Engine hesitation when accelarating quickly

<div class='quotetop'>QUOTE(priusenvy @ Aug 20 2006, 11:13 PM) [snapback]306587[/snapback]</div>

Isn't it doing that exactly? throttle-by-wire gives you as much power as it decides when it can give it to you (hence the hesitation when trying to pass), and then if the wheels slip it lets traction control back it off since it can't tell when you are going to loose traction until it happens. There's so much variability such as straight line, turning on a curve, etc.

It is agreed the traction control could be tuned a bit better, and maybe not give people the full electric torque if accelerating from stop. Then of course you would get sluggish acceleration. There was once a people-carrier that accelerated 0-60 in 28 seconds...

 

Re: Engine hesitation when accelerating quickly

Our Prius has around 13,500 miles on it. Yesterday as I was leaving a shopping center from a dead stop, I was accelerating when the the engine just died for about two seconds. I thought the car was going to die in the middle of the road. It was not a floor the gas pedal start, just a normal start. As I was slowing down the engine came back on and no more problems. The road was dry, no metal grates to cross, etc. I do not remember if the ICE was on when the problem occurred or not but it was on when I regained power. There was no reason for the VSC to have engaged to have caused this problem. This was the first time that this happened. I read thru various threads where other drivers had a similar problem but could not find an suitable answer. Anything new on hesitation?

 

Any traction control light on the dash? What you describe sounds like the traction control (TC) kicking, not VSC. I suspect something loose or slippery on the road surface.

Tom

 

I drive in Chicago so spend a lot of my time trying not to be crushed by trucks. I have noticed that, if I am trying to quickly accelerate to avoid becoming road pizza, the car seems to plateau at about 40-45 mph for a few seconds. This has happened several times on dry clean roadways so I doubt it is just TC. Never had (or expected) a car to let you down when you need acceleration the most.

 

I suppose not only in my country people have driven carburator cars in the past...

Some years ago it was a lot much usual to think not to floor quickly, because the carbs not always were well tuned.

To be used to inyection engines has done us a bit lazy about our feet.

 

It happened to my wife yesterday and she said that an icon came on the dash momentarily, we cheched the icon and sure enough it was the TC. She was starting out from a stop sign and crossing the wide white line opposite the stop sign when this occured. It is odd that it took one year for the first occurrence to happen, then twice in a week.

 

Coincidence; or, an additional year's worth of wear on the front tires (which wear faster than the rear).

 

I though I would link these two threads together:

http://priuschat.com/forums/care-ma...ing/43242-new-owner-brakes-locks-radio-2.html

After initial complaining/misunderstanding about more minor issues with the car (although brakes still scratch loud enough to scare people), there are more details on exactly what I noticed when the car seemed to decouple the revving engine from the turning wheels. At the time I had itchy for about six weeks and the tires probably had about 2-3K on them at the time.

I haven't contacted NTSB yet because I am hoping that there is a technical explaination about why this is happening and when it is likely to happen so I can avoid getting into this situation again.

 

Have you been able to determine exactly where the scratchy brake sound is coming from: front or rear, driver side or passenger side? Does the sound happen all the time? The sound is not normal and my guess is that you have a bit of road debris rubbing against moving brake parts.

Does this happen all the time, or intermittently?

I have a 2004 which doesn't "plateau", however when trying to quickly accelerate (for example, when entering the carpool lane on I-405 or I-5 in southern CA where traffic is flowing at 75 mph while adjacent lanes are moving at 45 mph) it helps to anticipate the need to accelerate, and press the accelerator pedal down about one second before I actually need the power. This issue was even more pronounced with my 2001 (which I recently sold.)

 

I have never seen this traction control light although traction control has engaged several times.
Could it be a Vehicle Stability Control light? My car hasn't got VSC.

 

vsc is vehicle stability control. it beeps when you lose control.

traction control is standard on every prius. it's there to make sure the electric motors don't burn themselves up... and you don't burn tires up.

the prius has 295ft-lbs of torque at 0rpm.. ive had times where i can spin a wheel and i don't even hear it.

