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Engine Hesitation (All makes/models)
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Comments
Many of the electronic devices that I use everyday, occasionally need to be "reset" from time to time. Example - I have a cable modem, and a router. The other day, internet access just quite. I called the cable company's tech support, and we went thru all the devices settings and... we ended up doing a "power-cycle reset" for all the devices; after which, everything worked fine. All that's required is to disconnect form power for 30 seconds (some other devices might take longer, but this worked for my purposes). Then re-connect.
Now that you've documented the problems with the dealer, if it were my car, I'd find out if there's any reset codes for the radio or anything else, write down my radio station pre-sets, and disconnect the battery for 10 minutes for a full ECU reset. Then see how she drives. I'm surprised the dealer didn't try this. This is the autocrossers's trick to reset the ECU for premium fuel and shift quality, just before a timed run. And it worked once for me in an admittedly older Chrysler that had transmission shifting problems.
Whatever happens, you have my best wishes.
BTW - if it were my car, I'd have done the exact same by waving the "reset" which was encouraged onto you...
you've clearly experienced worse behavior after they've done that once, AND, you want to have a reproducable issue for the district manager or anyone else they send your way.
yes.
i don't know how people conclude there's anything "normal" about what your experiencing, (maybe they mean, the behavior is inexplicable on other vehicles they've seen?...that's not what I'd label "normal", rather if its seen on other vehicles that's what I might label "common")
and with all due respect to another poster that thinks a "reset" is in order, your lexus isn't a router, and they aren't trying particularly hard to understand the problem by suggesting it.
resetting electronics is arguably one of the surest ways NOT to get at true root cause, enlightenment, or solution.
AAAWORLD.COM
January/February 2005
Snake Oil by Peter Bohr
Corporate Average Fuel Economy, CAFE for short, a US law that requires automakers to build vehicles that meet certain standards. Automakers are desparate to meet them, or they have to pay millions in penalties.
{Hmmm....
MILLIONS IN PENALTIES....$$$$.}
Meeting CAFE standards might be a cinch if Americans favored little gas misers. But we don't; the ten most fuel efficient cars account for just 1 percent of total cars sales. Moreover, automakers are thrilled to indulge our taste for BIG IRON. Were it not for high-profit---but often, thirsty-, SUVs and pickups, some automakers would have pretty bleak balance sheets.
Roger Clark, a senior manager at General Motor's Tech Center...."We scour the Earth for ways to save gasoline." "Eager to have their cake (avoid CAFE penalties) and eat it too (sell highly profitable vehicles), GM and other automakers employ thousands of engineers to devise and evaluate fuel-saving possibilities."
Paul Williamsen, Toyota executive, speaking of cheap gizmos advertised on TV to improve fuel ecnomy....."We'd use any inexpensive device--we'd use it even if it were expensive. The grief our engineers go to in order to save a mile per gallon would blow you away!"
After a friend loaned me his Prius for a week, in return for his having my Porsche, I went out and bought a 2003 model. The Prius has a control function that allows you to set a mode wherein actual engine compression braking is used when you let off the gas, during coastdown. There is a note of caution concerning use of this function that says that fuel economy will suffer...
The Prius normally uses regenerative braking to simulate, give the feel of, engine compression braking. So, use engine compression braking, but when you do your batteries don't get charged.
From this all blessing (engine hesitation symptoms) flow.
The next time you're out cruising in your Sienna, say at about 65MPH, let off the gas completely and time how long it takes to coast down to say 40MPH. Now repeat that but pull the shifter down into 1st. See how much quicker you get down to 40MPH?
All Toyota is trying to do is save you a bit of pocket change.
Anytime you touch the brakes, the presumption being that the throttle valve is fully closed, why shouldn't the transmission be "upshifted" via unlocking the torque converter, slightly reducing engine compression braking. Even if you only release the gas pedal, why shouldn't the transmission be upshifted to extend your fuel mileage?
So what if you suddenly change your mind and decide to accelerate quickly? Your transmission now has a mind of its own and at this particular moment it wants to go in the other direction. Guess who wins, EVERY TIME!
Sorta like a two-headed snake....
What, how much, positive effect do you suppose this might have had on Toyota's CAFE with the hundreds of thousands of vehicles, Camry, Solara, ES330, HL, RX300, RX330, etc, sold since they started (2000?, 2001??) the upshift program?
How much, do you suppose, that would add up to in CAFE penalties should Toyota agree to fix each and every vehicle shipped using this technique?
