ICE runs rough as is shuts down

Hmm, not sure if it's rough. When you're paying attention to it, it is noticable, but the people I had in my car to show what it feels like to sit in a Hybrid never noticed anything.

 

My prii do as well but no dealer has no crue

 

I've noticed it from time to time as well - it certainly doesn't happen all the time - usually the transition is very gentle, but occasionally the engine sputters a bit as it shuts down.

I suspect it's due to the gas engine firing the plugs after the fuel has been cut-off to ensure the complete combustion of any vapor remaining in the cylinders. The car needs to do this type of thing to make sure that it's not just venting unburned or partially burned fuel.

May have something to do with the quality of gas the tank was filled with?

Dave.

 

It happens to me every morning at the same light. At first it bothered me a bit, now I just accept it as normal.

 

Sometimes it does, sometimes it doesn't.

As pointed out above, apparently the Prius is very meticulous about cleaning up after iteslf.

It will make sure that it burns off any fuel in the cylinders even if it makes a 'thump' as the last one fires. Better than dumping raw gas out the exhaust for sure.

 

I agree Evan. After 14k miles, either I don't notice it or it's happening less here too.

-m.

 

Every morning I stop at a light about 45 seconds from my house. Although I am fully stopped, and the diagrams indicate that the engine is not delivering power anywhere, I can feel the engine running. Unless I move forward in a few seconds, the ICE turns off with a shudder. I believe that this shudder effect usually happens during the initial warm-up cycle.

 

I also notice it during the initial warm-up period. After that it's much smoother. Occasionally there's a rougher-than-normal shut-off when it's warm, but generally it's when it's cold. BTW, the ICE is much more reluctant to shut off during the warm-up period. Sometimes it will wait a full slow count to ten.

This may be just my imagination, but I believe it's much more reluctant to shut off when it's in S3 than in S2. (S4 is full hybrid operation.)

 

I've noticed this too, and not just during warm up or when it is cold. My other car has a manual transmission and whenever I come to a top in the Prius and the ICE is still running, it has me reaching for the clutch because the shutdown is so rough. I've got about 8000 miles on the car, and when I asked the dealer about it when I brought it in for service, he just said, "Yeah, a lot of people complain about that". Nothing about if it was a problem or if they could fix it.

 

ya i noticed the shudder too, but as others have said, it seems to only be noticable when the vehicle is cold.

after the warmup, i frequently have difficulty telling if the motor is on... (although i can feel it when it kicks off) so i guess i would have to say that it runs much smoother.

i chalk it up to being an ICE. every car i have ever had, just idled much higher to compensate for the rough idling when cold.

i guess if it bothers you, you might try putting it in neutral and holding your foot on the gas...

jk

 

I've noticed it on both mine and the wifes. I think it has to do with the ICE coolant getting up to 70C which it does very quickly but the engine oil is still probably quite cool and as such doesn't release the VVT mechanism fast so the cam has to be rotating for a few seconds to get the cam timing retarded to have the compression down to the 9 to one range so it will start easier. 1000RPM and it starts to roughen and 996 get's the shakes 958 drops to 0 RPM

 

OK Daniel be gentle but how does one tell (in a 04) when one is in S1, S2, S3 & S4. I understand the concept but not the application. Enlighten me a bit. Remember use words of on syllable or less I can be incredibly dense.

 

You can't really tell. I want an indicator. As I understand it (and I'm not entirely sure here) in S1 the engine will not shut off unless you stop the car. At a certain temperature it goes into S2, and at full operating temp it goes into S3. When, and under what conditions, it will shut down are slightly different in S2 and S3, but contrary to what I would expect, it seems more reluctant to shut off in S3 than in S2.

It will not run in electric mode alone in S1, S2, or S3, except that in S3 it will, if you exceed a certain speed (around 35 mph, I think, not sure) but after a brief stop it won't again.

To get into S4 you have to stop for either 5 or 10 seconds, depending on I don't know what.

You can engage EV mode from S3 (and maybe S2 ???) if you have the switch, but after disengaging it you still won't be in S4.

It's very frustrating because if you never go over about 35 and never come to a long stop, you'll never get into full hybrid operation. My commute takes me way beyond full warm-up without ever going fast, and the stop signs are just brief stops unless nobody is behind me and I wait; and depending on the lights I can sometimes get all the way downtown without ever having a long stop, so the car never goes into S4.

At least if there was an indicator I'd know when to pull over to the curb to stop for 10 seconds. But why in the world can't they just make it go into S4 as soon as it's warm enough??? that's the thing that most baffles and annoys me!

You can tell when you are in S4 operation because if you feather the pedal you can get it to go into electric mode. Except that if you have gone over about 35 mph it can operate full-hybrid without actually being in S4.

 

Thanks. I would say that we need that monitor thingie that people are working on. I love this technology but I want to understand it. Of course I want to understand everything. So much to know so little time. Have you notices that at speed if you go from coasting with recharge to gliding that you can kick it into electric mode with very very gentle pressure on the accelerator. It seems easier to do if you go through the no power transfer glide mode first. On my commute I have a very short 25 mph section, followed by a 40 mph section (about 1-2 miles), then a longish 50 mph country road. If I am very carful I can get it into electric after a very minor down hill area at 50 and keep it there for 3-4 miles before a small rise and I have to engage the ICE to maintain speed usual 48 or 49.
I really get a kick out of this car.

 

See previous topic linked below for further info regarding the 4 different stages:

http://priuschat.com/forums/viewtopic.php?t=3307

 

Some folks refer to this as "feathering" the pedal. At one point I got tired of doing this, and went to "just drive it," and I found that it still went into electric mode all by itself. Feathering the pedal only seems to make it happen a very short time sooner.

I had not noticed this.

 

I dont think EV mode is the most efficient way of moving except at very low speeds.

you will get much better mileage with the ICE when it doesnt have to charge the battery.

in fact you may notice your best gas mileage will happen at 35-50 mph if at a constant speed after the ICE is warmed up.

the best way to moderate this is use the cruise control as much as possible. after i went to maximum use of cruise control, my mileage immediately increased 2-3 mpg.

yes it takes diligence to use cruise control on surface streets in traffic. but what it also does is forces you to pay attention to traffic flow and anticipate stops more.

try commuting home using the criuse control as soon as you hit 35 mph and see how long you can remain in cruise control. you can vary your speed in 1 mph increments. you can also hold the control up or down and increase or decrease speed very slowly (i would guess it changes about 1mph/sec.

keep in mind that touching the brakes will kick you out. but i think you will find your mileage will increase more using this method than any kind of "stealth" driving. in reality, it is stealth driving except you have the car's computer (and cruise control) helping you out.

 

Maybe S3/S4 mode things is designed to boost EPA consumption test ratings?