Weird MPG

DanMan32 · 03-03-2005, 12:01 PM

Tony, running the engine to operate the A/C compressor? The compressor is electric on the THSII. The engine would only operate to charge the HV battery. Now running the engine to get heat for the cabin, THAT I could understand.

**TonyPSchaefer** · 03-03-2005, 12:35 PM

Half right, half wrong.
Six of one, half dozen of the other.

Thanks for keeping me straight, Dan. If only to make sure that I'm not randomly confusing people.

exces6 · 03-03-2005, 10:37 PM

Thanks everyone. Should I change the tire pressure from what it was when I got the car? If so, what should it be?

Kyle Pehrson · 03-03-2005, 11:15 PM

Evan
We are at 6000 feet Sorry I forgot that most everyone else is not. The gas pumps here are mostly 88. some cust that live in Park City have to run 91 or they will ping
if it is not pinging don't go up. I could get better gas mileage in summer if I used 91 than if I used 88. In the winter it will not make a difference at all. I have never had a bit of trouble.

Kyle Pehrson · 03-03-2005, 11:26 PM

Tire Pressure is 35 psi on front & 33 on the rear some people set them higher to improve gas mileage but you will sacrifice some handling.

**TonyPSchaefer** · 03-04-2005, 10:22 AM

http://www.priuschat.com/forums/mileage-ve...ure-vt1179.html
http://www.priuschat.com/forums/dealer-had...005-vt5497.html
http://www.priuschat.com/forums/the-cant-g...lub-vt2975.html
http://www.priuschat.com/forums/mpg-droppe...kup-vt4648.html

canuckican · 03-04-2005, 11:09 AM

just a quick question about Dan's response to Tony's response...

Quote:

Tony, running the engine to operate the A/C compressor? The compressor is electric on the THSII. The engine would only operate to charge the HV battery. Now running the engine to get heat for the cabin, THAT I could understand.

It is the "only operate to charge the HV battery" statement I have a question with. It seems to me that as I drive around in the below freezing weather for the last several months, the ICE runs during the first 10 minutes (at least) to get itself warm and then runs to keep itself warm as it cools just by driving through cold air. Regardlesss of whether cabin heat is on or not, I do believe the ICE will be running (intermittently) to maintain this high engine temperature. This seems to be consistent with low emissions, doesn't it? The engine wants to be warm to operate most efficiently.

I would posit that is what exces6 is seeing/experiencing - not low tire pressure. Once again, it's cold out there folks. You're operating an engine. Performance does have something to do with ambient temperature.

DanMan32 · 03-04-2005, 12:31 PM

Yes, that would be to produce HEAT, not to run the AC compressor. If you are sitting there in park, the engine will not run to maintain its temperature (other than during initial turn on), but rather only to maintain HV charge. I had this experience when I first got the car in August, running the AC while playing with the NAV. Engine ran only to keep SOC at 2 bars. Now once you get going, MPG is low to warm the engine/catalytic, and to bring SOC to 6 bars. I guess Toyota doesn't figure running the engine for 30 seconds to maintain SOC is long enough to cause an emissions issue, especially since this will not be a frequent occurance.

Even while driving, when I ran into stop and very slow traffic, the battery ran down. ICE started only for about 30 seconds, and usually only started if I moved. When I stopped, it stopped, but seemed reluctant.

03-03-2005, 10:37 PM	#13
exces6 Join Date: Aug 2004 Location: Houston, TX Posts: 97 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Weird MPG Thanks everyone. Should I change the tire pressure from what it was when I got the car? If so, what should it be?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
A Weird Suggestion?	Mystery Squid	PriusChat Website Questions	28	05-04-2007 12:42 PM
so this is weird	Conine	Prius Technical Discussion	7	03-27-2007 12:33 AM
Weird Al	Tadashi	Fred's House of Pancakes	17	03-21-2007 05:36 PM
Well, that's weird	onerpm	Care, Maintenance and Troubleshooting	12	01-03-2007 05:00 PM
This seems weird	4chi	Prius Main Forum	14	10-23-2006 05:24 PM

03-03-2005, 12:01 PM	#11
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Tony, running the engine to operate the A/C compressor? The compressor is electric on the THSII. The engine would only operate to charge the HV battery. Now running the engine to get heat for the cabin, THAT I could understand.

03-03-2005, 12:35 PM	#12
TonyPSchaefer Ruler of Omicron Persei 8 Join Date: May 2004 Location: Far-North Chicagoland Posts: 8,434 My Car: 2004 Prius Package: #9 Nominated 4 Times in 2 Posts TOTM Awards: 0 Friends: 16	Half right, half wrong. Six of one, half dozen of the other. Thanks for keeping me straight, Dan. If only to make sure that I'm not randomly confusing people.

03-03-2005, 11:15 PM	#14
Kyle Pehrson Prius Master Tech Join Date: Feb 2005 Location: S.L.C. Utah Posts: 122 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Evan We are at 6000 feet Sorry I forgot that most everyone else is not. The gas pumps here are mostly 88. some cust that live in Park City have to run 91 or they will ping if it is not pinging don't go up. I could get better gas mileage in summer if I used 91 than if I used 88. In the winter it will not make a difference at all. I have never had a bit of trouble.

03-03-2005, 11:26 PM	#15
Kyle Pehrson Prius Master Tech Join Date: Feb 2005 Location: S.L.C. Utah Posts: 122 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Tire Pressure is 35 psi on front & 33 on the rear some people set them higher to improve gas mileage but you will sacrifice some handling.

03-04-2005, 10:22 AM	#16
TonyPSchaefer Ruler of Omicron Persei 8 Join Date: May 2004 Location: Far-North Chicagoland Posts: 8,434 My Car: 2004 Prius Package: #9 Nominated 4 Times in 2 Posts TOTM Awards: 0 Friends: 16	http://www.priuschat.com/forums/mileage-ve...ure-vt1179.html http://www.priuschat.com/forums/dealer-had...005-vt5497.html http://www.priuschat.com/forums/the-cant-g...lub-vt2975.html http://www.priuschat.com/forums/mpg-droppe...kup-vt4648.html

03-04-2005, 12:31 PM	#18
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Yes, that would be to produce HEAT, not to run the AC compressor. If you are sitting there in park, the engine will not run to maintain its temperature (other than during initial turn on), but rather only to maintain HV charge. I had this experience when I first got the car in August, running the AC while playing with the NAV. Engine ran only to keep SOC at 2 bars. Now once you get going, MPG is low to warm the engine/catalytic, and to bring SOC to 6 bars. I guess Toyota doesn't figure running the engine for 30 seconds to maintain SOC is long enough to cause an emissions issue, especially since this will not be a frequent occurance. Even while driving, when I ran into stop and very slow traffic, the battery ran down. ICE started only for about 30 seconds, and usually only started if I moved. When I stopped, it stopped, but seemed reluctant.