Sometimes when i am going down hill with no assist or regen, the instant mpg gauge goes from maxed out down to zero. Is this because the engine has shut down? why dosen't it just stay maxed out?

troy

 

I've noticed this also on my 06. It does it when the engine is not fully warmed up and going down hill. A little blip on the gas pedel corrects it but it may do it again 20 - 30 seconds later, a second blip corrects again. I know the engine has not shut down because it Hasn't fully warmed up. Why it does this I do not know.

Luckyflyer

 

Just allow it to happen. This is your IMPG computer calibrating itself. It does not affect the odometer readout of per-tank fuel economy, as that is handled separately. You'll notice it's a re-calibration by the systematic way the meter drops to zero, kind of a two steps forward one back thing. After it sachet's down to zero, it will rise back up again in just a couple of seconds. Tapping the pedeal does stop this, but it also stops the calibration.

 

Today we learn something!!
Thanks,
Lucky

 

Has anybody actually found someone from Honda flat out stating this is the case? We know about the battery recal because it's been published. The iMPG meter, though, I haven't seen anything authoritative, and theories abound. I've seen it with hot engines, cold engines, engines coasting at 70mph, and just about any other place you can imagine, but *always* in situations where there is no boost/regen, but it's possible the system has gone "valves sealed." I've even seen it waffle up and down like it can't make up its mind whether to display 100+ or 0. To me, it looks more like a division by zero is occuring somewhere and confusing the thing, but hey, that's just my own theory.

 

I've not seen anything from Honda. I just keep seeing "recalibration", so I go along with it! I agree... it MOSTLY occurs on cold decel, but I have seen it in other situations, too. I have confirmed that it does not negatively impact MPG as recorded by the trip meters. Once, when this condition was occuring, I saw my instant gauge at zero, yet the trip meter gauge was increasing (early in a tank when short stretches have a major impact on the numbers, and on a downhill run).

 

Interesting theory. For as often as my car does it, you'd think I had one of the most "calibrated" cars on the road . I have only noticed it happening when the engine is cold (not necessarily the ambient temp), but we've only had the car since October so maybe I haven't had the chance to see it in other circumstances yet.

If it were "calibrating" then how does it know to increase your average MPG while it's doing it? Based on my over-simplified logic, if it was doing a calibration, your average MPG would stay flat until the calibration was over, but the average definitely climbs each and every time it "calibrates". I'm with you--I think it's some sort of bug. Then again, if that is the worst bug the car has, I will be a happy camper.

 

This happens to me everyday. I leave my house drive about 1-2 miles reach the same stretch of road at about the same time downhill coasting @ 50mph impg slowly goes from 100 down to zero and will sit at zero until i give it gas..... does not affect my overall mpg.... weird. Will discuss it with dealer during A-1 service.