 

It sounds like the scratching noise is coming from the back of the car. It happens the first 4-5x I brake after the car has sat for a little while (maybe an hour) each time getting a little quieter. The dealer said the mechanic would pull the tires and "inspect" the brakes, but, since he blew off my questions about the brakes, the mechanic really didn't know that I was having any problem with the car so may not have known to look closely. I should just take it back and ask to talk to the mechanic. With all of the pot holes around here IDOT has been dropping cold patch like crazy. Shoots up and showers the underside of the car because their mode of tamping it into the pot hole if for you to drive over it. Thanks - I will ask the mechanic to specifically look for it.

Once at that severity was enough. Other times the car is very sluggish when accelerating if it is already going 40-50 mph. I just don't trust it anymore. If Toyota knows that the car acts like this (the more standard hesitation at acceleration), it is their duty to point this out to the unenlightened instead of having us find out the hard way. My model for acceleration: I step on the gas, the car goes faster (doesn't red line and just sit there). I image that I am not alone in thinking this.

The loaner car the dealer gave me did have a slight hesitation before the ICE kicked in (turning left at a stop light) and the car surged forward. This was from a dead stop. The hesitation wasn't anything to get alarmed about because it lasted maybe a second or two. Itchy is not as responsive. I think the loaner also had better pickup while driving but I didn't floor it while in the 40-50 mph range. Does the car accelerate differently depending on the mph?

Thanks for the tip about anticipating the need to accelerate. I am going to find an open road to experiment with flooring it at different speeds so I get a feel for how the car is going to react. If I find that the problem is with me rather than the car, I am still going to be smoked that Toyota isn't doing a better job to pointing out the differences in accelerating a hybrid vs. a standard ICE. Before anyone asks - No - I haven't read the owners manual and didn't research the car first. But any salesperson who takes the time to point out every spot in the car I can put a cup into also has the time to tell me - "hey, this car has two engines and may not respond like a std ICE. Exp wth how acceleration feels because there may be hesitiation under heavy (or emergency) acceleration while the computer is coordinating the engine/motors efforts." And while they are at it "Keep steady pressure on the brakes when coming to a stop as the car may decelerate slower while switching between regen and friction brakes." (also something I had to find out after landing a car length into the intersection).

I am sure things will get better. Thanks to everyone for all of your help.

 

BMWs do that too. You floor the pedal. It starts to speed up then realizes you wanna go like a bat out of hell, changes down and then goes to warp. Also I think in the Prius the engine has to rev up first to apply more power to the generator to apply more juice to the motor to give you more torque to go go go.

 

Engine starts very early

Hi.

I am owner in Dominican Rep.

In these days, in the morning, the temperature is cool. I notice that the ICE (which has not melted yet here) is entering at once at 2 to 5 kms per hour. Is it normal? I thought that I could reach some 40 or 50 kms without getting the ICE to start even if the battery is in the green section. Gracias for the explanation.

Jean

 

It is time to all of us to think this over. We did not buy a race car when we bought our Prius cars, and we enjoy driving them but this hesitation (be it 1/2 or 1 second) can and maybe has already gotten someone either seriously injured or killed. We cannot predict how other people drive nor can we stop the ones that speed up because they see someone pulling on to the same road that they are driving on, and this does happen. maybe it is time for us to gather the statistics and have this looked in to by possibly a consumers group maybe? opinions are welcome.

 

Are you tripping or what?
The hesitation is so much less than a second and it was in the car you test drove. Once the Prius does go it leaps forward and makes up for the 3 nanosecond pause withiin the first second,

 

I can't think of anytime or place I've needed "emergency acceleration..." :faint:
I guess whoever drives like that just needs to learn how to drive more defensively...
Gunning for a gap in traffic is pretty bad driving... someone even mentioned turning right through a red light.

 

Right-On-Red is legal in most of the U.S. unless there's signage specifically prohibiting it (and some locales, like New York prohibit it).

But I agree that defensive driving helps. There are places that require either a very long wait, or gunning it for a gap though. I've had the traction control kick in on a few occasions in spots like that, but it's never caused a real problem, or even a close call. If the slipping continues for more than 1/2 second or so, I ease of the go-pedal and step on it again.

I don't know but it might be better just to leave your foot on the pedal. The alternative in a non-TC car would be to let your tires spin while you try to get traction. I don't think you accelerate any faster in that case!