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Engine Hesitation (All makes/models)

Karen_CMKaren_CM Posts: 5,020
edited March 21 in Toyota
As this issue has become a question for debate with various makes/models, this topic will be devoted to any/all that may be experiencing this problem.

Community Manager If you have any questions or concerns about the Forums, send me an email, karen@edmunds.com, or click on my screen name to send a personal message.

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Comments

  • wwestwwest Posts: 10,706
    "Consumers don't always do (what's) best with the throttle..."

     

    With e-throttle " we gain better overall control..."

     

    "It also simplifies "shift-shock" control by letting the computer ease off the throttle for smooth automatic upshifts..."

     

    Statements by Paul Williamsen, curriculum development manager for Toyota Motor Sales USA.

     

    http://www.sae.org/automag/techbriefs/02-2002/index.htm

     

    (page down)

     

    Translation: You fools don't have any idea how to manage the throttle so we're taking over and doing it for you.

     

    Or:

     

    When we need to shift the transmission to hell with what the driver needs or wants, safety concerns be dammed, we'll dethrottle the engine until we can get the transmission into the proper gear and the clutches fully seated.
  • user777user777 Posts: 3,341
    is pretty good, showing a basic system overview. (context here, because the host dropped this new forum, somewhat out of the sky), is people complaining about hesitation on their Toyota Highlanders when slowing, then getting on the gas again.

      

    so after looking at that diagram in the link you provided, i reserve to theorize (its a free country) for these Toyotas, that *perhaps* some vehicles with the drive-by-wire implementation have a hysteresis, non-linearity or calibration issue in either the accelerator (pedal) position feedback, or the throttle position feedback sensors.

     

    if everyone has the same software and hardware, but only a percentage of people are reporting a problem, maybe they have a HW problem.

     

    if so, fixing a HW problem with SW would be interesting, yet one doesn't know the true root cause. maybe there is a SW programming issue which can be mitigated with a patch.

     

    oh nice. our cars are becomming more configurable and complicated as home and office computers.

     

    mechanics will have to have IT training (maybe they already do). ;)

     

    anyway (more context for others) its interesting to me that people are complaining on the Highlander, Camry, and Sienna Problem and Solutions forums about this hesitation.

     

    i wonder if it's a general design, implementation, software test, or parts supplier issue?

     

    is this a Lexus issue too?
  • pilot130pilot130 Posts: 319
    (1) That quote is taken out of context.

    (2) Its implied intent was not to show Toyota

     assumes drivers are fools or incompetent.

    (3) The article is three years old.

    (4) The article says their throttle by wire system was (in 2002) installed on Lexus LS430,Lexus ES300, and Camry. There have been few if any reports of hesitation on those models.

    (5) The article goes on to say that the same system has been used for three previous years on Supra,V8 Tundra, Land Cruiser, and LX430, with a low failure rate. There have been few if any reports of hesitation on those models in the 5 years the system has been in use.

     

    Wwest, your post underscores my previously expressed opinion on how the hesitation issue is being editorialized.
  • user777user777 Posts: 3,341
    i'm curious, how might you characterize the observations of the posters in the other forums? dismissable? unsubstantiated? suspect?
  • pilot130pilot130 Posts: 319
    Answer to your question? None of the above.

    I hadn't considered any sort of characterization of anyone's observations. Besides, wouldn't answering a question like yours depend on individual posts?

    Why would you ask such a question anyway?

    I'm simply looking for relevant facts and pertinent data, regardless of the source, which might help me (and perhaps others) understand this hesitation issue.

    That's all.

     

    For Wwest........

     

    I neglected to mention a couple of other facts from your link. It doesn't confirm Highlander's throttle by wire system is the same system referenced in the link, nor does it mention any tweaking, modifications, or improvements made to the system if it is used used in current HL models. I'm sure there would have been. Nevertheless, it doesn't shed much light on the present hestitation issue, but it it a very good explanation of how the earlier 2002 system operates.
  • user777user777 Posts: 3,341
    because you previously wrote:

    >>

    I don't think either one validates any theory, except that it does illustrate the principle that one can believe/quote anything one wants, but that doesn't always mean it's right, or accurate.

    It follows that principle could also apply to anecdotal reports in cartalk sites, agreed?

