| ndahbar |
It's now crystal clear to me why the MDX has much lower mileage in city driving than on the highway. RPM. I don't know if it's a combination of the gearing, the engine computer, the drive-by-wire throttle, etc., but it's clear that when you drive this car even at part throttle (actually, even a light foot, period) in 1st, 2nd and 3rd gears the engine just revs above 4000 RPM *ALL THE TIME* very easily and effortlessly. In fact I have to pay attention to keep the revs below 5000 or 4500 rpm and I'm NOT flooring it.
Well there you go. Yes the car isn't light, and it's not a tiny engine size, but the RPM is what does it. Alas in the end I don't mind, cuz the torque band is extremely flat and the car just MOVES real well for its weight I must say.
While I am still at about 3300 miles, I am rather confident I can tell that my ECU is in "break-in" mode, especially in 1st gear, the motor just doesn't put out the acceleration like in the other gears. Hard to describe...but it just "feels" like it's being affected by electronics.
I am sure that when the ECU switches to normal mode, I will be able to tell quite dramatically, esp. 1st gear. I think this will occur by 5000 if not 6000 miles for sure. Some have mentioned it's in the 4K-range? Dunno.
Anyhow, there's not much y'all can do about your sub-20 mpg performances in city driving except for driving EXTREMELY conservatively like a senile grandma with very poor eyesight and reflexes. Well I'll tell you guys right now that this ain't, and never will be, my style! Me drive hard. Me say go hug tree somewhere else and not in my backyard. :cool: |
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| MDX350 |
I am at 6K miles, have seen no change in performance whatsoever - so I'm not sure about this "ECU break-in mode".
Also, If you drive normally, rpm's don't go above 4.5K in my X. If you drive gently, never above 4K. Of course, the definition of normal/gentle is subjective.
the X "drinks" gas when idling, and when in 1st gear. So too many stops, and the mileage just zooms down. If you don't stop, even if it goes down to 2nd gear, it's not that bad. |
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| maransm |
I get pretty bad mileage..
City - 18.3
Highway - same... the max I have see was 18.9 when I went for 3000 miles trip. I have put about 10K miles as of now!
Any idea why I am not getting better milage on highways? I live in Colorado. does it make any differenace? Again, I drove to East Coast from Colorado during that 3000 miles trip. So its not the colorado's elevation.
Thanks.. |
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| msu79gt82 |
quote:
Originally posted by maransm
I get pretty bad mileage..
City - 18.3
Highway - same... the max I have see was 18.9 when I went for 3000 miles trip. I have put about 10K miles as of now!
Any idea why I am not getting better milage on highways? I live in Colorado. does it make any differenace? Again, I drove to East Coast from Colorado during that 3000 miles trip. So its not the colorado's elevation.
18.3 for PURE city driving is fantastic; probably the best I've ever heard of. Even if the 18.3 is for mixed city (some country) that is very respectable. Not sure why the highway is not better - it should be.
As I've posted elsewhere we just returned from a 9-day 2500+ mile tour through the Great Smoky Mountains National Park (East Tennessee); ~2500 miles of vacation driving, with many of it in the mountains and average mileage for the trip was 21. Worst tank mileage was 19.6 with over half of that tank mountain driving (cool day so no A/C) and the best tank mileage was 22.4.
We kept the cruise control set to about 77ish on the highways. Do you drive well above 80? Do you accelerate hard and pass a lot of people on the freeways? 18.9 max on pure interstate driving does seem low. |
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| hockeyplayer |
| MARANSM......What do you think the gas mileage should be...???? 18.3 average is pretty decent considering you are driving a "bus". |
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| DevExpert |
I do not beleive it. There is NO way you get 18.3 city. Maybe rolling down the hill all the time :2:
quote:
Originally posted by maransm
City - 18.3
Highway - same... the max I have see was 18.9 when I went for 3000 miles trip. I have put about 10K miles as of now!
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| DaleB |
| I would not care much about getting 22 or 23 on the highway if I could average in the 18's all the time. |
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| frostyra |
quote:
Originally posted by maransm
I get pretty bad mileage..
