About a week before I had the control arms replaced, new tires, and oil change, I began noticing that my 07 with 35k miles was getting poor MPG, from 45 down to 39. I've corrected and tested for weather and, like you, I know my roads/route and how to drive the car. Post control/tires/oil I am getting the same results. But I am trying even harder to get better MPG and it's not working. The instant useage bars meter was usually at the 50 mark, and often above under normal driving. But now, it hovers much lower and rarely gets above 50, even on flat roads with no traffic/stops and constant 50mph. That used to net 60+. The car feels sluggish and even sounds like it's working harder.
No lights or warnings, and the car was just at dealer. I will say the car didnt seem sluggish pre-dealer visit.

Any thoughts?

PS - the goodyear fuelmax tires are significantly quieter, and handle much better than OEM.

 

Maybe it is time for a good wheel alignment? Hal

 

What pressure are the tires at? Maybe the dealership installed them at a lower pressure than you are used to?

Any chance they would have applied either of the newish software upgrades (Power Control or CVT control) without mentioning it? I find the CVT control upgrade made my car feel a little more sluggish--kinda like a forced "econ" mode. If I press pretty firmly on the gas, it will run a higher RPM than it used to which sounds similar to your comment about your car working harder.

I can't say if it has had a positive or negative impact on my mileage though--it's been in the toilet since I started my new commute and it's still in the toilet after the upgrade.

The only other things I can think of might be that they over filled the oil (check the dipstick), or that the new tires might not be as fuel efficent.

 

- four corner alignment was performed by my reputable shop vs dealer
- PSI set to 42 all four tires, had been 43/41 prior
- thought the same as you...did dealer perform SW upgrades, but they say no
- oil level is my next check, as is type of oil.

Odd that I cant keep the MPG bars in the range I normally could...makes me think SW upgrade. Any way to check?

 

I put the same tires on maybe a month ago...I raised my PSI to 49/45 to regain my FE. I started with 40/36, then 45/40 - but found 49/45 to be 'just right'.

 

It sure sounds like the car isn't rolling as efficently as before - the engine didn't really change. The drop you've reported seems outside the range of what i'd expect minor tweaks such as synthetic oil or improper air pressure.

I'd have a second look at the alignment (maybe something is loose after the repair which throws the alignment off while driving?). The tires (not the pressue) should remain a suspect too until you can prove otherwise.

Good luck and keep us posted.

-dan

 

A couple factors with potential to lower your mileage:

1. Maybe dealer overfilled oil, or used wrong grade? The first most likely, in my experience.

2. You switched tire brands, right? And are going from well-worn to brand-new, with all that implies. What were your OEM's, assuming this is the first change? Honda tends to pick the OEM with LRR in mind, fwiw. Maybe the Goodyear Assurance is just so-so RR? Nobody in the industry seems to want to nail these things down.

 

I just got my 2007 HCH back from the dealer, and they -did- perform apparently "four software updates".

My mileage has dropped from 47.5 to 33.5. Yes, that much. Assist almost never comes on anymore, even when climbing hills its just 100% ICE. Occasionally assist will come on, but for half a second, and then ramp down.

This is horrible; and knowing dealers, they'll either lie their way out of it or - well, I'm sure they can't put the firmware in the PCM "back" to what it was...

It's almost like the car isn't a hybrid anymore. I too used to be able to usually 'float' the instantaneous MPG meter around the 50mpg mark. Now it usually sits between 20 and 40.

When assist does come on its only when i 'punch it' violently. No more assist up hills, no more assist when accelerating.

So I'm figuring my dealer screwed this up, and probably will never admit to it. I have a case open with Honda but that probably won't matter either.

 

Your IMA assist is not functioning optimally. The poster that talks about the software updates probably is on the right track. I have a 2006 HCH2 and I remind them not to take updates when I get my car serviced. They did it once anyway, wouldn't admit it, and it was a step backward ( car goes into auto-regen much easier than it did upon purchase), but I still get 50 MPG ( last tank was 50.3 by hand calc and 49.3 by the trip odometer and calc display) so I am cool with it. But I wouldn't ever take a software update again for any reason, including the technical service bulletin issue currently being discussed.

 

If these software updates are negative --- then, I know, stupid question; Why are they doing them?