I have inserted my own wording "()" because that's the way many of us hear such statements.
For the record, now that's it's working, I don't care what was wrong with my router/cable modem. It's worked flawlessly since that time. And if it screws up, I'll reset them again. Sure, not the same thing as a car; but it has firmware and software, just like the Lexus' ECU. Haven't you ever re-booted your computer to clear a problem?
No one is advocating letting Toyota off the hook here - Josh5 is to be congratulated - I did, and so did you. It almost sound like you're afraid the reset might work, and we all might miss out on a chance to get to the "root cause" of this issue. But since Toyota is already working on a fix, from Josh5's and previous owner's vehicles; and since Josh5 is a fully documented case, then he'll get the fix when it becomes available. Meantime, let's not make him continue to suffer if there is a way to not compromise his safety and the safety of others.
I think it has more to do with the "maximizing of traction issue" that's been proffered earlier. I've drive cars on ice before, and a sudden lift-off can cause a traction loss at the drive wheels.
I did enjoy the post about GM's thousands of engineers working of fuel economy. I wonder how many of them worked on the H2?
I get your point. Others may try it. They shouldn't ever try it.
Even the ones you can operate "manually" will not downshift if the result would overspeed the engine or damage the transmission.
But I would advise that no one do this unless you're absolutely certain of a dry roadbed and no vehicles close behind.
But this forum and others seem to have a clear majority that do not like such things being said about their FWD or..., vehicles.
obviously, he'd be driving it at risk wouldn't he if he left the vehicle in its current state? his dealership didn't seem overly concerned though did they?
i wonder what their liability on the matter is.
his car is demonstrating that it is not operating properly. it seems from his description, it may be worse than some other reports posted and, who knows, may involve some other issues too.
if *he* resets it though (your suggestion - and i think a poor idea), or has the dealership reset it (not great - but better that a DIY operation - and it's documented - very important), he looses the only thing he's got when pressing the point:
leverage
by virtue of the fact he can demonstrate it at will for anyone (technician/mechanic to dealership management, to district/region manager/rep to factory customer rep to factory engineer to corporate).
if it were my car and really bad, i'd probably be driving another car during the period i was expecting the company to respond to my complaint.
why aren't they (i'm thinking the dealership) asking to take his car off his hands so they can put it under some road testing, or why isn't the factory asking for it so they can do some lab testing of the electronics and associated software, or so that they might tear it down to inspect the mechanicals?
hmmmm. do they know enough about the problem already so that's not necessary?
ok, so let's say he resets it and it's temporarily better - sure it's better for his family's safety - no argument with you there. he's got to make a judgement call, doesn't he?
i'm not advocating he drives unsafe.
naw - i'm not afraid it will fix his problem. ask yourself this: if that was a fix, wouldn't they have offered that to him right up front? wouldn't they be pulling that operation on all the cars with the issue? i mean, is that what they are actually doing and is it successful?
i said, a lexus isn't a router. it might have a lot of computer electronics, but the vehicle wasn't designed to require hard-reboots periodically to function to specification. i presume neither was your router (that is unless it was cheaply designed and engineered). my router wasn't designed this way - but that's for another forum.
yes, i use a computer at work, and yes, i've rebooted it on occasion to restore its operation. but, a personal computer is a much more complicated, non-homogenious, and uncontrolled computational environment as compared to an ECU/TCU running a real-time embedded operating system with a very limited, probably fixed (and small) number of tasks in a very optimized and constrained manner.
that said, it wouldn't surprise me that if the ECU/TCU self-detects some exception, one example via a watchdog timer safety feature (say it failed to finish a computing task in a prescribed amount of time); under that scenario, it might be desined so it soft-reboots itself (to some more or lesser extent) and starts over after throwing an exception traceable to the outside world...so it keeps functioning rather than "a blue-screen of death" in the middle of the intersection.
How in Hades is this thing going to figure out which one of us is in the driver's seat at any given time?
NO WAY! NOT!
But here's one I will buy into. After "rebooting", it takes awhile for the various ECU to "learn" the charactoristics, "calibration points, curves," of all the sensors and servomotor feedback devices.
For instance, when I disconnect the battery in my 911/996 the system must "learn" where the end travel for the windows is. Just as you often have to retrain the sunroof so it will know the difference between pinching fingers or its end travel.
In the case at hand after the system is reset how does the engine ecu know when the gas pedal is fully released?
A short story, if I may.
