car savvy. This also makes me feel dumb for leaving my car in neutral while decelerating; it sounds like it'd actually be more fuel efficient to leave it in gear. Learn something new every day.
That said, get a manual tranny! lol |
08-27-2007, 09:45 AM | #16 |
Insert sarcasm here.
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I know exactly what you're talking about. The 40-50mph down shift that sometimes hits pretty hard if you take your foot off of the gas, and you can hear the engine rev pretty high on the down shift. It can be a bit annoying, and part of the reason why I hate auto transmissions.
I don't know if it's DFCO though or just really hard downshifting. |
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