ICE has started shutting down at low temps

storm petrol · 02-28-2006, 10:25 PM

All winter my '05 has stubbornly refused to shut down at stops until thoroughly warmed up. Adding the block heater helped but it still took some driving before it would shudder to a stop.

Three days ago, at very close to 0 F, it started shutting down almost immediately, at the first stop sign a hundred yards down the road. This has continued in temperatures around 14 F, 18 F, even after being parked for hours without the heater.

At first I wondered if it was stalling in the bitter cold. However, it seems to be actually shutting down! It starts right up when asked and goes merrilly along. And I can tell by the low MPG when it starts up and especially when coasting (not getting 99 mpg) that the engine is not somehow magically warm and running efficiently.

I am pleased not to be wasting fuel while waiting at stops but am concerned about the change.

Anyone have any ideas what is going on here?

Thanks,

storm petrol

jbarnhart · 03-01-2006, 03:21 AM

I don't have the super cold temps here in California, but I notice my ICE shuts down from the start, but only if my climate control is off. If I'm running the AC/heater it doesn't shut down when cold. Are you running your heater?

storm petrol · 03-01-2006, 06:57 AM

Minimally, but it is usually going to be on low fan, set for 65F (lowest it will go) when it is between 0and 20 F!

I will play with that idea.

Thanks!

storm petrol

paprius4030 · 03-01-2006, 09:43 AM

I too have noticed this when the heat is off. I usally leave the a/c function off but still in the auto mode for controlling them temp. When set this way the ICE still runs at stops while warming up, I only noticed the ICE shutting off early during warm up with the heat off completly. Maybe somebody changed how your heat control is set?????

priusham · 03-01-2006, 09:56 AM

Yeah... if the heat is OFF or set to AUTO and the cabin has reached whatever temp you've set it at, the ICE will *usually* shut down at stops.

The engine still needs to be warm, as well as the whole exhaust system.

If the ECM *thinks* the engine needs to be on, it'll be on. Trust it, it's got way more information coming into it than you or I get to see.

daniel · 03-01-2006, 10:17 AM

In Phase 2 (if I remember rightly) the engine will shut down at stops much more readily than it will do in Phase 3. I have no idea why this is. It seems counterintuitive and even dumb. But I've observed it, as have others. This means that once the engine has warmed up a bit, it shuts down readily, but then as it warms up some more it is very reluctant to shut down, and then, when fully warmed up, it shuts down readily again.

An EV switch will allow you to shut off the engine once it has warmed up just a bit. But note that I think the EV must be disengaged for the car to go into Phase 4 operation. So you can use the EV switch to stop the engine as you approach stop lights, but once it is fully warm you should allow the engine to remain on at a stop, so it can stop (reluctantly!) on its own. Once it's in Phase 4 operation you can resume using the EV switch as you see fit.

This applies to the '04. I have no idea if the parameters have changed for the '06.

storm petrol · 03-03-2006, 07:17 AM

This vehicle continues to shut down at stops while cold. It is also much less reluctant to run in EV mode. Even after parked for hours at ambient temps in the twenties it starts off in EV. After only a few moments of driving, I can get it up to 30 mph before the ICE kicks in.

It is slightly more inclined to do this if the heating/cooling system is shut down. However, it will do it with the system engaged.

It is behaving the way I would prefer it to behave. However, it seems to be ignoring its own requirement for the converter to warm up. Or reading my mind about wishing it would stop wasting gas at lights and to please use some of that charge in the battery to move us down the road.

But it is a significant change.

Should I be concerned?

Anyone have any further ideas?

Thanks,

storm petrol

02-28-2006, 10:25 PM	#1
storm petrol Join Date: Jun 2005 Location: 44 degrees, 42 minutes North; 73 degrees, 29 minutes West. Posts: 62 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	All winter my '05 has stubbornly refused to shut down at stops until thoroughly warmed up. Adding the block heater helped but it still took some driving before it would shudder to a stop. Three days ago, at very close to 0 F, it started shutting down almost immediately, at the first stop sign a hundred yards down the road. This has continued in temperatures around 14 F, 18 F, even after being parked for hours without the heater. At first I wondered if it was stalling in the bitter cold. However, it seems to be actually shutting down! It starts right up when asked and goes merrilly along. And I can tell by the low MPG when it starts up and especially when coasting (not getting 99 mpg) that the engine is not somehow magically warm and running efficiently. I am pleased not to be wasting fuel while waiting at stops but am concerned about the change. Anyone have any ideas what is going on here? Thanks, storm petrol __________________ 2005 Driftwood Pearl/Package #5. CAN-view; BT Stiffening Plate; Block heater; Fumoto drain valve; Amsoil 0-30W and filter; Zaino. 49 mpg @ 8,000 miles.