About two years ago TeamSeattle ran two new Saleen SR7s at the 24 hours of Daytona. About an hour before the race one of the cars was finally put back together enough that the engine could be started.
WOW! WOT, the noise was deafening!
The mechanics forgot that with the battery disconnected the ECU "forgot" where the end travels of the DBW/e-throttle was.
Picture this, a Saleen rep, white shirt and tie, standing over the engine (ignition off), one foot resting on each exhaust manifold, using a laptop computer resting on the top of the cab, to "train" the ECU where the end travels, off vs WOT for the gas pedal, and the corresponding end travels of the engine air intake servomotor, closed vs WOT.
So, when you "reset" the engine ECU how soon does it "learn" the gas Pedal's fully released, "throttle fully closed", command position?
Until it "learns" the gas pedal's fully released position it cannot execute the "upshift" software/firmware routine.
And that might be a matter of several days.
And for those of you that don't want to buy into my "theory" just find some way to block the gas pedal partially, slightly, open, such that when fully released it can never return to the factory position, and then do the reset.
You will find that the ECU has "recalibrated" and now accepts the new partially open position as the fully closed position.
Thanks everyone for your conern and responses to my post #100.
I'm sorry there was some confusion about whether or not I reset my ECU, but I said the following in the post #100:
"He then offered to reset my ECU which I refused. They did it the first time I took the car in, and the vehicle was even less responsive than now."
Specifically, the first time I took the car in for transmission problems, the dealer reset the ECU and it made the problems more pronounced. This is why I did not want them to reset the ECU the second time I brought it in. It did not fix anything.
The point made about multiple drivers using the vehicle is excellent. Yes, how does the vehicle decern between drivers?
Answer:
It doesn't...right away. The shop foreman at my dealership said it takes 1000 miles for the RX 330 to adapt to a driver. However, why should my girlfriend (for example) have to drive a car that's adapted to my driving style? Does that make it unsafe for her to drive? Perhaps, being that it is now unpredictable for her.
Okay, now here's what's going on with Lexus corporate. First, they did not return my call by 10am this morning, so I called them at their customer service number. I spoke with a woman who said my case had been forwarded to a supervisor who was going to contact my dealer and get back to me within 2 business days, but that I should hear back today. When I returned home from work there was this message on my machine:
Names and phone numbers have been omitted.
"Hi Mr. (my surname), this is (female) calling from Lexus headquarters. Um, I was calling to let you know I am gonna work with (dealer) Lexus in regards to your request. And, um, once I hear back from them, I will contact you. If you have any questions, my number is (800)xxx-xxxx. Thank you."
So that is all for now. We'll see what happens.
Remember back when automotive salespersons and "car people" were telling us that ABS would help us stop quicker, shorter, and faster?
Totally wrong, TOTALLY.
So what I think is that the manufacturers have told the sales folks that it takes up to a thousand miles for the various ECUs to "adjust", learn, calibrate the various sensor and servomotor parameters.
If the car were going to "learn" my driving style within the first thousand miles (during break-in??)I'm quite sure there would be caution note in the owners manual to be careful and not confuse the poor thing by switching drivers....
however, the system's behaviors couldn't be that radically different from driver to driver such that when one driver borrowed the other driver's key-chain, the car ran in a bizzare manner...like gross hesitation or shifting.
that would be a bad design.
I do hope Toyota responds to this issue quickly - I just bought a 2002 Highlander, with a 4 cyl, 4-speed auto - largely due to this Forum. I might well have popped for the new 2005 V-6 5-speed auto I test drove last month had I not been keeping up here. Maybe next time. And maybe they'll put that new 2.7 Liter Tacoma motor in it next year...
1. Extend the fuel economy by significantly lowering vehicle "drag" from engine compression braking. Anytime the throttle is fully closed the transmission is automatically upshifted to lower engine compression braking.
2. Significantly reduce the danger of loss of control of FWD, or front torque biased AWD, on slippery roadbed surfaces by reducing engine compression braking.
3. Significantly extend the useful life of the transmission by reducing its "workload" from engine compression braking. Many of these vehicles were shipped from the factory with a transmission fluid life expectency of that of the vehicle itself.
Keep in mind that by the year 2000 the analog, fluid based, "computers" previously used to control automatic transmissions were virtually PERFECT in their overall control operation.
Toyota's electronically controlled transmissions represented a totally new, clean sheet, design.
So, the transmission ECU firmware, software, detects that the vehicle is in a "coastdown" mode, throttle fully closed, and accordingly begins an "upshift" gear change sequence (and/or an unlocking of the torque converter) to reduce engine compression braking.
