Sudden mileage drop

HenryE · 03-17-2006, 11:51 PM

'04 with all the goodies, 30k miles, no problems, S Calif weather. The mileage has jumped around from 44 to 47, averaging 45.5 for the last year or so.

Just had the 30k check, and while the car was at the dealer the ECU was 'reflashed'. A couple of days later the weather was warm and I saw a temperature warning. I have the Scangauge installed, so switched one readout to water temp and saw 245degF, coming down rapidly. Dealer said 'if it repeats, bring it in'.

At about that point I had four Goodyear Assurance Comfortred tires installed - they're quier and handle well. Fuel consumption seemed ok, but overnight it fell like a rock and for the last two tanks it's averaged 36.7.

?????

tripp · 03-17-2006, 11:57 PM

Hmm... check yer tyres. Perhaps the pressure in one or more of them is really low due to a slow leak. Others have posted that as a cause of a sudden drop in mpg. Perhaps the tyres weren't installed properly?

HenryE · 03-18-2006, 10:07 AM

Quote:

Originally posted by tripp@Mar 17 2006, 11:57 PM
Hmm... check yer tyres. Perhaps the pressure in one or more of them is really low due to a slow leak. Others have posted that as a cause of a sudden drop in mpg. Perhaps the tyres weren't installed properly?

[snapback]226320[/snapback]

The installer used 35F 32R, but I pumped them up to 40F 36R. I rechecked after noting the drop in mpg and there's no loss in pressure. When I examined the tires they appeared to be installed properly.

I wonder if anyone else who had the ECU flashed had such a problem.

hawkjm73 · 03-18-2006, 10:39 AM

For reference, there should be a 2psi difference between the front and back tires.

DaveinOlyWA · 03-18-2006, 10:42 AM

about that reflash. since ive had mine done, i have gone to max discharge of zero (means that regen can no longer add charge to the battery) with SOC at 75%.

the limit is supposed to be 80% but i know of two occasions (81 and 83%) that i exceeded that limit. now since the flash, i seem to maintain EV longer in the lower SOC ranges but wondering if anyone else with CANVIEW has noticed this as well??

was not going to mention this this early since some seem to think the temp of the traction battery matters so was gonna wait till summer to see if this persists.

twdusa · 03-19-2006, 01:17 AM

Quote:

Originally posted by HenryE@Mar 17 2006, 11:51 PM
'04 with all the goodies, 30k miles, no problems, S Calif weather. The mileage has jumped around from 44 to 47, averaging 45.5 for the last year or so.

Just had the 30k check, and while the car was at the dealer the ECU was 'reflashed'. A couple of days later the weather was warm and I saw a temperature warning. I have the Scangauge installed, so switched one readout to water temp and saw 245degF, coming down rapidly. Dealer said 'if it repeats, bring it in'.

At about that point I had four Goodyear Assurance Comfortred tires installed - they're quier and handle well. Fuel consumption seemed ok, but overnight it fell like a rock and for the last two tanks it's averaged 36.7.

?????

[snapback]226317[/snapback]

OK, I hate to say this , but it happened to me. Double check that your foot activated PARK BRAKE is fully disengaged. I rode around for two days wondering why my MPG had fallen so badly untill I realized that my foot park brake pedal was depressed about one quarter of the way! OH my, completely released and the mpg was back to normal. Probably not your problem but worth a double check anyway!

HenryE · 03-19-2006, 01:37 AM

Quote:

Originally posted by twdusa@Mar 19 2006, 01:17 AM
OK, I hate to say this , but it happened to me. Double check that your foot activated PARK BRAKE is fully disengaged.

[snapback]226800[/snapback]

Right -- I checked and it's ok -- thanks.

Using the RESET button to permit checking short stretches, I've checked conditions where I really know what the mileage should be - and it's definitely much worse. There's a stretch of road that in the past consistently generated high 50s at 45mph. It's now mid 40s.

I wish the ECU flash and new tires were a few weeks apart so I would have a better idea of where the culprit is.

richard schumacher · 03-19-2006, 02:29 PM

Quote:

Originally posted by HenryE@Mar 19 2006, 01:37 AM
Right -- I checked and it's ok -- thanks.

Using the RESET button to permit checking short stretches, I've checked conditions where I really know what the mileage should be - and it's definitely much worse. There's a stretch of road that in the past consistently generated high 50s at 45mph. It's now mid 40s.

I wish the ECU flash and new tires were a few weeks apart so I would have a better idea of where the culprit is.

[snapback]226805[/snapback]

Kinda sounds like the tires. Comfort versus economy.

03-18-2006, 10:42 AM	#5
DaveinOlyWA Opps !! I Did it Again!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 9,371 My Car: 2006 Prius Package: #4 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 4	about that reflash. since ive had mine done, i have gone to max discharge of zero (means that regen can no longer add charge to the battery) with SOC at 75%. the limit is supposed to be 80% but i know of two occasions (81 and 83%) that i exceeded that limit. now since the flash, i seem to maintain EV longer in the lower SOC ranges but wondering if anyone else with CANVIEW has noticed this as well?? was not going to mention this this early since some seem to think the temp of the traction battery matters so was gonna wait till summer to see if this persists. __________________ My 2006: Last tank 510.3 miles @51.5 pump (53.3 computer) 6.91 cpm winter mpg 50.78 summer mpg 54.59 lifetime: 31155.2 miles 52.98 mpg pump (54.25 mpg computer) 5.78 cpm My 2007 Zenn Driven 5152 miles, 2.10 cpm/ 170 mpg (at $3.56/gal), 3.82 miles/ Kwh Savings over my Prius $275.84 The Corolla...514.96 The REAL SAVINGS from not driving Corolla 604.39 +Prius= 880.83 (excludes maintenance costs...would be unfair to ICE vehicles) My Plate: DUALPWR (Dual Power)

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03-17-2006, 11:51 PM	#1
HenryE Join Date: Jan 2006 Posts: 5 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	'04 with all the goodies, 30k miles, no problems, S Calif weather. The mileage has jumped around from 44 to 47, averaging 45.5 for the last year or so. Just had the 30k check, and while the car was at the dealer the ECU was 'reflashed'. A couple of days later the weather was warm and I saw a temperature warning. I have the Scangauge installed, so switched one readout to water temp and saw 245degF, coming down rapidly. Dealer said 'if it repeats, bring it in'. At about that point I had four Goodyear Assurance Comfortred tires installed - they're quier and handle well. Fuel consumption seemed ok, but overnight it fell like a rock and for the last two tanks it's averaged 36.7. ?????

03-17-2006, 11:57 PM	#2
tripp Which it's a 'ybrid, ain't it? Join Date: Oct 2005 Location: Denver, CO Posts: 3,431 My Car: 2005 Prius Package: #3 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 2	Hmm... check yer tyres. Perhaps the pressure in one or more of them is really low due to a slow leak. Others have posted that as a cause of a sudden drop in mpg. Perhaps the tyres weren't installed properly?

03-18-2006, 10:39 AM	#4
hawkjm73 Senior Member Join Date: Apr 2005 Location: Phoenix, Arizona Posts: 246 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	For reference, there should be a 2psi difference between the front and back tires.