Hybrid mpg in HOT Weather

[lolder]

Car was parked in the sun and it was around 5:00 pm in the afternoon. Temp showed 116F in the parking lot. I always use the AC in recirculation mode for maximum cooling. The HVB fan is working.

 

The only thing I noticed before it died was that the engine was running a little rough from a dead start which it always would do when the temps would get over 110. The only warning I received was a pull over safely one. No other messages.

 

I though the amount of reconditioning seemed abnormal. They did do a full cell check on the HVB and it was passed. One thing the tech noticed is that my windshield sunshield that I store in the trunk was partially blocking the battery vent in the trunk which could have caused overheating. Removed the sunshield from the trunk since I rarely use it.

 

Noticed after the updates were done that the engine no longer runs rough on starts when over 110.

 

Jim

Sounds like it had heat stroke. Try to park in the shade. If that is not possible, consider a car cover. When I got my FFH, I had to park a nice 2004 Avalon with leather outside in the Florida sun. I bought a slightly reflective car cover for about $130 that goes on and off in about a minute. In 90 deg. temperature, it lowered the inside temperature from 140 to 97 !! After 2 years, it's starting to need restitching but it's a consideration.

[VonoreTn]

My full mileage record is attached, for the first 56,000 miles. Both actual mileage based on gas fill-up data and what the FFH computer said my mileage was for that tank of gas. In general the low numbers were in cold weather, high speed driving (>70mph), or going up long continental grades.

[lolder]

Can you give us the average difference between two calculations?

[VonoreTn]

Can you give us the average difference between two calculations?

 

I track that too. The average over statement of FE by the FFH computer versus actual based on fill-up data is 0.28 mpg for all 115 fill-ups. Some higher, some lower. Usually the computer is pretty darn close, and definitely giving you good feedback.

 

Off topic digression: I always just add one click off of gas after the first automatic clicks off occurs. I have had bad experiences with over clicking the fill-up process with my Daughter's vehicle, if you do that to the point of getting gas in the vent hole near the cap, you can saturate the evaporative emissions system, which is only designed to slowly deal with fumes, not raw gas, and then your vent won't work, and you can get an early click off before fill-up is complete. And the dealers just can't deal with fixing it, too complicated and expensive. Opening the vent to air would fix it, but then in a roll-over accident fuel would be leaking, so you do not want to do that. Bottom line, don't keep clicking the gas nozzle trigger once it is full.

[lolder]

That's a lot closer than my somewhat less rigorous calculations. I figure a car computer number about 1 mpg high and that's after correcting for an odometer that is about 2 % low. Even though we're talking only about a few percent, I'm surprised there is a difference from car to car. I think they're measuring injector on time and wheel turns. I can understand a difference in mpg but not differences in accuracy of measuring it.

[VonoreTn]

I get my biggest deviations between computer and fill-up data on road trips sometimes involving obviously poorly maintained pumps. Often a low or high fill-up mpg is offset by the next fill-up, since maybe a nozzle clicked off too soon. But the deviation still goes into my calculation record. Then there is the variation of vehicle angle to level when filling up. The computer record would be independent of fill-up abnormalities.

[lolder]

I did some mileage tests recently. At 45,000 miles, the car seems to get 2 mpg more at 50 mph than it did three years ago when new. I think 1 mpg was from about 5 psi higher tire pressure and 1 mpg from break-in. That's a pretty small difference but still a little more than the experimental error. At 93 d. F., it got 53.5 mpg with the AC off and 49.7 mpg with the AC on. Tests were done with stabilized HVB levels and cabin temps in both directions on a level sea level smooth road. These are computer readings that are about 2 % high.

[NDallas40]

Here in Texas, we run the AC on all our vehicles about 11 months out of the year. We basically leave the air and radio always on. In 32,000 miles of 50/50 mix of highway and city miles, our FFH shows 34.1 cumulative mpg on the gauge. That pretty much jives with my own records. We keep a log. We've never got even close to 40 on any single tank of fuel. Our best was 37.2 during a rare cool Winter month. That is almost 5 mpg lower than it was advertised when new in 2010. That is a HUGE difference. When I get a free minute or two, I'm going to start a class-action lawsuit regarding the disparity between the advertised and actual mpg on the FFH. I've heard of similar suits against Honda and Hyundai which were successful, though I haven't actually verified these reports. Besides, my neice is a young, motivated lawyer who gives me great rates.

[lolder]

At fueleconomy.gov:

http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=26405&id=30373&id=31388

53 2010-11-12 FFH's got about 38.5 mpg