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Old 11-13-2012, 01:09 PM   #1 (permalink)
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Location: Pennsylvania, USA
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Default Inconsistent MPG + Impact of Winter Gas

Greetings, all...

Bought a nearly-new 2012 Insight LX in August (8,300 mi.) and am generally delighted with the car.

My MPG has been wildly inconsistent from tank to tank though. First refill = 48 MPG. Two tanks later = 33 MPG, with NO major difference in my driving, terrain, AC usage or outdoor temps. Eco button on vs. off seems to make no measurable difference in MPG, either.

Now, 90 days/1,700 mi. later, with approx. 10,000 miles on the car, and Winter temps here in central Pennsylvania, I'm down to about 27-29 mpg, combined. Smart local Honda service manager says it's the switchover to winter gas formulations in the mid-Atlantic US, but I'm not 100% satisfied. (FYI, I'm using only high-quality gas - Exxon, Shell, mostly, but MPG is still ll over the map and trending downward, overall.)
  1. Is this consistent with your experiences, esp. if you live in the Northeastern or Mid-Atlantic US?
  2. Any other possible explanations for the inconsistent and disappointing MPGs? Service manager says there's nothing to tune or re-calibrate.
  3. Any recommendations to get those 48+ MPG's again that I experienced with the first refill?

Thanks in advance. —Mike Russell/planetrussell
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Old 11-13-2012, 03:00 PM   #2 (permalink)
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Welcome aboard!!! Yes, everything effects mpg in a hybrid. Have you checked your tire psi? Have you hit anything that could of messed up the front alignment? Have you felt the tires to see if they are feathering? Have you tried regular gas from BP? Do you use the heater, defroster or had a new stereo installed?

Fuel can effect it by 5mpg, tire psi, a good 10 psi. A low 12 volt battery also plays a role, however you will see less assist and more or constant regen on the hybrid meter if its that.

Although Ive managed to break 100 mpg with a phev kit, I found when my starter battery needed to be replaced the best I could do was like 48 mpg.

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Old 11-13-2012, 04:52 PM   #3 (permalink)
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The 27-29mpg sounds low based on my experience with my 2010 I2. I have no idea what is the reason.

One thing you should check is that the car has the latest "computer" updates. One of the updates if I remember correctly lowered the mpg of the car. A later one fixed this problem.

Speaking of the effect of updates on mpg, I wanted to give some feedback on how the updates on our I2 affected the mpg of the car. My wife has the i2 most of the time up in Oregon (where was have a place). In a recent service in the dealer in Southern Oregon she had them install the latest computer updates. I finally got to drive the car just in the last couple of days as she drove down to our apartment in Southern Cal. As some of you may remember I have a route that I use to test the mpg of the car (from Santa Clarita to West LA, Pico Blvd all on interstate I5). My best mpg on this route was 72 mpg and the next best was 68mpg. I only ever achieved above 70mpg once. Well on this last run I got 79.9 mpg from the readout. This was not using econ-mode! Usually the readout on our car is around 3% optimistic. (The 72mpg is not corrected for this). So I was very surprised. I noticed that the car never did a regen going up hill as was a problem prior to the software updates. But more interesting is the fact that on the way back we got caught in a horrendous traffic jam on I5. It took us a half an hour to go 2 miles. Even so we ended up with an average of 51mpg for around 70 miles of driving (going North on I5 the mpg is considerably lower do to the increase in elevation). I have yet to determine if the update affected the accuracy of the readout. Assuming that it is still around 3% than this would indicate a huge boost in mpg. I can confirm that the tire pressure was the same as before (37psi cold) and that the wear on the tires was very slight compared to the time I achieved 72mpg. The temperature was 61F and I do believe the wind may have been blowing North to South. So this may have been close to ideal conditions. But an increase of 10% over my best mpg is quite dramatic.

