High speed pulsing/surging/dragging...anyone else feel it?

upland_bill · 05-03-2006, 09:10 AM

I recently purchased a loaded 2005 Prius with 15,000 miles, and am loving it. I went from a BMW M5 to a Prius, which is remarkable in itself. I am amazed at myself at how my horsepower desire was so easily replaced with my effeciency goals, which in turn completely changed my way of driving.

However, that is not the purpose of this post. The car has been great and I have adjusted to the various clunks and grinds of the engagement of motors adn the CVT at 'around town' speeds. However, I have noticed a sensation at high speed (around 60) that concerns me. What it really feels like is a brake dragging. However, that is a sensation you would expect to feel at a slower speed. The other way to describe it is as a pulsing or a gentle surge. The frequency is high, several seconds. Is it just me? Most of my driving is NOT on the highway, so I don't get the chance to observe it, but I am getting concerned. This would be when the gas and electic are both engaged and the car is under a low to moderate load to maintain speed. So, if no one else experiences this sensation, then I will pursue other possibilities with the Dealer.

Thanks!

john1701a · 05-03-2006, 09:25 AM

That sure sounds like a wheel issue to me. If you speed up a little bit and it goes away, I'd definitely have the balance and/or alignment checked. Of course, the tires themselves may reveal the problem if there is enough wear no to indicate an uneven amount of tread.

McShemp · 05-03-2006, 09:36 AM

You mention this is when the ICE and electric motors are both engaged. Could be your speed and the car's control strategy are in just the right (or wrong) place to have you switching modes between motor assist being on and off. Thus, the electric motor kicks in for a few seconds, you speed up without changing the pedal command, and the electric motor stops again. You slow down and the motor kicks in again.

Is your issue repeatable at a range of speeds? (say +/- 5 mph) Try getting on a stretch of level road and getting up to the speed where this happens. Set the CC and watch the MFD (energy screen) to see what's happening (remember, there's a slight delay). Then use the CC to increase and decrease you cruising speed while observing the MFD.

keydiver · 05-03-2006, 12:40 PM

That "surging" is really the only thing that bugs my wife when she drives it. I *think* it only seems to happen once the car is done recharging the battery, and then is trying to assist you to maintain speed by mixing in little "spurts" of electric power. Thats my theory.

Bill Lumbergh · 05-03-2006, 12:48 PM

Is the A/C on? If so, it can manifest itself as a slight surging as the compressor cycles on and off. Does it occur with the cruise control on?

jbarnhart · 05-03-2006, 01:18 PM

I feel the surging in my 2006. It's the only odd characteristic about driving my Prius. As you say, it isn't noticable at low speeds, but only when highway driving without using the CC. It feels like you can't get the car to drive at a consistent speed without modulating the pedal. Oddly enough, I think my Prius gets better milage when I drive it without the CC and let it surge a little.

Prizzle · 05-03-2006, 01:46 PM

<div class='quotetop'>QUOTE(upland_bill @ May 3 2006, 09:10 AM) [snapback]249026[/snapback]</div>

Quote:

I recently purchased a loaded 2005 Prius with 15,000 miles, and am loving it. I went from a BMW M5 to a Prius, which is remarkable in itself. I am amazed at myself at how my horsepower desire was so easily replaced with my effeciency goals, which in turn completely changed my way of driving.

However, that is not the purpose of this post. The car has been great and I have adjusted to the various clunks and grinds of the engagement of motors adn the CVT at 'around town' speeds. However, I have noticed a sensation at high speed (around 60) that concerns me. What it really feels like is a brake dragging. However, that is a sensation you would expect to feel at a slower speed. The other way to describe it is as a pulsing or a gentle surge. The frequency is high, several seconds. Is it just me? Most of my driving is NOT on the highway, so I don't get the chance to observe it, but I am getting concerned. This would be when the gas and electic are both engaged and the car is under a low to moderate load to maintain speed. So, if no one else experiences this sensation, then I will pursue other possibilities with the Dealer.

Thanks!
[/b]

We've had ours a week and noticed exactly the same thing at 60 mph+. Like there is something pulling at the car or like being buffeted around behind an 18 wheeler. Seeing this regularly discussed on Priuschat, I am writing this off to one of the quirks of the car, not a defect in mine. I get the sense it may relate to the aerodynamics of the car as well as perhaps to the relationship between the long wheelbase and the narrow tracking width. I have already ordered the stiffening brace in the hopes it will contribute to some improvement.

mmmdowning · 05-03-2006, 03:03 PM

I think McShemp is on the money. Your at the center of going gas and electric. I get it on my 2006. I drive about 114 miles a day 90% hwy. I do a lot of lifting off the gas and applying the gas pedal.

upland_bill · 05-04-2006, 08:54 AM

Thanks for all the responses.