City - 18.3
Highway - same... the max I have see was 18.9 when I went for 3000 miles trip.
Just out of curiosity, do you reset your trip computer every time you gas up? That's the only way you can get an accurate picture of your mpg. Doing that reset, I get 15-18 going to and from work (lots of start-stop), and 22-26 on pure highway driving.
If you don't reset the computer, you're just reading an average since "day 1", and it would be almost impossible to change that by much after thousands of miles. |
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| norcalchuck |
quote:
Originally posted by MDX350
I am at 6K miles, have seen no change in performance whatsoever - so I'm not sure about this "ECU break-in mode".
My dealer service department denies that there is any such thing as a "break-in mode" that magically resets itself at some predetermined mileage. Does anyone have a factual basis for what appears to be an MDX "urban myth"??? I'd be interested in seeing that proof. I did not see anything in the maintenance manual and my dealer says it's bunk. |
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| JeffK |
I agree: I have never heard of a "break in mode".
In my previous posts, I have also complained about the mileage of my MDX.
It is no better than my 2001 Blazer, about the same weight and similar displacement. The Chevy engine is ancient while the MDX is "state of the art".
To recapitulate:
75 mph and above: About 18/19 mpg
65 to 75: about 21 mpg
60 to 65: about 23 mpg
55 to 60: about 24 mpg
City driving, about 14 to 16 mpg.
However, I use regular and save abut $.20 per gallon over premium.
The mileage with premium was no better and no worse than with regular - i.e. identical.
There was another post dealing with resetting an emission control.
I am waiting to hear the results. |
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| norcalchuck |
quote:
Originally posted by JeffK
I agree: I have never heard of a "break in mode".
In my previous posts, I have also complained about the mileage of my MDX.
It is no better than my 2001 Blazer, about the same weight and similar displacement. The Chevy engine is ancient while the MDX is "state of the art".
To recapitulate:
75 mph and above: About 18/19 mpg
65 to 75: about 21 mpg
60 to 65: about 23 mpg
55 to 60: about 24 mpg
City driving, about 14 to 16 mpg.
However, I use regular and save abut $.20 per gallon over premium.
The mileage with premium was no better and no worse than with regular - i.e. identical.
There was another post dealing with resetting an emission control.
I am waiting to hear the results.
My numbers are a tad better on the interstate flats. Clearly, the A/C compressor is good for about a 1 mpg hit in high temps.
My city mileage without A/C was about 13.4. With A/C it's consistently about 12.4. My driving pattern however, except for occasional trips, is only about 100 miles per week. All short trips, all stop and go heavy city traffic and up and down hills part of the way. And this is with watching the trip computer and a light foot.
The bottom line is that it takes a certain amount of energy to move a certain mass. The MDX is a heavy car. they have done a great job keeping wind drag down, and with gearing and other engine controls, hence, the great highway mileage for its weight class. But a hug amount of kinetic energy is wasted in stop and go driving, and driving up and down hills. As an aside, adding rack, sidesteps, full size spare and other accessories probably means I am toting around about 200 lbs more than the published base weight, which can also cause a hit on mileage. |
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| xcel |
Hi All:
___My wife gets 17 to 18 in stop light to stop light style city driving and I can squeeze maybe another 1 mpg above that over the same route. When she first got the X, she was lucky to get 16 mpg. The instantaneous graph is all that needs to be watched in our case to get the X back above 17 mpg. She dislikes the instantaneous graph because it makes her accelerate a bit more conservatively than she normally would but I don’t think that is a bad thing. The X does seem to be a bit more miserly now that it has > 5000 miles but I didn’t see an incredible jump like I have seen on the 03 Corolla once it surpassed 25,000 miles. It went from mid to high 30’s on the hwy to almost the mid 40’s so I figure something must have changed with the ECU for this kind of increase?
