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12-18-2014, 11:52 AM | #1 |
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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Engine "surge" during constant speed
2009 Yaris 2 Dr. H/B automatic, 41,000kms (25,477 mi)
Have noticed that while driving at a constant speed at approx. 60-65kph (30-40mph) on a level road or slight downgrade with tranny in the "D" drive mode, that my tach will show revs approx. 1200-1500 RPM and then suddenly drop to 1000 RPM or slightly less, making the car "surge" like under engine-braking. I don't feel like I've backed off the throttle but revs climb back up again to original level once I do apply a bit more toe to the gas pedal. This happens intermittently and mostly if I am travelling along a long stretch of level road (or slight downgrade) at as I said, a constant speed. Car is a recently purchased Lease Return to replace my previous 2008 Yaris H/B 5-spd which I could no longer drive on account of a broken left leg ... which I was very happy with BTW ... All comments welcome and appreciated! |
12-18-2014, 12:34 PM | #2 |
It's the illusion you see
Drives: 07 Yaris Sedan Aero Join Date: Oct 2006
Location: Brossard, QC
Posts: 3,888
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The automatic gearbox will downshift on a downhill if you are slow enough to not stay in 4th. L
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12-19-2014, 06:10 AM | #3 |
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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OK ... that kinda makes sense to me ... though, my (ex) wife and I once each owned a couple of 2005 Toyota Echo's with auto-trannys that did not exhibit this behavior? ... But the Echo auto-boxes seemed slightly different with an O/D on/off switch on the side of the gear selection lever ... we always kept the O/D on.
BTW, if the Yaris auto-trans downshifts to 3rd on a downgrade because speed is not enough to stay in 4th, shouldn't the revs increase instead of suddenly decreasing? ... in a manual trans a downshift fr. 4th to 3rd at approx. 60kph would result in increased revs once the clutch is re-engaged ... Thanks for the reply! |
12-19-2014, 07:02 AM | #4 |
It's the illusion you see
Drives: 07 Yaris Sedan Aero Join Date: Oct 2006
Location: Brossard, QC
Posts: 3,888
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Yeah, I'm a bit intrigued by the losing rev part.
Does it do it on a flat surface too at the same speed? I wonder if it could be something about the pedal |
01-12-2015, 06:31 AM | #5 | |
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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Found this with a Google search;
Quote:
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01-12-2015, 08:51 AM | #6 |
It's the illusion you see
Drives: 07 Yaris Sedan Aero Join Date: Oct 2006
Location: Brossard, QC
Posts: 3,888
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^This doesn't apply in North America.
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01-12-2015, 11:09 AM | #7 |
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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Thanks for the heads-up ... autobox tranny does seem to exhibit the "hunting for the right gear" behavior from time-to-time though ...
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01-15-2015, 11:45 AM | #8 | ||
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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OK, found this on the Interweb ... Edmunds Discussion form about the Yaris auto-tranny. This quote describes 'zactly what I've experienced;
Quote:
http://forums.edmunds.com/discussion...roblem-a-lemon Some follow-up posts seem to indicate that the described condition is normal? Quote:
Last edited by John Lenin; 01-15-2015 at 11:47 AM. Reason: add content |
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01-15-2015, 02:10 PM | #9 |
It's the illusion you see
Drives: 07 Yaris Sedan Aero Join Date: Oct 2006
Location: Brossard, QC
Posts: 3,888
|
Decelerating on a downhill is not constant speed.
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01-16-2015, 10:34 AM | #10 |
Drives: 2009 Toyota Yaris 3-Dr HB Auto Join Date: Jul 2012
Location: Newfoundland
Posts: 20
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LOL! Obviously, deceleration is NOT constant speed!
Am curious to know if the operating conditions described in the Edmunds Forum for the Yaris P-R-N-D-3-2-L auto tranny are normal ... and if this "grade logic" referred to above is real or not? The auto trannys in both of the Echos I've owned in the past did not behave "oddly" whatsoever? |
08-05-2015, 10:45 AM | #11 |
maybe your oil is to "thick", or the valve timing controler selenoid is stuck?. Change the oil to the less viscous (eg. 5w-30) and cleand the valve timing selenoid thoroughly. You can use MAF cleaner.
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08-13-2015, 05:04 AM | #12 |
Drives: 2015 yaris le Join Date: Feb 2015
Location: hamilton, on
Posts: 149
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The yaris has somewhat of a naturally funky acting tranmission. We bought a lease return last year from a private dealer with around 122k, and I put around 30k on it. When cold, it takes a bit longer to shift to 3rd from second. Since it only has 4 gears, I assume that it could be causing somewhat of a problem. When I go uphill or downhill, I find myself jumping between 3 and 4 alot. I can even manually change it many times from 3 to 4.
A few months ago I did a drain and fill with full synthetic atf at around 50k. No difference, and there wasnt metal shavings or anything. I believe it's just the design. You shouldnt worry to much about it. If you get high or low revs, just give it a little more or less gas or change it manually |
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