Engine tries to stop, but won't, and cycles

<div class='quotetop'>QUOTE(swiftyprius @ Nov 13 2007, 08:57 PM) [snapback]539196[/snapback]</div>

Maybe the car was not warmed up yet? You could also use the recirculate option instead of cutting the fan off in order to block out the fumes from the car in front of you. Hope it's not a serious problem.....

 

The key here is going down the "pretty steep hill", which brought the SOC up to the top. As Evan points out, the Prius will spin its engine without gas when the SOC is too high, just to burn off some of the extra energy.

Tom

 

As for the stinky car, note that you can use a steering wheel button to manually set the A/C to recirculate and not suck in someone else's exhaust.

 

<div class='quotetop'>QUOTE(cheminee @ Nov 13 2007, 08:07 PM) [snapback]539201[/snapback]</div>

That's what I have found. If the coolant temp is not up to the optimal level, the ICE still wants to spin for a while no matter how much the battery is charged. The time it runs seems to correlate with how warm the coolant likely is. I don't have a scangauge or anything, but generally I've found two stages. It always runs about 10 seconds after startup for about 1-2 minutes no matter what. If I sit in Park and watch the energy monitor, it will charge the batteries for a while, then the tone of the ICE will change and will stop charging the batteries. If I put it in gear during this time, the ICE will shut down but start back up above 7-8 mph for another period of time no matter if I otherwise would be coasting or gliding.

Near our old place in Los Angeles, we would pull out of our garage and turn onto a four-lane street with a slight downhill grade, a 40 mph speed limit and no traffic light for about a mile. On days and times with little traffic (rare), I could pull onto that street, accelerate to 40, keep light pressure on the <strike>gas</strike> accelerator, and glide down to the light. But I found that, if it was the first trip of the day, the ICE would still be spinning as I slowed to approach that light, and I would not be at 99.9 as I slowed for the light. When the engine was warm, the ICE would not be spinning, and I would be at 99.9 mpg.

If it happens for more than a few minutes after it starts, I would worry. But it sounds like normal operation to me.

 

<div class='quotetop'>QUOTE(swiftyprius @ Nov 13 2007, 05:57 PM) [snapback]539196[/snapback]</div>

I have experienced the same "problem". My work is on a hill. Quite a few times when I left work and rolled down the hill, the battery was brought to green SOC, and at the stoplight at the bottom of the hill my ICE kicked in, cut out and then kicked back in, and kept cycling for about a minute. I did not have AC or even fan on. It is weird.

 

I don't believe it's a problem at all. Just let the HSD do its thing, in unusual situations it will sometimes act unusually. If it's normal when the situation is normal it's just character.

 

<div class='quotetop'>QUOTE(tank_3 @ Nov 28 2007, 02:14 AM) [snapback]545116[/snapback]</div>

It's not a problem. I explained it once in this thread, but here it goes again: When the SOC becomes too high, the Prius will spin the ICE without gas just to burn off the extra charge. You typically see this at the bottom of a long hill, when you come to a stop. The ICE will be off, then come on and race, then go off, then come on and race again. The cycle continues until the SOC is at an acceptable level. The engine is not really running, it's just being used as a load to waste energy.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 28 2007, 06:02 AM) [snapback]545162[/snapback]</div>

Thanks. It is good to be reassured.