My New 08 Prius shakes at a stop

Hi dongwoo. Welcome.

That shaking you described has never happened to me. I don't think it's normal. I would take it back to the dealer.

 

I have mine about 2 months so far. You will feel a slight shudder as the gas engine shuts down at lights and the like. Sometimes it's more noticeable than others but as a general rule, it's most noticeable in the first 10 minutes or so of driving. You should have felt it on a test drive. It's really the primary difference as I see from driving a regular gas powered car and a Prius. It's still a bit disconcerting at times because you're mentally conditioned to think the car has conked out but then you press the pedal and it moves and all is right with the world as you get your 50mpg. Temperature also impacts the severity of the shudder and how many minutes it takes to warm up and as a general rule mileage does drop a bit as the temperature drops. On my typical commute in Sept and first half of October I was averaging about 52mpg and that same commute the last two weeks with colder mornings is around 49-50mpg.

 

Yep, normal. The petrol engine doesn't always shut down as soon as you lift your foot, sometimes it will run until you stop then it shuts down.

I believe I read a post from an owner who has a scan gauge and he said it happens in the transition from S3 to S4 which is the stage where electric operation becomes easier to achieve so it's a good thing.
I could have that wrong and I'm sure someone will come put me right if I am but if that's the only symptom don't worry about it, it's fine.

 

<div class='quotetop'>QUOTE(Paul R @ Nov 3 2007, 12:09 PM) [snapback]534310[/snapback]</div>

Yes, that's a good description -- "slight shudder". That's normal. But "shaking" may not be.

 

I've noticed that the most noticeable engine shut-offs are when the engine has just warmed up enough to shut off at a light. I've also noticed that this seems to be more pronounced in the afternoon, when the car has been parked at work.

I can't really explain it, but it seems "they all do that." Things get smoother after that first dramatic shut-off.

Harry

 

Yes, it's normal for the Prius to shudder when the engine shuts off at a stop. Most drivers find it more pronounced when the engine is new and in colder weather. When the Prius shuts down the engine, it always spins it around to the same stopping place. If it misses on the first try, it will spin it around again. This is one of its many tricks to reduce starting emissions.

Tom

 

When my 04 was new and run cold, the first shutdown would really shake the car. With a few miles behind it, and the use of a winter front in cold temps, it hardly shudders at all.

 

I notice the same thing on my 05 when the outside air is running below 45f. Jayman has it right, if you can block the cold air coming in through the front intakes you will notice a difference in the 'shut down' shake that every Prius has as the gas engine shuts off.

A simple way to check is to flip to the view on your console that shows when the ICE (Infernal Combustion Engine) is on or off. The shake likely coincides with your engine shutting off. If it does not happen when the engine is shutting off I would get it to a reputable dealer to check out.

 

<div class='quotetop'>QUOTE(Boo @ Nov 3 2007, 11:21 AM) [snapback]534314[/snapback]</div>

It sounds like one new owner's shake is another new owner's shudder.

 

<div class='quotetop'>QUOTE(dongwoo @ Nov 3 2007, 03:31 PM) [snapback]534375[/snapback]</div>

First post here.

I'm having exactly the same "problem" with my '07 Touring (2 months new with 2,000 miles on it). The shudder is VERY pronounced at the first stop and it makes quite a racket. In fact, the car even lunges forward a bit at the stop when the engine is cold... with the brake applied. It started doing this within the last 700 miles or so. It's disappointing to me that this would be considered "normal" operation. It shuts down quite smoothly when the engine is warm, though.

I'll probably be taking mine to the dealer to check out.

TS
California

 

<div class='quotetop'>QUOTE(TSFlyer @ Nov 7 2007, 11:34 PM) [snapback]536529[/snapback]</div>

Lunging forward at shut down is not normal. The normal shake is just a little shudder as the engine rotates around to the standard stopping position. It sounds like you need a visit to the dealer.

Tom

 

<div class='quotetop'>QUOTE(dongwoo @ Nov 3 2007, 12:31 PM) [snapback]534375[/snapback]</div>

My '07 does this too, more noticeable some times than others, I've gotten used to it and I average 50mpg, so I have no complaints.

 

<div class='quotetop'>QUOTE(TSFlyer @ Nov 7 2007, 10:34 PM) [snapback]536529[/snapback]</div>

Is the lunging while stopping? Does it start "lunging" right as you hit 7mph or below? If so, then that is "normal"... assuming of course your describing the transition from regen to friction brakes.

 

Thanks for the replies Tom and Bob64.

Yes, the car is literally stopped, 0 mph, when it lunges as the engine shuts down.

Here's the typical scenario:
- Back out of my garage/driveway - halfway out the engine turns on. Cold engine has higher RPM. So far so good.
- Drive to the first major intersection a few hundred feet away where I always have to stop for traffic, still high RPM - the engine turns off with major fanfare/racket after I've been stopped for about 30 seconds. At the same time the car actually lunges forward a bit as the engine shuts down, since it seems that the engine shut down is quite rough. It literally sounds like a major mechanical failure each time the engine shuts down for the first time when cold.

Anyway, I'm definitely taking it to the dealer to check out.

Thanks again.

TS

 

This post that Hobbit wrote back in June explained to me what's going on better than any others I have read. I really thought something was wrong with my car when I first got it last winter until I began to understand how unique this car really is:

http://priuschat.com/index.php?act=ST&...st&p=463825

 

One thing that old post also didn't point out is the inertia of MG1.
Since all the drivetrain components are always linked together, any
slight change in engine speed implies a roughly 3x commeasurate
change in MG1's speed -- which is a fairly small rotor but certainly
not zero mass, so that little bit of torque backlash also has a
component that goes out through the final drive and pushes on the
wheels a little bit. That's also why the car tends to shake a bit
more than others when it's idling in Neutral [no MG control, entirely
subject to passive rotor inertia].
.
_H*