To recap what we have done to the car. The car is not lowered (which would explain an increase in mpg) and we have added over the years a K&N filter, rear PT sway bar, Cusco type 2 front lower arm bar and front strut tower bar and Nokian WRG2 tires (185/60R15). All the above changes were already made when I got the 72mpg.
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Old 11-13-2012, 04:59 PM   #4 (permalink)
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1700 miles in 90 days is only 6800 miles a year... what's the length of your commute? If it's 4 miles one way in in-town driving, the engine is probably never getting warmed up before you get there and so the cold weather is killing your mileage.

If this is the case, consider installing/having installed an engine block heater and I bet your morning commute mileage will jump way up.

2004 Honda Civic Hybrid "Eeyore" @ 49 mpg
-MaxIMA, OBDIIC&C, IMAC&C, Lower grill block

RIP 2000 Insight, 40k miles @ 69.2 mpg
2000 Insight, AKA "The Basket Case" or "The Go Pod" @185k miles @ 63.5 mpg
-IMAC&C, OBDIIC&C, Scott's aero panel, grid charger, cheapo sound system
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Old 11-14-2012, 12:36 AM   #5 (permalink)
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I concur with planetrussel and blaming everything on winter temps. I had 50 mpg on the first days that I drove the car, and the tires were partly deflated.

Then I filled up the tank, got the tires to 44 psi and that's when the cold/humidity settled in. Heater/defroster are almost always on... Also I have a very short commute home-workplace so I'm doing 33 mpg at best right now.

But I'm thoroughly enjoying this car because a) it looks awesome, no one else seems to have it in this European car country, b) it's fun to drive, c) it's silent and relaxing compared to my 1991 Civic. Now I'm just hoping that the Spring will increase my mpg...
2012 Insight EX - Oct. 30th 2012
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Old 11-14-2012, 02:11 PM   #6 (permalink)
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The latest updates do seem to have greatly reduced the number of uphill regens I see. I used to get an uphill regen most mornings on my way to work but not one since the update.

On my way home I have a 2 mile uphill stretch and do still see the occasional uphill regen there though.

No real improvement in fuel economy that I've noticed but I did get the update just as the weather was turning colder.

Sent from my MB526 using AutoGuide.Com Free App
2010 Honda Insight ES 1.3 IMA (UK)
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Old 11-16-2012, 02:02 AM   #7 (permalink)
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Many thanks, all.

Question: Is there any way to view the various software/firmware versions from the MID display or someplace, or must I take my 2012 Insight into the dealer to determine whether or not I'm current? Maybe I'm overlooking it, but I wasn't able to find the answer to this elsewhere. Thanks in advance.
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Old 11-16-2012, 08:15 PM   #8 (permalink)
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Default Software updates

I had these updates done a week or so ago at the dealer on my 2010. It was not enough to go in and ask for them as they are not listed as 'recall' items, only the roof strips are. When I mentioned the software updates, and they were not listed on the recall items, the service desk guy asked "Is there a specific problem". This is code for "we cannot install them unless there is a problem". I responded with the well known problem of the long delay in the CVT engaging when cold, which I actually hoped the updates would fix as I read on this site one of them was for the CVT. At which point they nicely installed 3 software updates under warranty even though my car is over the warranty period. They had no idea what the updates do, there was no documentation or even names of the updates.

After driving the car for a week I see no discernible difference at all in the way the car behaves, and I pay attention to what the car does. It certainly has not fixed the CVT engage delay. It may have reduced its amount of regen on hill climb, but it still seems to do this. There has been no dramatic effect on MPG, if anything mildly negative, but this could also be the colder weather. I am surprised when I read that others have seen positive observable effects of these updates.

The 'key on' while holding the recirculate and auto buttons to get into the diagnostic mode shows the same software rev of the climate control (Rev C). I do not know how to display the versions of the other software modules.

If you want these updates, my advice to you is to go to the dealer, mention the updates, and the CVT delay issue and see what happens, it worked for me. It really only generated a warm feeling that I had the updates, as the car behaves the same. You may get lucky and they'll fix the CVT delay
2010 EX Sky Blue since 11/2/09
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Old 11-16-2012, 10:38 PM   #9 (permalink)
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Have you had the CVT fluid changed?
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