    >>

     

    So about those anecdotal reports of hesitation - they aren't right or accurate, or these people believe and quote what they want, or what?

     

    I assume you are keeping an open mind and giving them the benefit of the doubt that they are merely reporting what they experience.
  • pilot130pilot130 Posts: 319
    Definitely---keeping an open mind that is. Any further questions? If not, then I think it's a good idea to stick to issues, plus facts and relevant data pertaining to issues.

    BTW, my quote you referenced was about two totally contradictory newspaper articles/theories on the hesitation issue. One said one thing, and the other said exactly the opposite. My point was "which one is right"? My opinion was I didn't have a lot of faith in either one, and quoting one or the other as validation of either theory made little sense.
  • wwestwwest Posts: 10,706
    would make anyone assume that the Toyota hardware and/or firmware/software designed for E-throttle in 2002 isn't still in use today?

     

    And I have never theorized that the hesitation problem exists on anything but FWD, or front torque biased AWD.

     

    And please look more carefully at just what Williansen said.

     

    Paraphased:

     

    When the transmission ECU determines a need to "upshift" and the driver has the throttle position too high for a smooth shift sequence, the ECU will over-ride the driver's input and ease off the throttle postion until the upshift is completed.

     

    And if you think that there are no hesitation complaints about the ES300 or Camry you need to take a closer look.
  • wwestwwest Posts: 10,706
    Pilot is correct, the software/firmware descibed by Williamsen and designed/written in 2002 is no longer in use.

     

    It is highly likely that the software core, base template, is still in use, but like almost all(exception being that in "Legacy" uses) software, it continually evolves, expands.

     

    Apparently the original 2002 software design only eased-off the throttle for upshifts. at least that's all that can be stated factually.

     

    The newer versions obviously have the added, evolutionary, capability to help prevent loss of directional control of FWD (or...AWD,) on a slippery roadbed surface. While at the same time still retaining the earlier capability of preventing premature failure of the transmission by easing off the throttle until the transmission clutches are softly and smoothly seated.
  • pilot130pilot130 Posts: 319
    (1) I believe I said that *if* the 2002 version of Toyota's TBW system was still in use, there would likely have been any number of engineering changes over three years--i.e., it can't be concluded that the current system is identical to the 2002 version.

    (2)There really aren't that many posted complaints with ES300's or Camry's in the 02 vintage--and I believe I did say "a few". Even later vintages of similar models aren't being overwhelmed with hesitation complaints.

    The issue of"Hesitation" doesn't rate even honorable mention in most mass media Consumer Satisfaction Polls for those models, where very large owner cross sections are tabulated.

    The same applies to LS 430's, Supra's, V8 Tundra's, Land Cruiser's, LX 430's---not much joy there either.

    (3)I have no issues with what Willianson said; in my post I addressed what *wasn't* mentioned in your editorialized comments included with the link.
  • wwestwwest Posts: 10,706
    Did the Camry or ES300 have e-throttle prior to 04? If not I wouldn't expect to see hesitation complaints prior to 04.
  • pilot130pilot130 Posts: 319
    Quotes from your link, Wwest, (2002 News Article):

    "Toyota developed an all-electric throttle-by-wire system for its Lexus LS430 luxury flagship that it has also deployed in its near-luxury ES300 and mainstream Camry family sedan."

     

    Continued later in the article: "Earlier Toyota systems used a conventional cable as backup, but under normal conditions throttle position was handled electronically. Several years of experience with that system on the Toyota Supra, V8-equipped Tundra, Land Cruiser, and LX430 models emboldened Toyota to eliminate the cable. 'After a number of years of offering this, we've got the data on what the failure rate is,' said Williamsen. 'It is pretty low'."

     
    I didn't look thru entire forums, but there apparently are very few hesitation issues raised for any of these models.
  • user777user777 Posts: 3,341
    maybe because they aren't structured to solicit that information...

     

    come on. you're an engineer.

     

    what can you definitely conclude based on a limited number of anecdotal reports found in some e-forums?

     

    you want facts and objective quantitative information...but you're not likely to acquire either of the quality you desire in an e-forum or a Consumer Satisfaction Poll.

     

    you know that there are a number of people that use a high-tech artifact, and assume it is their fault for not operating it properly when it doesn't work.