03-01-2006, 10:17 AM	#6
daniel Cat Lovers Against the Bomb Join Date: Feb 2004 Location: Spokane, WA Posts: 14,311 My Car: 2004 Prius Model: Package: #6 Thanks: 453 Thanked 1,326 Times in 928 Posts Friends: 0	In Phase 2 (if I remember rightly) the engine will shut down at stops much more readily than it will do in Phase 3. I have no idea why this is. It seems counterintuitive and even dumb. But I've observed it, as have others. This means that once the engine has warmed up a bit, it shuts down readily, but then as it warms up some more it is very reluctant to shut down, and then, when fully warmed up, it shuts down readily again. An EV switch will allow you to shut off the engine once it has warmed up just a bit. But note that I think the EV must be disengaged for the car to go into Phase 4 operation. So you can use the EV switch to stop the engine as you approach stop lights, but once it is fully warm you should allow the engine to remain on at a stop, so it can stop (reluctantly!) on its own. Once it's in Phase 4 operation you can resume using the EV switch as you see fit. This applies to the '04. I have no idea if the parameters have changed for the '06. __________________ Daniel Primary car: 2010 Tesla Roadster. Range: 245 miles on a charge. Zero to sixty: 3.9 seconds. Torque: 273 foot-pounds. Horsepower: 288. 100% electric @ 2 cents per mile. Gas guzzler for road trips or when I park at the airport: 2004 Prius. "If voting changed anything, they'd make it illegal." -- Emma Goldman "Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think long and hard before starting a war." -- Otto von Bismarck

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03-01-2006, 03:21 AM	#2
jbarnhart Senior Member Join Date: Jan 2004 Location: Santa Clara, CA Posts: 629 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 1	I don't have the super cold temps here in California, but I notice my ICE shuts down from the start, but only if my climate control is off. If I'm running the AC/heater it doesn't shut down when cold. Are you running your heater?

03-01-2006, 06:57 AM	#3
storm petrol Join Date: Jun 2005 Location: 44 degrees, 42 minutes North; 73 degrees, 29 minutes West. Posts: 62 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Minimally, but it is usually going to be on low fan, set for 65F (lowest it will go) when it is between 0and 20 F! I will play with that idea. Thanks! storm petrol

03-01-2006, 09:43 AM	#4
paprius4030 Senior Member Join Date: Aug 2004 Location: Pocono's, Pa. Posts: 1,761 My Car: 2010 Prius Model: II Package: #2 Thanks: 61 Thanked 60 Times in 54 Posts Friends: 3	I too have noticed this when the heat is off. I usally leave the a/c function off but still in the auto mode for controlling them temp. When set this way the ICE still runs at stops while warming up, I only noticed the ICE shutting off early during warm up with the heat off completly. Maybe somebody changed how your heat control is set?????

03-01-2006, 09:56 AM	#5
priusham Join Date: Jul 2004 Location: Michigan - land of everlasting snowflake icon! Posts: 525 My Car: Model: Package: Thanks: 0 Thanked 1 Time in 1 Post Friends: 0	Yeah... if the heat is OFF or set to AUTO and the cabin has reached whatever temp you've set it at, the ICE will usually shut down at stops. The engine still needs to be warm, as well as the whole exhaust system. If the ECM thinks the engine needs to be on, it'll be on. Trust it, it's got way more information coming into it than you or I get to see.

03-03-2006, 07:17 AM	#7
storm petrol Join Date: Jun 2005 Location: 44 degrees, 42 minutes North; 73 degrees, 29 minutes West. Posts: 62 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	This vehicle continues to shut down at stops while cold. It is also much less reluctant to run in EV mode. Even after parked for hours at ambient temps in the twenties it starts off in EV. After only a few moments of driving, I can get it up to 30 mph before the ICE kicks in. It is slightly more inclined to do this if the heating/cooling system is shut down. However, it will do it with the system engaged. It is behaving the way I would prefer it to behave. However, it seems to be ignoring its own requirement for the converter to warm up. Or reading my mind about wishing it would stop wasting gas at lights and to please use some of that charge in the battery to move us down the road. But it is a significant change. Should I be concerned? Anyone have any further ideas? Thanks, storm petrol