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Discussion Starter #1
I am trying to use standard routine to accurately check gas mileage (so far seems to be pretty poor in town--trip computer says 12.3 my calculations seem to be about 14). I have noted that from the first shutoff by the pump, I can continue to click the nozzle many times (about .1 gal each time) and get at least 1.4 gallons in. I know there are instructions that say don't "top off", but I have never seen any backflow or overflow. Anybody else note that quite a bit can be put in after the first nozzle shutoff?
 

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norcalchuck said:
I am trying to use standard routine to accurately check gas mileage (so far seems to be pretty poor in town--trip computer says 12.3 my calculations seem to be about 14). I have noted that from the first shutoff by the pump, I can continue to click the nozzle many times (about .1 gal each time) and get at least 1.4 gallons in. I know there are instructions that say don't "top off", but I have never seen any backflow or overflow. Anybody else note that quite a bit can be put in after the first nozzle shutoff?
Haven't noticed that, I usually round off to the next .25 cents and quit. Will give it a try next time.
 

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Re: Re: Topping off gas tank/Mileage check

hammermdx said:
Haven't noticed that, I usually round off to the next .25 cents and quit...
I do the same! :4:
 

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It would seem letting it 'click off' or rounding to the next .25 each time would provide the most consistent results without any concern at what point it will overflow.
There is more to 'stuffing' the tank than what comes back to you out of the filler pipe. There is a greater chance of leaking raw fuel to the vapor cannister which in time will render it ineffective.
 

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DaleB said:
It would seem letting it 'click off' or rounding to the next .25 each time would provide the most consistent results without any concern at what point it will overflow.
There is more to 'stuffing' the tank than what comes back to you out of the filler pipe. There is a greater chance of leaking raw fuel to the vapor cannister which in time will render it ineffective.
This thread is of interest, because I am the King of overfilling till it sometimes splashes out. What is a 'vapor canister'? And what does it do?
 

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OP MDX said:


This thread is of interest, because I am the King of overfilling till it sometimes splashes out. What is a 'vapor canister'? And what does it do?
It absorbs fuel vapors to reduce pollution in accordance with EPA regulation. It will become ineffective over time if regularly saturated with raw fuel. Resulting in more gas odors as well as failing emissions test, requiring replacement.
Topping off to me can result in more waste (at over 2 bucks a gallon) and makes as much scense as not filling the tank until the indicator is reading right on empty every time.
I think the disadvantages far outweigh any advantages (which I am still trying to find...).
 

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Instead of farting around topping off why not just accept the fact that you will have to hit a gas station 15 miles earlier.:8:
 

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Discussion Starter #10
DaleB said:
As indicated in the initial post, the goal was finding some benchmark manner to fill the tank for accurate mileage checks--not to increase cruising distance. In light of the interesting comments re possible negative results from topping off, perhaps then the best way is to just stop on the first shut off at the pump. However, that presupposes that all pump systems will shut off at the assume level. I wonder if they do. E.g, will that equal the same tank level in each instance. If so, that of course would be the way to do it.
 

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There a bound to be variation as a result of temperature, the tolerances of the shutoff device, etc.
Perhaps using the same pump every time, during the same time of day, etc. will help that situation. I suppose this is why we check for average mpg, because it's not an absolute.
The more refills, the closer the numbers gain some validity, whether you top off, or wait for the pump to click-off. You would need to do it the same way every time to add more validity to your results.
So clicking off is no less or more accurate than topping off, but certainly less troublesome IMHO.
 

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Discussion Starter #12
DaleB said:
There a bound to be variation as a result of temperature, the tolerances of the shutoff device, etc.
Perhaps using the same pump every time, during the same time of day, etc. will help that situation. I suppose this is why we check for average mpg, because it's not an absolute.
The more refills, the closer the numbers gain some validity, whether you top off, or wait for the pump to click-off. You would need to do it the same way every time to add more validity to your results.
So clicking off is no less or more accurate than topping off, but certainly less troublesome IMHO.
 

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Discussion Starter #13
DaleB said:
There a bound to be variation as a result of temperature, the tolerances of the shutoff device, etc.
Perhaps using the same pump every time, during the same time of day, etc. will help that situation. I suppose this is why we check for average mpg, because it's not an absolute.
The more refills, the closer the numbers gain some validity, whether you top off, or wait for the pump to click-off. You would need to do it the same way every time to add more validity to your results.
So clicking off is no less or more accurate than topping off, but certainly less troublesome IMHO.
Good point. So, In likelihood, from a statistical standpoint, with many fills at many pumps using the "first shutoff" approach, seems the number of gallons in the tank would regress to the mean thereby making individual variances insignificant. Hmm--maybe a good engineering paper.
 

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Dear norcalchuck:

You may remember me - I asked the question on how to adjust the fog lights and you kindly supplied picture references.

Now I am having a problem with my outside temperature gauge.

I have started a thread.

A poster has indicated where the sensor is.

Perhaps you have a diagram on the exact position? If so, could you post it either here or in my thread:



Outside Temperature gauge.

Many thanks.

JeffK
 

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Discussion Starter #15
JeffK said:
Dear norcalchuck:

You may remember me - I asked the question on how to adjust the fog lights and you kindly supplied picture references.

Now I am having a problem with my outside temperature gauge.

I have started a thread.

A poster has indicated where the sensor is.

Perhaps you have a diagram on the exact position? If so, could you post it either here or in my thread:



Outside Temperature gauge.

Many thanks.

JeffK
Here is the diagram.
 

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norcalchuck said:
... I know there are instructions that say don't "top off", but I have never seen any backflow or overflow. Anybody else note that quite a bit can be put in after the first nozzle shutoff?
Prior to buying the MDX, I used to top off all my cars. Within the first 2.5 months of owning the MDX, overflow problem happened to me on 2 separate occasions. In both cases, I tried to top off the tank (like I have always done on all of my other cars) after the flow shut off automatically.

I since changed my habits with the MDX, and never top it off. :headshake

Some additional related information on this can be found in this previous discussion thread:

http://www.acuramdx.org/forums/showthread.php?s=&threadid=2154&perpage=15&highlight=overflow&pagenumber=1
 
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