| zafer |
| I put in a new battery 2 weeks ago. The car was without power much longer than I expected cause I couldn't get a good grip on the old battery to take it out. Anyway, when I powered back up, the navi, radio etc., all had reset (this didn't happen when I installed hids, the battery was only disconnected for a few seconds then). So after system reload, and initialization, etc, etc, the trip comp. is now logging lower mpg's ??? Does something else also need recalibrating? :confused: |
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| ryandinan |
Hey zafer -
My X was in the repair shop for over a month after my accident. They had the doors open most of the time, and never disconnected the battery. Needless to say, they killed it in the process.
Since they have replaced it, I've noticed significantly LOWER MPG. I was going to ask about this as well, but I wrote it off to cold weather and lots of wind around here...
For comparison, on our typical weekly routine, we do 70% highway, 30% city driving. We would always average around 20-21 MPG using 93 octane gas.
Now, the same driving routine nets us barely 18mpg - in fact we struggle to get that. We are not driving the vehicle any differently (not speeding or accelerating any harder than we normally do). Now, Im certain that the extreme cold we've had over the last couple months has had a negative effect on the mpg, but I wasn't expecting 2-3mpg differences (almost 15% decrease).
I was wondering if the X has a "learning curve" that runs for so many miles, before it optimizes performance for the driving style/habits of the driver? Since the battery was dead, Im sure all this information was cleared out of memory. I just wouldn't think that it would take so long to re-establish optimal performance - after all, it's been at least a thousand miles since the battery was changed out...
Anyone have any ideas?
Thanks!
-Ryan |
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| zafer |
quote:
Originally posted by ryandinan
Since the battery was dead, Im sure all this information was cleared out of memory.
My trip history (1 current and 1 previous), as well as all saved addresses, locations etc. were all retained. I didn't loose any of it :) , which was a BIG relief! I was pretty sure they were going to be all wiped out when I saw the navi clean boot, load the system, and initialize, and tell me to make sure the car was parked outside with a clear view to the sky, and not to turn off the ignition for 30 mins. |
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| ryandinan |
Is there a learning period that the X goes through when the memory gets cleared? If so, can you expect lower mpg's during this process? Also, how long does this process take?
Thanks!
-Ryan |
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| taidumei |
| Before I had the battery replaced on my 03 MDX, the mpg was about 17to 19 (I do mostly city drive, about 10 miles per day). After the battery replacement, the mpg was about 11 to 13 (I was like :eek: ). It has been a month, and the mpg is going up to 15 now. My boyfriend told me mpg has nothing to do with the battery but this is what happened............ |
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| G. COLTON |
quote:
Originally posted by taidumei
Before I had the battery replaced on my 03 MDX, the mpg was about 17to 19 (I do mostly city drive, about 10 miles per day). After the battery replacement, the mpg was about 11 to 13 (I was like :eek: ). It has been a month, and the mpg is going up to 15 now. My boyfriend told me mpg has nothing to do with the battery but this is what happened............
I would listen to your boyfriend. He knows what he is talking about.
I guess that it is possible that there is something programmed into the computer that could be lost if there was total power failure for some period of time. However, I doubt it.
If it was some type of "learning" that the computer does, then your MPG would significantly improve, up to some limit, as you drive your new vehicle. I had no such experience when my MDX was new. The mpg has varied very little, depending upon my driving and conditions, since it was new.
G |
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| ryandinan |
So any idea then, why I saw such a mpg decrease after the vehicle was without power for so long? Honestly, it was struggling to get 16-17. Now, it is back up to the normal 20-22mpg we're used to getting. I suppose the only other notable variable that would have an effect is that the weather is a bit warmer now (even though we never seemed to notice a decrease at all last winter) - and we're only talking 20 degrees or so.
But to go from 16.5mpg to 21mpg (average) over a couple thousand miles is definitely interesting - that's a difference of 4.5mpg, or a 27% increase, which is quite a bit IMHO. The driving route over these miles did not change significantly (nor the road conditions). Something obviously changed considerably...
-Ryan |
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| amikhail |
This is what happens, IMHO:
When you reset trip computer, it continuously calculates mpg. Data coming next second is adding up for average calculation since last reset. So the longer you drive - the more accurate numbers you will get.
Try reseting your trip computer on an empty highway at low rpm cruising. Your mpg would skyrocket right away and will gradually come down to whatever it. On contrary, if you reset it at stop, and start driving in stop and go city traffic, it will be really low and start slowly going up. The longer you stay in stop-and-go, the longer it will take it to come up. Before the reset, you probably had couple of highway trips, which boosted your trip computer mpg.
And on another note - if your car was in service for one months, check the tire pressure! May be you lost some or service deflate the tires to the spec, or just the cold weather. This may affect your mpg significantly.
Just my .02 |
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| ryandinan |
amikhail -
Sorry, maybe I wasn't clear enough in my description of what we've been experiencing -
I realize that the trip computer will average mpg with the miles driven; i.e., if you reset the computer while coasting down a hill, it will show an unrealistic "average" (99mpg sometimes) for a while, until you start accelerating back up the other side of the hill - then it drastically starts coming back down into reality. The more miles you drive, the more stable this average becomes.
What we were noticing, was an average of 16mpg over several tanks of gas (hundreds of miles). Now we are averaging 20-22mpg consistently (again, over several tanks of gas). This makes me think that the MDX goes through some sort of "learning" process after power has been lost for a considerable amount of time; hence the lower gas mileage for that period of time following the repair shop visit. Now that it's "learned" our driving habits, maybe it's "tweaked" something in the computer, and mileage is back up? Who knows?
-Ryan |
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