For the person that mentioned this had been discussed previously, I will search again to find it, or those, and see what transpired.
I had also thought it might a wheel issue, especially since the car is 1 year old with the original tires (I never did ask how the fellow did so many miles in 1 year ... oops).
For those that feel they have felt the same sensation ... I now feel at ease. I will of course continue to monitor and obsess, but not worry.

Thanks Again.

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05-03-2006, 09:10 AM	#1
upland_bill Join Date: Apr 2006 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I recently purchased a loaded 2005 Prius with 15,000 miles, and am loving it. I went from a BMW M5 to a Prius, which is remarkable in itself. I am amazed at myself at how my horsepower desire was so easily replaced with my effeciency goals, which in turn completely changed my way of driving. However, that is not the purpose of this post. The car has been great and I have adjusted to the various clunks and grinds of the engagement of motors adn the CVT at 'around town' speeds. However, I have noticed a sensation at high speed (around 60) that concerns me. What it really feels like is a brake dragging. However, that is a sensation you would expect to feel at a slower speed. The other way to describe it is as a pulsing or a gentle surge. The frequency is high, several seconds. Is it just me? Most of my driving is NOT on the highway, so I don't get the chance to observe it, but I am getting concerned. This would be when the gas and electic are both engaged and the car is under a low to moderate load to maintain speed. So, if no one else experiences this sensation, then I will pursue other possibilities with the Dealer. Thanks!

05-03-2006, 09:25 AM	#2
john1701a Senior Member Join Date: Jan 2004 Location: Minnesota Posts: 2,721 My Car: 2004 Prius Package: Pioneer #3 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 3	That sure sounds like a wheel issue to me. If you speed up a little bit and it goes away, I'd definitely have the balance and/or alignment checked. Of course, the tires themselves may reveal the problem if there is enough wear no to indicate an uneven amount of tread.

05-03-2006, 09:36 AM	#3
McShemp Senior Member Join Date: Sep 2005 Location: SA, TX Posts: 344 My Car: 2006 Prius Package: #5 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	You mention this is when the ICE and electric motors are both engaged. Could be your speed and the car's control strategy are in just the right (or wrong) place to have you switching modes between motor assist being on and off. Thus, the electric motor kicks in for a few seconds, you speed up without changing the pedal command, and the electric motor stops again. You slow down and the motor kicks in again. Is your issue repeatable at a range of speeds? (say +/- 5 mph) Try getting on a stretch of level road and getting up to the speed where this happens. Set the CC and watch the MFD (energy screen) to see what's happening (remember, there's a slight delay). Then use the CC to increase and decrease you cruising speed while observing the MFD.

05-03-2006, 12:40 PM	#4
keydiver Senior Member Join Date: Sep 2005 Location: Hobe Sound, Florida Posts: 508 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	That "surging" is really the only thing that bugs my wife when she drives it. I think it only seems to happen once the car is done recharging the battery, and then is trying to assist you to maintain speed by mixing in little "spurts" of electric power. Thats my theory.

05-03-2006, 12:48 PM	#5
Bill Lumbergh USAF Aircraft Maintainer Join Date: Jul 2005 Location: Marysville, CA Posts: 516 My Car: 2005 Prius Package: #1 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 1	Is the A/C on? If so, it can manifest itself as a slight surging as the compressor cycles on and off. Does it occur with the cruise control on?

05-03-2006, 01:18 PM	#6
jbarnhart Join Date: Jan 2004 Location: Santa Clara, CA Posts: 628 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 1	I feel the surging in my 2006. It's the only odd characteristic about driving my Prius. As you say, it isn't noticable at low speeds, but only when highway driving without using the CC. It feels like you can't get the car to drive at a consistent speed without modulating the pedal. Oddly enough, I think my Prius gets better milage when I drive it without the CC and let it surge a little.

05-03-2006, 03:03 PM	#8
mmmdowning Junior Member Join Date: Apr 2006 Location: Spotsylvania, VA Posts: 22 My Car: 2006 Prius Package: #6 Touring Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I think McShemp is on the money. Your at the center of going gas and electric. I get it on my 2006. I drive about 114 miles a day 90% hwy. I do a lot of lifting off the gas and applying the gas pedal.

05-04-2006, 08:54 AM	#9
upland_bill Join Date: Apr 2006 Posts: 10 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Thanks for all the responses. For the person that mentioned this had been discussed previously, I will search again to find it, or those, and see what transpired. I had also thought it might a wheel issue, especially since the car is 1 year old with the original tires (I never did ask how the fellow did so many miles in 1 year ... oops). For those that feel they have felt the same sensation ... I now feel at ease. I will of course continue to monitor and obsess, but not worry. Thanks Again.