But what happens if the driver suddenly decides that he/she wants to accelerate at just about the same time the transmission begins the upshift sequence?
The only "feedback" the transmission ECU has to "know" that the previously commanded gear shifting has completed (other than elapsed time)is via a comparison of the transmission input shaft rotational speed and the output shaft rotational speed.
Up until the 2004 model year these transmissions would react correctly to this sudden change of input, quick change from coastdown to acceleration, but by now Toyota had discovered an anomally in the design.
In some instances you couldn't just change the commanded gear selection right in the middle, or during, a previously commanded gear change without compromising the operation of the transmission. The transmission momentarily being in two gear ratios simultaneously, for instance.
So, the 2001 AWD RX300 required no transmission fluid replenishing or replacement for the life of the vehicle, according to the owners manual. But then a significant number of these transmissions began to fail prematurely. The dealers have now been told to advise owners of these vehicles that a 15,000 mile transmission flush and replenishment is recommended.
So, as of 2004 the firmware was rewritten and an e-throttle was added. With an e-throttle the engine can be prevented from developing torque until the transmission can complete the upshift it started at coastdown, and then be downshifted into the proper lower gear for acceleration once the e-throttle is given the GO signal.
A 1 to 2 second delay in acceleration wouldn't be all that unusual in this circumstance.
Get yourself a 2001 RX300 Lexus shop manual.
Or better yet an RX330 2004 or 5 shop manual and we can share resources.
Otherwise keep your ill-founded SECOND-GUESSING, SHARP-SHOOTING opinions to yourself!
you have to believe also that a 0.5 or 1.0 or 1.5 or 2.0 second hesitation would have been found to be completely unacceptable by Toyota's vehicle testers, and would have reported same to the developers *IF* the developers designed the system with that behavior. heck, the developers wouldn't want the tester's driving the car with that behavior, would they?
i'm (in the absence of objective quantitative information) giving Toyota engineers the benefit of the doubt. if your theory were correct, then one would expect the hesitation phenomenon to be much much much more widely reported; or you'd have to argue that Toyota / Lexus drivers aren't very discerning; and I doubt that to be the case.
i too am merely speculating that only a small number of owners experience the issue across a number of vehicles including the Sienna, Camry, Highlander, and I think the Solara or maybe it was the Avalon (?), and oh yes the Lexus.
and so, my theory is it may be a transducer / calibration / hardware issue of some form, which Toyota hopes to mitigate with more software.
I can see we're on different tracks here, so don't bother yourself any further about my questions.
Thanks for the feedback, even if it was a tad acrimonious.
I refuse to speculate on the number experiencing this problem, whether it is miniscule or widespread or somewhere in between. But, isn't it possible that everyone IS experiencing some degree of hesitation, but that it is slight enough in some vehicles or under some circumstances that it is not discernible? It is completely plausible even in wwest's scenario, that the hesitation would not be a uniform, say 2 seconds for the sake of an example, for everyone. Some may have just a fraction of a second delay while others have it noticeably (and dangerously, I might add) longer.
Or in this instance, ask someone who knows what they're talking about, like an experienced tranny service/repair technician.
I did just that this morning.
Had coffee with a good friend who owns and operates two independent tranny repair shops in SW Ontario.
We talked about this hesitation business.
Rather than stir up another hornet's nest, I won't bore anyone with facts, because I have the distinct impression that some might not want to hear them.
I would suggest anyone sincerely interested in getting to the core of the issue might consider doing the same. It was enlightening for me.
Quote: "Keep your ill-founded SECOND-GUESSING, SHARP-SHOOTING opinions to yourself!"
So I suggest you seek out your own counsel.
It worked well for me.
do you feel threatened or something?
I just don't care to light any more fuses.
Some of the things I learned will very likely do just that, because they contradict many assumptions and theories (perhaps hearsay too??)being discussed here.
By not stating the mechanics opinion (FACTS...) you seem to be agreeing that they are ill-founded. Is that the case?
This isn't the place for that kind of thing.
I'll post what I have to offer when things have calmed down.
In the meantime, why not let the dust settle and move on.
May I offer a few suggestions on how we might try to wrap some "standards" around some of these issues?
1. A theory isn't a bad thing. Gravity is a theory, but it's a pretty good one. So the word "theory" isn't by definition perjorative. All it means is "a systematic way of explaining an observed phenomenon".
