Green box and EV light and MPG

[FordDriver49]

I bought my 2010 hybrid in March. Since then I have loved it, loved it, loved it, until about a month ago, when things changed. One day while driving to work I thought it was acting strangely. All the leaves disappeared and it seemed that the engine was on the whole trip. I suspect now that it went into the reconditioning mode. It has about 9500 miles on it. Since then, I have been obsessing on the green box and the EV light, which seems to have changed. For much of my commute, the green box and EV light do not come on at all. The most alarming thing is my average mileage has gone from 39.9 to 35.8. I called to make an appointment with the dealer for this Friday, since I'm convinced something is wrong. The green box comes and goes, and disappears completely for much of my commute. I haven't been able to figure out a pattern, and now I have been obsessed with watching it for the past few weeks that I can't remember how it worked before. I live in Seattle, and while the temperature has dropped, I was generally using the AC in the summer, so I don't think it's the power load. I also see the green box doesn't come on if I turn the heat and accessories off.

I have two questions. 1) Can someone remind me how that power display is supposed to work (green box and EV light)? I have a low confidence in the dealer that I'm seeing so would love some advice. I've read the manual but it basically says if you don't have the green box the engine won't turn off, which isn't that helpful. I'm afraid the dealer will tell me they can't find anything, but I know there's been a big change in the car's behavior since that one day. 2) I'm seeing on the forum that winter driving makes a difference, but over 4 mpg? My normal commute is 22 miles, with some city and mostly highway driving. We have the oxygenated fuel here - don't know if that's national or not.

Thanks for any insight.

[lolder]

Temperature affects mpg to the tune of almost -0.2 mpg per decrease in temp. per degree F. A forty degree drop is worth a drop in mpg of almost 8 mpg. That's in addition to less EV when calling for cabin heat which increases initial ICE operation. Wet roads and head winds are very adverse. You're mileage change is not alarming. After the interior is warm, If the ICE stops below 47 mph while decelerating and at stops, it's probably OK. Comfort permitting, delaying cabin heat requirements until the ICE warms up from driving will help the initial high ICE use in cold weather. That's not much fun. Wet roads are terrible! If you're throwing a lot of spay, it might be -10 mpg!! Make sure you're not in "L". That provides no drive-ability advantage except in very steep or long downhill driving. Check your tire pressure; mine was down 6 psi with cooler weather. Move to Florida! Good luck!

[dogo88]

I've had my FFH since May 2009. It currently has about 17,000 miles. I casually check my mpg at fill up time with miles driven since the last fill up. I consistently get between 36.5 and 38.5 regardless of weather, or season. My commute is about 30 miles round trip, with some stop and go, and some highway speeds. I'm not a hypermiler. I don't have the patience with all the morons whizzing by. So I drive a normal flow with the traffic.

 

The short trip mileage mpg reading you get after every trip is very optimistic. I've gotten 50+ readings. But the real value is when you fill up vs miles driven since last fill up.

 

Just my 2 cents.

 

Dan

[bnajack]

Temperature affects mpg to the tune of almost -0.2 mpg per decrease in temp. per degree F. A forty degree drop is worth a drop in mpg of almost 8 mpg. That's in addition to less EV when calling for cabin heat which increases initial ICE operation. Wet roads and head winds are very adverse. You're mileage change is not alarming. After the interior is warm, If the ICE stops below 47 mph while decelerating and at stops, it's probably OK. Comfort permitting, delaying cabin heat requirements until the ICE warms up from driving will help the initial high ICE use in cold weather. That's not much fun. Wet roads are terrible! If you're throwing a lot of spay, it might be -10 mpg!! Make sure you're not in "L". That provides no drive-ability advantage except in very steep or long downhill driving. Check your tire pressure; mine was down 6 psi with cooler weather. Move to Florida! Good luck!

 

Thanks. This is a very helpful post. How did you derive the -0.2 decrease / degree F? Not questioning this, just curious. I, too have noticed that my mileage drops when I drive in the rain. I don't understand the correlation between wet roads and gas mileage. Heads winds I understand.

[lolder]

Thanks. This is a very helpful post. How did you derive the -0.2 decrease / degree F? Not questioning this, just curious. I, too have noticed that my mileage drops when I drive in the rain. I don't understand the correlation between wet roads and gas mileage. Heads winds I understand.

I've done some tests. It's closer to -0.17. There are lot's of other effects. Speed lowers mpg 0.7 mpg per mph. I think the base line is 45 mpg at 50 mph at 60 degrees F, AC off. One analysis of the wet roads loss is energy required to lift the water 5 ft. in the spray. That calculation seemed off by a factor of ten. Look at this site about Gen 2 Prius's: http://privatenrg.com/. FFH numbers are about 20 % different but magnitude of the effects are similar.

[bnajack]

I've done some tests. It's closer to -0.17. There are lot's of other effects. Speed lowers mpg 0.7 mpg per mph. I think the base line is 45 mpg at 50 mph at 60 degrees F, AC off. One analysis of the wet roads loss is energy required to lift the water 5 ft. in the spray. That calculation seemed off by a factor of ten. Look at this site about Gen 2 Prius's: http://privatenrg.com/. FFH numbers are about 20 % different but magnitude of the effects are similar.

 

Nice link. Thanks.

[MKZ 2011]

Checking that you are not driving in "L" is a possibility and please don't take it as an insult. I did it for about ten miles before I figured it out. Same symptoms

[lolder]

Checking that you are not driving in "L" is a possibility and please don't take it as an insult. I did it for about ten miles before I figured it out. Same symptoms

I've inadvertently driven in "L" several times. It's easy to do as there's not much of a detent between L and D . The only way you'll notice is less EV, more rapid deceleration with foot off the pedal and higher rpms sometimes which may be difficult to hear.

[oldschool1962]

I've inadvertently driven in "L" several times. It's easy to do as there's not much of a detent between L and D . The only way you'll notice is less EV, more rapid deceleration with foot off the pedal and higher rpms sometimes which may be difficult to hear.

 

Whole heartedly agree with Lee here. Thought I had conditioned myself to not allow this to happen after the first 4-5 times but it happened twice in the last few weeks. All it takes is a quick movement with a slight distraction and you're in "L".

[lolder]

On another note about the use of "L", I have found it is possible to force EV during initial warm up before the thermometer turns green in "Empower" display mode by shifting to L for several seconds with foot off the accelerator pedal and then shifting to D. I think this is fooling the software and I'm undecided whether it's advisable.

[FordDriver49]

Thanks for the replies, this was really helpful.

As I suspected, the dealer didn't have any useful information. They drove the car around and called a hotline number. The hotline number said the car was OK. The mechanic didn't have a clue about the hybrid, they haven't been around long enough I guess.

I asked if it's possible to get more information from Ford on mileage and hybrid behavior related to winter conditions, wet roads, temperature. They said they would call the hotline again and call me back. I'll post if I learn anything interesting.

I'm now obsessed enough I think I'm going to set up a spreadsheet to track my commute mpg, including the temperature, road conditions, etc.

As far as driving in low, this is the first automatic I've ever owned, so I still look ever time I shift, and still try to step on the clutch once in awhile. I did catch my friend putting it in low however, when he drove my car.

And I'd love to move to Florida, you guys have any jobs down there? They're few and far between up here.