Gas engine turning on & off rapidly in rush hour traffic with hot weather and AC running

You should try it with the defroster setting, like windshield defroster only. That thing always makes my car run, even when the battery is fully charged. I do have a 2002 model though, so it could be different for you.

BTW, I'm from Texas and know what you are talking about. Been during the summer and winter months. Summer isn't even that bad. I don't believe I've been there in 100+ degree weather though, as I haven't been during the summer in many years. I do however live in Georgia now, and the summer here is just as long. Started in early March this year and except for like 1 week where it went back to winter it's been over 70 degrees everyday so far. I've already seen 90+ according to my Prius, but it was probably closer to 85 and it's not even the peak season yet.

I just roll two windows down about an inch or two and I'm usually just fine, even when I'm stopped at a light. I've noticed how having two windows open gives you more of a draft, presumably because the air flows between them.

My $.02.

 

I think someone mentioned in another thread about how to charge the battery. As far as I remember, you press the brake, then press the gas pedal to the half way point. That should turn on the engine and charge the battery.

 

Hi local host...

I'm not sure WHERE in Texas you live (sounds a lot like Houston), but in the Dallas Summer (frequently, we have up to 25 or more days over 100º in the Summer), I have found my Prius, both the 2004 traded for my current 2007, to NOT cycle the ICE excessively. I normally set the A/C to "Automatic" and in the hottest days at about 74º to 76º. About the only other city in Texas with consistently higher temperatures is Wichita Falls. I have never felt the need to lower the windows for ventilation. As for a "reasonable" temperature, when it's 105º outside, 76º or 78º seems reasonable to me.

Evan has offered good information and advice. From what I've read, your Prius is functioning as designed. Maybe you are hypersensitive to heat, some folks are. Ultimately, YOU are the only judge regarding what is comfortable for you. Don't be concerned about being "down to one bar," the MFD display only shows the SOC of your main battery between 40% and 80% - your Prius computers will maintain that range of charge automatically.

 

<div class='quotetop'>QUOTE(local_host @ Apr 28 2007, 04:17 PM) [snapback]431797[/snapback]</div>

Ever try it in a car with a stick shift? THAT is the pits in 5-10mph stop & go traffic. 45 minutes of that and you may as well have walked home, particularly if it's an older car with a stiffer clutch pedal. Been there, done that, in 95F+ temps and high humidity in a car with black leather seats and an aging A/C system.

I guess I don't see what the big deal is. The gas engine turns on, the gas engine turns off...that's what a Prius does. It's just trying to save you some gas, which is what Toyota designed it to do. At least YOU don't have to do anything but step on the accelerator when you want to go and step on the brake when you want to stop. Am I missing something here? Like Charles said, the car takes care of its own health so you don't need to worry about anything bad happening while this is going on.

 

<div class='quotetop'>QUOTE(local_host @ Apr 28 2007, 02:56 PM) [snapback]431790[/snapback]</div>

Come on! Get Real! I have lived in South Texas for 30 years and it's no worse than the midwest in the summertime. Air conditioning is nice, but it isn't a "have to have" thing. The temp may get hot here in Texas, but there is always a breeze.

 

<div class='quotetop'>QUOTE(local_host @ Apr 28 2007, 12:17 PM) [snapback]431797[/snapback]</div>

Setting A/C to max just makes your situation worse. You have to understand how the Prius works. First, 78-80F in the automatic settings is not actually 78-80F. It actually feels like 73F-75F if you keep the vents on you. When the A/C is on, add 5F against your targeted temperature. When the A/C is off, subtract 5F. Lower the temps a couple more F on the A/C if you have passengers. The A/C is also a guess gauge.

Second, since the Prius's compressor is electric, it means you kept the H/V battery drained so your stop/start engine in traffic just got worse because you never let it hold any of the charge you would've reclaimed from braking. The Prius only charges the battery the minimal it needs in stop-n-go traffic to maximize MPG.

Third, get some ceramic based tinting (or anything that rejects solar IR, not just light) for the windows so the A/C is not working against the green-house effect. Ask your tinter to demonstrate performance with a heat lamp and tint samples.

Fourth, take off your thick clothes. Seems obvious, but I've seen people that don't understand the obvious. Antibiotic soap for example ...

I live in Southern California and I've done this in 2 hours of 100F+ stop-n-go in LA traffic through 50 miles of commute (one way) with A/C set to 79F (78F if temps go above 102F), so I know better than what you're talking about. I have ceramic tinting on from Huper Optik, btw.

ps There's another guy on these forums guy who survived driving out of the Katrina refugee traffic on one tank of gas because he understood when to use the A/C.

 

Does the ICE turn on if you let it "crawl"?

 

<div class='quotetop'>QUOTE(Bob64 @ Apr 28 2007, 02:05 PM) [snapback]431830[/snapback]</div>

Sometimes, but usually only until it gets into the blue bars. If one really doesn't care about the MPG, try putting it into B-mode. It'll keep the engine on (depending on how you enter the mode), but you'll experience a lot of engine braking too.

 

<div class='quotetop'>QUOTE(efusco @ Apr 28 2007, 01:01 PM) [snapback]431791[/snapback]</div>

I concur. That's a pretty silly reason to want to trade in a Prius if you ask me.

To the OP, yes, it's normal when the battery is low. Sounds like he'd rather have it running the whole time and wasting gas.

<div class='quotetop'>QUOTE(local_host @ Apr 28 2007, 12:44 PM) [snapback]431780[/snapback]</div>

It takes a LOT more energy to move a car from a standstill than to sit there idling. http://priuschat.com/index.php?s=&show...st&p=403689 mentions it takes ~300 watts for the Prius to maintain itself. I'm sure this is w/the AC compressor not running. (Even when the AC button is on, the compressor will cycle on/off).

 

The on/off cycling described in the original post is common under the described circumstances and rather upsetting. You lift your foot from the accelerator, the engine turns on, you brake a couple of feet ahead and it turns off, and so on. And, the shudder does not go away as the car ages, mine has 62,000 miles on the odometer and still shakes as good as new.

When this situation happens to me, I usually turn the air conditioner off (I keep it at 75 degrees). If it's too hot or raining, sometimes I step on the brake and press the accelerator half way to keep the ICE running. The battery will charge and the cycling will stop until the battery goes back to pink bars.