2000 Insight MPG dropped after new battery and IMA

[earthguywill]

Newbie to this sight, but driving my Insight since summer of 2000. I had much better power and MPG prior to a warantee replacement of my battery pack and IMA controller (was getting combined mileage of around 63-64 MPG, now down to 54 MPG and power seems less than before). I've been driving the same freeway miles since owning the car (HWY 280 in the SF Bay Area), and travel 52 miles each way from home in Pacifica to work in San Jose. Average speed is around 60 mph, and driving habits are even more subdued since the mileage dropped... dealer can't find anything wrong, but I know my car has done much better prior to the new battery/IMA replacement. Tire pressure is 45psi and I'm using every trick in the book but struggle to get 60 MPG on the highway. I've read the FE tips and practice many of them already. Any suggestions or other advice? Thanks in advance!

[xcel]

Hi Earthguywill:

___No swap of tires recently, was there? How about jacking up a wheel at a time and giving them a spin to make sure a brake is not grabbing? How about alignment? Any slight movement to one side if you were to let go of the wheel? Are you seeing 19 of 20 bars and when you do, IMA should be out of the picture out on the highway. Is lean-burn allowing 80 – 90 + on the iFCD at those speeds and with the SoC that high?

___Good Luck

___Wayne

[Right Lane Cruiser]

Hi, EarthguyWill! What is the state of charge (SOC) shown? It is possible that you are being subjected to a background charge. Other people here are more knowledgeable about this sort of thing than I, but possibly your vehicle needs to go through a "recal" event to help the electronics recalibrate its understanding of your new battery's charge state.

In order to force one of these you would need to disconnect the 12V battery for around 2 minutes or so. Once the battery is reconnected when you start the car the SOC should go to zero bars of charge. Take the car out for a bit and drive it -- you'll get a forced charge event until the battery is showing full charge. At that point the computer will have learned the correct state of charge of the pack and will be able to correctly report it via the dash gauge.

I know that a couple of months back I had to do something similar for one of the other member's HCHI because it wasn't behaving correctly -- after the recalibration everything has been acting as it should.

Since the process is straightforward and pretty painless, possibly it would be worth your effort to just try?

With that, a belated welcome to CleanMPG! We are glad to have you and hope that you will stay and continue to post. You have one of the most advanced automobiles on the road and you've found a place full of experts on your vehicle and also on fuel efficient driving.

Good luck and let us know your progress!

[Right Lane Cruiser]

Ha -- Wayne beat me to it!

He's one of the experts I was talking about. Check out his signature!!

[shifty35]

Dealers have a tendency to over-tighten the rear brakes, causing them to drag slightly. If you've never had a recal (sudden loss of battery charge leading to forced charge), then you might have just taken a hit from the forced charge. My current driving style involves a lot of FAS and coasting, so it takes me a good 3-4 days to recover from a recal due to diminished charge opportunities.

How long has it been like this? Just a couple days or a tank or more?

[msirach]

Be prepared for a couple thousand miles to relearn your car. When mine was changed, the first tank or two was great then it seemed to degrade. I did a few resets and got used to the new "powerband." The assist assisted much easier but it made your background charge impact the mileage much more. Concentrate on NOT using your assist. It's tough, but after you figure it out, mpg will improve. I have raised my lifetime mpg from 62.5 (137,000 miles)to 64.1 (161,000 miles).

[Blake]

when was the battery pack replaced? It might be possible that the effects of cold weather are affecting your ablility to get in and stay in lean burn mode.... that is if its a manual transmission insight.

Wayne and shifty both bring up good points. I will also submit that even though your charge/assist gauge might not be showing anything, that gauge is more of a guess. I have MIMA installed and I can tell you that more times than not, that gauge is off. Many times you'll have a signifigant background charge going on and the charge gauge will not register anything.

Maybe try a forced recall to see if that fixes the issue. Also, check some of the easy things that are often overlooked. 12 volt battery charge (is it going bad?) also check your ground cables in the engine compartment.

Try getting on the highway and driving 55 mph and letting almost completely off the gas and slowly getting back on it. Does it go into lean burn mode?

[earthguywill]

Thanks for all the great replies. The battery was replace a year ago, but the power problems and mileage issues have been plaguing me since the first IMA was replaced on a factory recall over three years ago, and I have not noticed an appreciable change in varying weather conditions since the IMA replacement.

I have been experiencing the recal event (sudden loss of charge), but wasn't sure why it was happening -- it has been a fairly regular (at least once a week) and drives me nuts. My SoC is rarely full and the discharge seems disproportionately fast in relatively tame driving conditions. Recharging the batteries (when possible) takes much longer than it used to... I have two stretches of over a mile downhill on my commute to work and there is little to no charge increase showing on the gauge (though the charge gauge shows power is being generated)... In the first 4 years I owned the car, I was always able to keep the batteries nearly fully charged, but can only think of one or two times in the last three months where the charge was at 19 bars. The charge depletion is very rapid for the assist power actually provided.

The 12 volt battery was replaced 10 months ago and seems to be fine at this point. I am able to get 80-90+ on some stretches of the freeway, but I rarely achieve a full SoC these days.

I will try a forced recal to see if that helps. Can someone explain more about the background charge?

[Right Lane Cruiser]

A background charge is one that is not shown on the built in charge/assist meter. Since it is stealing some of your power it will show up as lower instantaneous MPG numbers. The charging rate is less than a "forced regen" so it won't suck your numbers down as low, but there is still an impact.

If I recall correctly, a forced regen does not occur until you get down to 1/3 charge. Anything over that should be a more gentle charge happening that you won't see directly, but you will see the SOC rise.

Based on your symptoms I would definitely try a forced recal first.

[Blake]

Yep... try a forced recal and do your best to not use any assist until the SoC gauge reads full. This will most likely require a time of day that has little traffic and a road that is decently flat for some distance.... at least that would be the easiest way of getting charge back into the pack.