___Back to the X’s 3rd, 4th, and 5th gear RPM discussion. I don’t believe it. I have never had the X over 3000 RPM’s and I try very hard to keep her under 2500 while taking off from a stand still. With that being said, I can usually get the Instantaneous into the 15 to 17.5 mpg range by the time the tranny hits 3rd gear. You may not want to be behind me at a light given my timidity during acceleration but in the case of mileage, I believe you can squeeze what you want out of the X (within reason) because you have the information in front of you to do so.
___On the highway side of things, we were on I94 this evening and for over 10 miles and I had that instantaneous up in the 35 – 40 mpg range at 55 to 70 mph! We didn’t need the A/C since it has been unusually cool in the Northern burbs the last two day so that helped along with some minor drafting given the congestion we were in but I was truly amazed! With the 25 + miles, I picked up a whole 1 mpg from 17.6 to 18.6 with over 175 miles on the X at the beginning of the drive. This included stop and go driving for over 2 miles where the Hwy became a parking lot and city type driving on the way home given BestBuy, BlockBuster, and Ben and Jerry’s needed a visit ;)
___Personally, I think I could squeeze 30 + mpg out of the X on the hwy with a little help from a low slung 18 + wheeler to draft behind from lets say 10 + car lengths possibly? All of the above is while using 87 Regular Unleaded like I always have … On a negative note, I dislike the Grade Logic control sometimes. It will sit in 4th even while cruising at 45 + mph on level ground for what seems to be an inordinate amount of time. To kick it up, I drop off the accelerator for an instant until it engages 5th and than apply the accelerator slowly to increase speed. This happens rarely but when it does, it ticks me off.
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net |
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| ndahbar |
| Well, on www.vtec.net there were some posts by this guy who works for Honda in Canada, and while they undergo training they teach them about the break-in vs normal modes of the ECU in pretty much all VTEC engines. MDX included we presume. He mentioned that the mileage of the "switchover" is variable between Honda models. So it's between 4K and 6K for all of them, pretty much. |
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| xcel |
Hi Ndahbar:quote:
Anyhow, there's not much y'all can do about your sub-20 mpg performances in city driving except for driving EXTREMELY conservatively like a senile grandma with very poor eyesight and reflexes. Well I'll tell you guys right now that this ain't, and never will be, my style! Me drive hard. Me say go hug tree somewhere else and not in my backyard.
___I guess you can start calling me a senile old tree hugging grandma w/ poor eyesight and reflexes … than again, I can run a decent 100 meter … for being a grandma that is ;)
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net |
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| maransm |
quote:
Originally posted by frostyra
Just out of curiosity, do you reset your trip computer every time you gas up? That's the only way you can get an accurate picture of your mpg. Doing that reset, I get 15-18 going to and from work (lots of start-stop), and 22-26 on pure highway driving.
If you don't reset the computer, you're just reading an average since "day 1", and it would be almost impossible to change that by much after thousands of miles.
Imm.. I havent thought about this. I have never reset the trip computer since the day 1.
Btw, I use 89 grade gas.
Let me start resetting as and when I fill gas and see the change. Will post the results soon.
Thanks for the information! |
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| ndahbar |
quote:
Originally posted by xcel
Hi Ndahbar:___I guess you can start calling me a senile old tree hugging grandma w/ poor eyesight and reflexes … than again, I can run a decent 100 meter … for being a grandma that is ;)
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
:2: :7: |
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| Blueflame |
| Try driving in San Francisco, you will be lucky if you get 15mpg. |
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| elli |
| My best tank is about 15 mpg. The average is about 12-13 mpg. The worst one is 9.5 mpg. If pure city drive in NYC, I think it's about 8.5-9 mpg. Does any one what is the definition of EPA's city milage? I would like to know what kind of city drive that you are able to get 17 mpg? |
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| norcalchuck |
quote:
Originally posted by elli
My best tank is about 15 mpg. The average is about 12-13 mpg. The worst one is 9.5 mpg. If pure city drive in NYC, I think it's about 8.5-9 mpg. Does any one what is the definition of EPA's city milage? I would like to know what kind of city drive that you are able to get 17 mpg?
