Difference in Observed and Actual fuel consumption.

[aandu]

From the time I bought the HCH1, I have been noticing this huge disparity between the mpg shown on the console and the actual mpg calculated at fill up.

The worst was on a 250 mile trip last month. The FCD showed a whopping 65 mpg over 250 miles. And at Fillup I got about 48.5.

Last tank mostly was in city. I reset the trip meter everyday, the objective being to achieve 42 mpg daily. I got 42+ mpg every single day. And after I installed the IMA C&C, the last 20 miles (before fillup) gave me an average of about 56+. However at fillup the mpg was 38.5.

Again this week 140 out of a total 180 miles was on highway. Highway mpg on FCD was 64+ (140 miles). The city mpg was 40+ (40 miles). As per the FCD average is 58.67. On fillup it was 53.

The car has been recently serviced with new air, oil, oil filters.

Am I am missing?

Do any of you get the mpg seen on the FCD?

[retepsnikrep]

How exactly are you filing and calculating the mpg?

My method would be

1) Fill car until two clicks of pump.
2) Reset trip meter.
3) Drive till empty
4) Fill car and note amount reqd to fill it.
5) Note trip meter miles travelled and then do calculations.
6) See if they match FCD.

You may need to repeat a few times to get consistent results.
Remember the evap purge system can effect how much you can squeeze into the car.
Best to fill up until second click on pump and not until it's comming out of the filler!

[Aqua]

Is the tires the original replacements? Check the Manuel for the stock tire size.
As this is a large differences. I got the stock tire it's is the 185/70sr14 Bridgestone b381 it's a rr rated tire. It's tire Diameter is 24.2. Check your stock diameter hight as even a diffrent brand is a few points differences/ wider tires are a huge differences.check yours.i
Untitled Document

check if stock tires are RR rated (it's is low resistance rolling special tires) if not get one the same hight as stock if you want better than stock mpg , and even better you need to inflated that tire to 50 psi (longer coasting distance /mine 53 psi heavy load) and hold the steering wheel with two hands in case)
Your calculated mpg seems right, for a stock setup and still learning.
All Regular City driving is 38-40 mpg. depends, on how many traffic light they are, and if your not driving for better mpg. It's all the car was design for 45 mpg.
To work on that you will have to learn to drive looking ahead anticipation action way ahead saving "trottle on or off" in dash com and it's break down your trip to miles or foot travel, and what it's consider coasting or "throttle off"
As this is the bottom line that the math does.
Next higher is reducing wind resistance. Mod to do.
Use the MIMA as I describe to better your city mpg.
And you could get better freeway mpg helping too.. If you can't fix the mpg Gage just keep track of gas spend in a month now record and after driving correctly it's takes a big driving effort see earier post. and with air mods you should make it go down a bit Good luck.

[Aqua]

Looking way ahead also let's you know what lane construction on and take the far lane before you can't . Here about timing the stop light it's devided in sections. Middle post
SignalGuru my next favorite thing

[aandu]

Originally Posted by retepsnikrep

How exactly are you filing and calculating the mpg?

My method would be

1) Fill car until two clicks of pump.
2) Reset trip meter.
3) Drive till empty
4) Fill car and note amount reqd to fill it.
5) Note trip meter miles travelled and then do calculations.
6) See if they match FCD.

You may need to repeat a few times to get consistent results.
Remember the evap purge system can effect how much you can squeeze into the car.
Best to fill up until second click on pump and not until it's comming out of the filler!

My routine is pretty close to what you have mentioned. The only difference is I am now filling up every 300 or so miles.

The 300 mile mark is out of habit. All cars I have had so far used to give me about 300 miles per tank (Alto -330, Ignis LPG -320, Arosa TDi-360,etc).

[aandu]

Originally Posted by Aqua

Is the tires the original replacements? Check the Manuel for the stock tire size.
As this is a large differences. I got the stock tire it's is the 185/70sr14 Bridgestone b381 it's a rr rated tire. It's tire Diameter is 24.2. Check your stock diameter hight as even a diffrent brand is a few points differences/ wider tires are a huge differences.check yours.i
Untitled Document

check if stock tires are RR rated (it's is low resistance rolling special tires) if not get one the same hight as stock if you want better than stock mpg , and even better you need to inflated that tire to 50 psi (longer coasting distance /mine 53 psi heavy load) and hold the steering wheel with two hands in case)
Your calculated mpg seems right, for a stock setup and still learning.
All Regular City driving is 38-40 mpg. depends, on how many traffic light they are, and if your not driving for better mpg. It's all the car was design for 45 mpg.
To work on that you will have to learn to drive looking ahead anticipation action way ahead saving "trottle on or off" in dash com and it's break down your trip to miles or foot travel, and what it's consider coasting or "throttle off"
As this is the bottom line that the math does.
Next higher is reducing wind resistance. Mod to do.
Use the MIMA as I describe to better your city mpg.
And you could get better freeway mpg helping too.. If you can't fix the mpg Gage just keep track of gas spend in a month now record and after driving correctly it's takes a big driving effort see earier post. and with air mods you should make it go down a bit Good luck.

I was informed inflating to a high PSI would place more stress on the suspensions, steering, wheel bearings etc. Not sure how true this is. This car is so comfortable in comparison to all other cars I have owned. But it makes the ride comparatively harsh when inflated above 35 PSI.

Let me note all the tyre info I can and update.

[aandu]

Is there a MPG thread for HCH1 ?

[Aqua]

Everything is a trade off a level has been. you can't reach top mpg without less tire resistance, higher air pressure that the second best thing after getting RR- rated tires.
road supenstion is strong, the worse thing you can do to your CV. rubber boot is after a drive is to leave it parked with the steering wheel turned fully. Its will cool down in this new shape and crack turning the other way in time.
All good low profile tires and rims run 50lb air.
Slowly Add air and check when the ride it's get too harsh, and back down a bit, performance is about fine tuning.
And you should always use 2 hands on the wheel.
Think this is your tire.
Tire Size for 2004 Honda Civic
Check now What have you got on the car.
Were talking distance miles it adds up.
TIre Height Chart