Rough idle plus 'lumpy' start stop?

abtim · 10-19-2007, 04:17 PM

I have a 06 Prius which the idle seems quite rough and lumpy. The main time I notice it is when the petrol engine comes in and out as the car shakes a little as if the engine doesn't quite turn off properly. When it comes on it then thumps in. The dealer says it is within limits blah blah.... but it just doesn't feel right.

Anyone else have this problem or at least; what is normal?

Cheers

Devil's Advocate · 10-19-2007, 04:55 PM

The automatic on/off differs depending on conditions. Some days you don't even notice and some days you're like the whole thing is shaking. Pretty normal. Cold usually causes rougher starts and stops.

qbee42 · 10-19-2007, 04:55 PM

This is normal. The ICE only stops in one position, and if it misses, MG1 will spin it around and try again. Most people notice these rough shut-downs when the engine is new, cold, or both. It's just part of the low emissions of the Prius.

Tom

abtim · 10-20-2007, 09:15 AM

Thanks for that. It was less of the lumpy start stop which I do understand is to do with the engine clearing the fuel. The bit that I am not so happy about is that when the engine does idle iw it is charging the main battery or you have aircon on - the whole car shakes. I would have thought that a car of this expense would have a really smooth idle. My Saab of 200000 miles has a far smoother idle.

Any thoughts?

donee · 10-20-2007, 09:48 AM

Hi PriusBrit,

Water in the gas is my guess, if its allot different than previously. I had something similar happend, but it was 5 degree F for the high temp that week. Bought gas from a station I usually don't, as it was the only one with an open pump. Next tank, no problems, even at similar temps.

hobbit · 10-20-2007, 12:35 PM

Ooh, that was the theory we came up with a couple of nights ago after
I tanked up, drove about half a mile and then let the car sit for a
day and a half. In the meantime someone who didn't quite understand
the user interface powered up to READY to get the windows open, and
powered off just after the engine lit for its warmup cycle. Next
time I went to start, the ICE felt like it was on about a cylinder
and a half for a little while, and then finally leveled out. It
was very humid that night and someone suggested "spark plug wires?"
until I pointed out that there aren't any in this car and the
ignitors are pretty well protected down in their little wells.
But a little water in the gas, that then had plenty of time to
settle down around the tank pickup, sounded plausible. The MPG was
also absolute crap for the first third or so of our return trip
home, and began to pick up a little later.
.
Keep in mind that we're getting into colder weather, and this tends
to make Priuses whose throttle bodies haven't been maintained and
cleaned well start droppin' like flies with no-starts. Happened
last year, too. Suggest you get out there and clean those suckers
up [don't spray, just wipe] while there's still some warm weather.
.
_H*

hyo silver · 10-20-2007, 12:41 PM

Sounds to me like it could be electrical. I had a similar, though more severe problem that turned out to be $500 worth of towing, plugs, and coils caused by water getting in. The Prius is not waterproof.

richard schumacher · 10-20-2007, 02:02 PM

<div class='quotetop'>QUOTE(hyo silver @ Oct 20 2007, 11:41 AM) [snapback]528178[/snapback]</div>

Quote:

Sounds to me like it could be electrical. I had a similar, though more severe problem that turned out to be $500 worth of towing, plugs, and coils caused by water getting in. The Prius is not waterproof.
[/b]

Did you ever wash or hose down the engine?

hyo silver · 10-20-2007, 02:13 PM

<div class='quotetop'>QUOTE(richard schumacher @ 2007 10 20 11:02) [snapback]528209[/snapback]</div>

Quote:

Did you ever wash or hose down the engine?
[/b]

No. Driving in the rain is apparently sufficient.

abtim · 10-20-2007, 02:20 PM

Hi Hobbit

Is there a technical term for throttle body? Thought I could try that on the dealers

Thanks!

PS My MPG seems to have also dropped from 55 to 33. Bizarre.

