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Discussion Starter #1
I haven't had this vehicle long, so maybe I'm missing something, but the trip computer seems WAY off in almost all respects.

2008 MDX Tech (Canadian)

Flipping through the trip computer when i first got it, I noticed it seemed way off, so I reset everything. I also reset A to be manual, not automatic when filled up. I drove the car for a while and didn't really think much about it. I went back to check the trip computer. My average KMPH was 33. My estimated fuel mileage was around 25L Per 100KMs. Both of those are way off.

So I went and got gas, and reset everything again. I haven't driven it much since then, but looking it now shows my average speed somewhere in the 30KMPH range, and my fuel mileage as about 28L per 100KM. Again, those numbers don't make much sense.

Do these computers go bad some how? How does it calculate these numbers? What can I try as a correction?

Thanks!
 

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For USA:
Those are 9-8 and 7mpgs.

Forget about average speed reading on the ODO because its useless..
What is your elevation? what is your acceleration behaviour (What RPM you shift)? Extra load?
What is the real speed you drive at.

The 2G MDX is a gas guzzler in the city specially in low speeds (Under 60kph).
 

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Discussion Starter #3
Ocean level, no towing. shifting is computer controlled. Slightly heavy foot, slow driving.

Makes me wondering if I should start replacing 02 sensors.

Really, the average speed dosent work? That sucks, seems like a neat metric to have. There must be some way to calibrate it. I have the 07 shop manual, Ill flip through that to see what I can find.
 

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It really depends on when you shift.. You control the shifting in full auto by the amount of pressure you apply to the gas pedal, The further you go the longer it hold the gear... In order to be gas efficient you should avoid shifts above 2000RPM. As for your numbers I have been there, If I drive like a lunatic I can hit 9mpg easily.. In the city I am usually at 12mpg driving carefully and almost 17mpgs if driving super grandpa mode.
 

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My average KMPH was 33.
Disregard that average speed, it has no real meaning.

My estimated fuel mileage was around 25L Per 100KMs.
Immediate A or average B? 25 liters per 100 kms is way too high. You should not be getting that unless you constantly press the pedal to the floor each time you start moving. The immediate A mileage is affected by idle a lot, so if you are idling a lot (heating up when it's cold or cooling when it's hot, for example) that will add the fuel spent, of course, and will drive the L/100km up.

After years of driving I found that both A and B are pretty accurate. The easiest way to confirm is to drive from empty / refull to empty again and compare the gas used per 100kms vs what immediate A is showing.

My average B (so mixed city/highway) is 15L/100 km right now (and it's always been around this mark since I got my 2008 back in 2011, fluctuating to more gas in winter, naturally with all the warm ups and more fuel spent to drive in snow, etc). My immediate A goes as low 9.5-10L/100 km on highway cruising at 110-120 km/h and strictly city driving with short trips and full stops at all stop signs and on red before turning right goes as high 20L/100 kms during worst times.
 

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Discussion Starter #6
Right now they are both the same, as they have been reset at the same time. I have A set to manual reset right now.

I assume you mean "immediate A" just based on A resetting with each fuel up, and B not being reset to give an overall average, or am I missing something?

Thinking about my driving in the last little while, there has been a lot of sitting idle. Next tank Ill have to actually run the numbers manually and see what I get.
 

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I assume you mean "immediate A" just based on A resetting with each fuel up, and B not being reset to give an overall average
Yes.

Thinking about my driving in the last little while, there has been a lot of sitting idle.
I think that's your answer. More idle means less MPG (which is more L/100km).

Yeah, run a normal cycle with normal driving and see what you have.
 
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