     

    how could they possibly know for example the designer's model of the artifact, when all they have are the affordances and observables to form an incomplete user's model? granted there is the owner's model - but that is going to be short on technical detail and for a reason. the user shouldnt have to know how the system is implemented. it should work, and to a good extent the way they would expect it to.

     

    ..by which in this context i mean - how does one expect users experiencing the hesitation to formulate a designer's model of what is going on when all they have is the pedal, the sound and speed of the vehicle, what they feel in the seat... they are not designers. they are users without that information at their disposal.
  • pilot130pilot130 Posts: 319
    There is no "one size fits all" answer to your question. I avoid giving rhetorical answers to rhetorical questions. I try not to ask them either.
  • wwestwwest Posts: 10,706
    Was it then the advent, introduction, of the more powerful 3.3L V6 that that led to the "hesitation" change in the tramsmission ECU firmware?
  • I did a search today using "Toyota Highlander" and "hesitation" as key words, and I tried to eliminate general use of the latter by eliminating hits with the phrases "no hesitation," "without hesitation," "any hesitation," etc. I also tried to eliminate references to hesitation problems among other makes and models. (Like the 2004 Subaru Outback wagon I test drove.)

     

    The approach is admittedly not perfect. I ended up with 210 hits, but the search engine then reduced the number automatically to 107 hits by eliminating urls that were sub-categories of the urls left in the list. (Such as numerous mentions of the same basic edumunds site.) Of course, my parameters may also have eliminated a number of other hits that actually did discuss the Highlander problem. So someone with a lot of time in his/her hands may want to repeat the search using fewer restrictions, and then go into each link to see if it applies.

     

    Of the 107 hits I ended up with, there were maybe 50 that actually dealt with the hesitation problem that Highlander owners have been discussing. Two were in newspaper articles, and the rest in various forums. The earliest complaint about the hesitation problem that I found was in a competing forum and was dated November 24, 2001.

     

    Maybe these results are not overwhelming, but it does appear that many people are talking about the issue in many places, not just in edmunds. I suspect that there soon will be more discussions about the hesitating Highlanders in additional newspaper and magazine articles. While I don't have the problem (I have a 4-cylinder Highlander), there is enough evidence out there for me to believe that the hesitation issue is real. I would hope this new discussion thread can help determine the source of the problem, identify why some people have it and others cannot replicate it no matter how hard they try, and inspire the car manufacturers to work quickly to find a resolution.

     

    Toward this end I think it would help if all posts include 5 pieces of information: (1) Make of vehicle, (2) type of engine, (3) FWD or AWD, (4) type of transmission, and (5) hesitation experienced or not experienced.
  • user777user777 Posts: 3,341
    is it relatively easy to augment the search to include the Sienna and the Camry, which are other vehicles people have reported hesitation on Edmunds?
  • It's pretty cumbersome to augment or narrow the search to get at the specific information we are after due to how the search engines are set up. I started out by using simply "Toyota Highlander" and "hesitation" as key words, and I got close to 800 hits. Some of those actually were talking about the hesitation problem in other Toyota vehicles, including the Sienna and various pick-up trucks. I didn't see any that discussed the Camry, but that's probably because I wasn't looking for Camry information.

     

    I know there is some hesitation at times with the 2004 4-cylinder Subaru outback because I experienced it and because a friend with Subarus said "Yeah, they do that." When I was looking at vehicles early in 2004 there was no mention of hesitation on the Subaru forum that I recall, but also nothing in the Highlander forums at that time. When I have the chance I think I'll go back into the Subaru forum and see if it's a topic of conversation there. Or are any Subaru owners reading this who could save me the trouble?
  • user777user777 Posts: 3,341
    gotcha. in this case, i presumed people would be interested in hesitation on vehicles with drive-by-wire or e-throttle systems...then again - that's rather short-sited on my part.

     

    i'm sure there are numerous means that result in engine hesitation in a vehicle with a conventional cable-throttle.

     

    probably, KarenS, the host expected the discussion to be open to accomodate all sources.
  • wwestwwest Posts: 10,706
    I ordered the six speed manual with my throttle-by-wire 2001 911/996 C4. No firmware GREMLINS in my gearbox!

     

    But them again it is most definitely rear torque biased!

     

    But then maybe that's because the weight of the engine is also at the rear.
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