Stop and go is brutal on mileage. Best I can do with the A/C on in stop/go is about 12.2.
Re your questions, see:
http://www.fueleconomy.gov/
The test used to determine the city fuel economy estimate simulates an 11-mile, stop-and-go trip with an average speed of 20 miles per hour (mph). The trip takes 31 minutes and has 23 stops. About 18 percent of the time is spent idling, as in waiting at traffic lights or in rush hour traffic. The maximum speed is 56 mph. The engine is initially started after being parked overnight. Vehicles are tested at 68 F to 86 F ambient temperature.
http://www.fueleconomy.gov/feg/info.shtml
They then deduct 10%
"To make the numbers in the Fuel Economy Guide more useful for consumers, EPA adjusts these laboratory test results to account for the difference between controlled laboratory conditions and actual driving on the road. The laboratory fuel economy results are adjusted downward to arrive at the estimates in the Fuel Economy Guide and on the labels seen on new cars, light trucks, and vans. The city estimate is lowered by 10% and the highway estimate by 22% from the laboratory test results. Experience has proven that these adjustments make the mileage estimates in the Fuel Economy Guide correspond more closely to the actual fuel economy realized by the average driver."
As you can see, their idea of "city" and most people's actual "city" driving are apples and oranges. |
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| ndahbar |
Yeah, I can attest to these figures being thrown about. 13 mpg for example, is totally normal for me to get in non-highway cruises. Jeez! Well then again, I dunno if I trust the on-board computer too much.
Well...I guess I should pay attention next time to the number of miles I cover between fillups. I know I always burn like 18 gallons (I fill up when real close to empty so like 1 gallon left). I usually drive with A/C on as well though. I wonder if the on-board takes that into account? Does anyone know for sure?
Ah who cares guys, the car only weighs 4500 lbs, far less than many of the SUVs out there, and it's only a 6 cylinder. Whatever it is...tons of others are getting it FAR worse than us. :p
Jeez...I remember when I had a 4.4 X5 2 summers ago....25 gallon tank...gobbled up in NO TIME. I KNOW I was getting like 11mpg in that thing. AT BEST in the city. Good thing I don't drive an ESCALADE. :eek: |
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| Lance Crowley |
Just did a hiway trip where I went right from the gas station unto the hiway and drove 170 miles and then pulled in and filled up. Used mid-grade gas and my speed was a constant 72 mph. Had two stops lights along the way, the drive was between the Twin Cities and Rochester, MN on hiway 52 was is gentle rolling terrain. The trany dropped back to 4th 3X on the trip. Mileage 22.8. Around town I get between 12.5 and 15.5 using mid-grade gas. What I've found is that if you get into the VTEC on acceleration you dramatically cut the mileage. If you listen closely you can hear a change in pitch of the engine when the VTEC kicks in.
While the mileage could always be better, much of it has to do with your right foot and the fact that you're moving a pretty heavy machine around. I don't really expect great mileage when I'm driving around town, stopping at lights, constantly changing speeds and have got the A/C running at full blast. My Jeep G/C V8 was down into the 10 - 11 mpg range under the same conditions and the best it ever got on the hiway was just over 18.
The other thing to remember is that an SUV has about the same aerodynamics going through the air as a brick. |
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| ndahbar |
| The simple truth is, for an "SUV" the MDX engine is revving higher than pretty much every other competitor that I can remember. This is hugely reponsible for low mpg in city driving. Like I said in my first post, RPM is at 4000 RPM at almost EVERY darn shift (or above) without me even pressing anywhere near 1/2-way down on the gas. 'Nuf said. |
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| mogur |
There is no such mode on the MDX (a very few cars do have such a mode) and even if there was, it would not be more than 1,000 miles or so.
quote:
Originally posted by ndahbar
While I am still at about 3300 miles, I am rather confident I can tell that my ECU is in "break-in" mode, especially in 1st gear, the motor just doesn't put out the acceleration like in the other gears. Hard to describe...but it just "feels" like it's being affected by electronics.
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