Rough Idle

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:lolup: I am waiting for a situation like that with great anticipation...
[/b][/quote] Indeed, good one. I think I will phone my dealer on April 1 and ask to bring my car in because the engine keeps stalling...

 

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I've heard that the additives that they put into fuel in the winter effectively lowers the octane rating by a point or two. It might be worth it to try 89 octane and see if the knock persists.

 

I'm with the WAD crowd. When cold, the engine will idle a bit rough. Never nearly as bad as a car out of tune though. When it shuts down cold, you will notice. It DOES feel like a stall, sometimes rougher than others.

I can't always tell when it shuts off, even if I am trying to, when it is warmed up.

 

I just got my Prius one week ago, and it only has 450 miles on it. During the past couple of days, I have noticed the same thing. It happens regardless of whether the engine is cold. The idling is so rough that I feel the car shake every few seconds, almost as if a passenger has a restless foot. Oddly, when I shut off the heater, the vibrating went away. Perhaps the engine shut down when I shut off the heat, which would explain it.

-Doug in VA

 

Mine has never knocked, and it has very rarely given the stop-shudder (ICE always cold in cold temps when it shudders). If I drive in very cold weather (-30 C or colder BRRR) on the Trans Canada at 110 km/h, then do city driving, the ICE readily shuts down and NEVER shudders.

I always run the same gasoline from the same service station: Mohawk Ethanol Plus 90. I do this to avoid MMT anti-knock additives, which are common in regular unleaded non-blended Canadian gasolines.

A little manganese in your water table anybody??

Mohawk claims their AKI remains the same as they don't have to fool with "winter" blend as much.

 

The other thing I sometimes notice with a rough idle at a light is that the car feels like it's "surging" slightly as if it's still applying too much power to the wheels that I'm holding back with the brakes. I've felt this in park mode as well, so I don't think that's really the problem.

In any case, I've found that I can somewhat reduce the surging/rough idle feel by releasing the brakes a bit and allowing the car to move a few inches forward.

Odd...

Dave

 

Dave:

I've only noticed the "surge" a few times. It only happens first thing in the morning when I power up. It goes away after 5-10 secs.

 

I've only ever noticed it on the 2k4 not the 2k3 so don't know if it's MG related or what. On the 2k4 only under the first mile.

 

I've noticed the rough idle too, but the engine will shut off completely if I turn off or turn down the heat. I was assuming that the engine was just trying to warm up the coolant in the most fuel efficient means possible. I also assumed the this was being accomplished by either running a lean mixture, or shutting down some of the injectors.

 

Hmm, could be the octain, as Jayman uses 90. It's not enought for me to worry about though. Also note that the idle is higher than usual. It is not uncommon for a conventional car with high idle to diesel a bit.

 

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Just found this forum. Thank God that others are having the same problem. I only have about 500 miles on my Prius - but started experienceing the rough idle problem at about 100mi.

The rough engine shut off/on happens to me in cold and warm weather - and the engine seems to come on when in reverse no matter what. The dealer mechanic tells me that all 04/05 prius models have this issue (that the 03's did not), but I find this hard to believe. Does anyone have a solution for this problem?

I have been using reg. unleaded on my first fillup and there is no difference in performance. Also - anyone having mpg readings of 3-10 mpg when the engine first turns on and/or accelerating? Thanks...

 

if you read thru this entire post you'll notice that most of the problems are 2k4-5 related. After the first 4-5 thousand mile it tends to diminish unless the BSOC is low then it seems that MG1 is causing some roughness or surging when the car is stopped and the generator is trying to put some charge into the battery. If all the parameters are right for a shut down it seems that the load on the ICE from MG1 causes a slight shudder as the ICE stops. I noticed some slight roughness at idle in my 2k3 but it hasn't done it since about 3-4000KM. The wifes 2k4 still does it when it's cold and the battery is low.

 

as to the car starting in reverse that is a function of the CVT. The ICE doesn't drive the car directly like a conventional car. The MG2 (main drive motor) does all the work in reverse so the only contribution that the ICE can provide is to run MG1 to provide power for MG2 and to charge the battery. You mentioned that your new to PC so have a look at this URL and you will get an understanding of the function of the CVT http://homepage.mac.com/inachan/prius/planet_e.html

 

I'm not sure if this is a similar issue, but I've noticed recently that when I am stopped at a light, my 2005 Prius will occasionally spaz out with turning the ICE on and off every second. One second on. One second off. One second on. One second off. The weather is somewhat cold out (36 F), but this behavior seems odd. When this happened today, I noticed that my battery strength was very good, and I had everything off except the CD player. Anyone seen this before?

 

Happened to me also same battery state same outside temp the ICE kept going on off on off every sec until I shut it down. Took It to Toyota Could not find a problem no codes.

 

try putting it into "B" for a few seconds and then shift it back to "D" that'll probably stop it cycling. It's been reported before early last year and if memory serves me about the same temps as your reporting.