Some theories are very spacey and anecdotal, others, like atomic theory, are ones that most of us believe in because of conspicuous explosions having occurred from time to time.
2. "Anecdotal" -- all this means is that it hasn't yet been subjected to rigorous scientific testing. It could be RIGHT, but it hasn't been tested. So telling someone his evidence is "anecdotal" isn't a slap in the puss, it's just saying, "so where's the data"?
Wanna know what I think? (please say "yes").
I think most conditions like "hesitation" require a combination of events to occur for the problem to occur, which makes it so elusive to pin down.
It's like the old "sludge" rpoblem that Toyota had. Many different things had to occur for the problem to show up apparently...some of which MIGHT have been related to a "design susceptibility" (my words).
Let's remember that we're here to enjoy ourselves and each other, okay?
thanks
Shifty the Host
Not as aggressive a driver as I thought I was....
And a more "educated" right foot then I thought.
Just drove the 2001 RX300 around a corner, TIGHT corner, with WOT.
Guess what?
It felt, about mid-turn, as if the engine had died on me.
Before I realized what I was doing I had lifted the gas pedal and reapplied it (old, OLD, habit from the days of accelerator pedal actuated fuel injector pumps??) and the engine roared back to life.
I have been puzzled by the fact that many of the posted complaints of hesitation had to do with turning while accelerating. So I went out and did my best to duplicate the exact parameters. Out of several tries the engine only "died" on me the one time.
The effect may have been the result of VSC activation but when I have experienced that in the past I always heard the brakes "rattling" and usually the aural indication. This time there was no indication of VSC activation.
Please keep us informed on how things work out for you!
If I go through with the arbitration (I have the paperwork sitting in front of me) will it forever stigmatize the car? In other words, will the arbitration process itself produce records that will be attached to the HL should I want to sell it or trade it in? I'm already regretting using my VIN on the NHTSA site since, for a few bucks anyone can gain access to that information.
Thanks.
p.s. wwest...sorry to hear that you've discovered that your vehicle has the hesitation. At least that's what it sounded like. I've driven several new HL's off the lot and can reproduce the hes at virtually anytime. Must be my driving style.
I recently bought a CarFax report prior to purchasing a used vehicle. I don't recall there being any category on it that would indicate whether the vehicle had been through arbitration. I will double check it, if I can still find it.
-------------
I am editing to add that I just checked the CarFax website and this is what they say is in the car record database:
"What is a Record?
A record is a significant event (in the vehicle's past) reported to CARFAX by one of our thousands of sources. CARFAX Reports contain important records that will answer crucial questions about the history of the used car you plan to buy, such as:
Was the car in a reported accident?
Does this car have open recalls?
Has the mileage been tampered with?
Was this car labeled a lemon?
How many owners drove this car?
...plus much more!"
A "lemon buy back" would be, though, or might be, depending on what records are produced.
They can however, be accessed by someone with a subscription to Law database(s)used for reference/precedent purposes on Court or Tribunal decisions.
Arbitrations are Administrative Tribunals. They are not bound by criminal standards of evidence, thus the rules of evidence are more relaxed. Plaintiff only needs to prove his/her contention through a standard of fairness and natural justice--ie, on balance of probabilities.
Onus of proof is on the plaintiff though, and you will need to do some rigorous homework in order to get the Arbitrator's attention. If you have documented evidence, make sure it's original or certified true copies. If you give verbal evidence, make sure it's corroborated by a witness or by documentation. You can call/question witnesses (ie a service rep for the company), but witnesses can be cross examined by your opponent and you can get clobbered if you're not careful.
Good luck.
Also, can you provide me with any further info on the arbitration cases you know of on the hesitation issue? Just a State or Local Jurusdiction is all I'm looking for.
I believe my only hope is that the climate within Toyota has started to change now that they recognize this as a problem. In fact my deciding factor to proceed with arbitration was when I herd more than one person representing Toyota use the word "problem" This was a significant shift from the total denial I was getting back in July and August. I'm still not very optimistic.
Did a comprehensive search for litigation of any type in all jurusdictions (Federal,State, Civil, Arbitration, Tribunal, etc.).
Tried using different keywords,ie, Transmission Hesitation,Engine Hesitation, Accelleration/Decelleration Hesitation,etc,for both Lexus and Toyota.
Nothing on record in any of the 50 States, 3 Territories, or DC.
Apparently there hasn't been any arbitration on the hesitation issue as yet DLA2, so you may be the first.
As I said earlier, best of luck. No harm in trying. Let us know how you made out.