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10-19-2007, 04:17 PM	#1
abtim Join Date: Oct 2007 Posts: 3 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I have a 06 Prius which the idle seems quite rough and lumpy. The main time I notice it is when the petrol engine comes in and out as the car shakes a little as if the engine doesn't quite turn off properly. When it comes on it then thumps in. The dealer says it is within limits blah blah.... but it just doesn't feel right. Anyone else have this problem or at least; what is normal? Cheers

10-19-2007, 04:55 PM	#2
Devil's Advocate Senior Member Join Date: Mar 2005 Location: Las Vegas, Nevada Posts: 917 My Car: 2005 Prius Model: Package: #9 Thanks: 0 Thanked 1 Time in 1 Post Friends: 0	The automatic on/off differs depending on conditions. Some days you don't even notice and some days you're like the whole thing is shaking. Pretty normal. Cold usually causes rougher starts and stops.

10-19-2007, 04:55 PM	#3
qbee42 Senior Member Join Date: Mar 2006 Location: Northern Michigan Posts: 12,260 My Car: 2006 Prius Model: Package: #7 Thanks: 356 Thanked 828 Times in 604 Posts Friends: 14	This is normal. The ICE only stops in one position, and if it misses, MG1 will spin it around and try again. Most people notice these rough shut-downs when the engine is new, cold, or both. It's just part of the low emissions of the Prius. Tom

10-20-2007, 09:15 AM	#4
abtim Join Date: Oct 2007 Posts: 3 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Thanks for that. It was less of the lumpy start stop which I do understand is to do with the engine clearing the fuel. The bit that I am not so happy about is that when the engine does idle iw it is charging the main battery or you have aircon on - the whole car shakes. I would have thought that a car of this expense would have a really smooth idle. My Saab of 200000 miles has a far smoother idle. Any thoughts?

10-20-2007, 09:48 AM	#5
donee Senior Member Join Date: Aug 2005 Location: Chicagoland Posts: 2,323 My Car: 2006 Prius Model: Package: #2 Thanks: 2 Thanked 73 Times in 64 Posts Friends: 0	Hi PriusBrit, Water in the gas is my guess, if its allot different than previously. I had something similar happend, but it was 5 degree F for the high temp that week. Bought gas from a station I usually don't, as it was the only one with an open pump. Next tank, no problems, even at similar temps.

10-20-2007, 12:35 PM	#6
hobbit Senior Member Join Date: Mar 2005 Location: Bahstahn Posts: 3,830 My Car: 2004 Prius Model: N/A Package: Base Thanks: 0 Thanked 332 Times in 165 Posts Friends: 0	Ooh, that was the theory we came up with a couple of nights ago after I tanked up, drove about half a mile and then let the car sit for a day and a half. In the meantime someone who didn't quite understand the user interface powered up to READY to get the windows open, and powered off just after the engine lit for its warmup cycle. Next time I went to start, the ICE felt like it was on about a cylinder and a half for a little while, and then finally leveled out. It was very humid that night and someone suggested "spark plug wires?" until I pointed out that there aren't any in this car and the ignitors are pretty well protected down in their little wells. But a little water in the gas, that then had plenty of time to settle down around the tank pickup, sounded plausible. The MPG was also absolute crap for the first third or so of our return trip home, and began to pick up a little later. . Keep in mind that we're getting into colder weather, and this tends to make Priuses whose throttle bodies haven't been maintained and cleaned well start droppin' like flies with no-starts. Happened last year, too. Suggest you get out there and clean those suckers up [don't spray, just wipe] while there's still some warm weather. . _H*

10-20-2007, 12:41 PM	#7
hyo silver awaaay Join Date: Mar 2005 Location: Vancouver, BC Posts: 11,551 My Car: 2004 Prius Model: Package: Base Thanks: 83 Thanked 228 Times in 167 Posts Friends: 64	Sounds to me like it could be electrical. I had a similar, though more severe problem that turned out to be $500 worth of towing, plugs, and coils caused by water getting in. The Prius is not waterproof.

10-20-2007, 02:20 PM	#10
abtim Join Date: Oct 2007 Posts: 3 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Hi Hobbit Is there a technical term for throttle body? Thought I could try that on the dealers Thanks! PS My MPG seems to have also dropped from 55 to 33. Bizarre.