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CavemanCharlie

Storden,MN

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Posted: 01/16/22 09:00am Link  |  Quote  |  Print  |  Notify Moderator

When I was a lot younger I had a car that I loved and had rebuilt myslef. I always kept track on the mileage at every fill up. If it suddenly went down I knew that I had a problem somewhere and needed to check it out. Of course this was back in the days of carburetors. These days, I'm old and I just read whatever the dash display tells me and figure it's close enough for me.

I understand why people driving RV's across the country might want keep a close eye on it. If I was living that lifestyle I think I would probably write it down by hand too.

Matt_Colie

Southeast Michigan

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Posted: 01/16/22 09:27am Link  |  Quote  |  Print  |  Notify Moderator

Matt wrote:

Most fuel gauges are nearly useless even the ones that I carefully calibrated, the tank shapes just make it that way.

Grit dog wrote:

Interesting statement….
Maybe applies to antique vehicles?

Grit, I am guessing that you mean as opposed to the modern systems that tell you "Miles to Empty"?
toedtoes wrote:

Years ago, I took my young nieces "up the hill" to the snow. We had a great day. When it was time to go home, the computer read that I had about 20 miles til empty. I made a big deal about that to the girls and then said "oh, let's take a risk" and started down the hill without filling up. Over the next 60 miles, every time we'd pass a gas station they'd beg me to stop and fill up. I wouldn't. After we had gotten all the way down, I finally stopped and they practically cheered in relief.

Well Grit, the practical matter is that the body computer reads the fuel level off the same old "float and resistor" sender that has been in use since cars started having electrical systems. It uses that to record a fill up (if less that a fill, it fakes it), then it uses the injector pulse width to total up the fuel used. If every thing is good, this can be pretty close. (I did own a VW that had a mechanical gauge, and I got the reserve valve from an older model because I still couldn't trust it.) So, if you live out side of New Jersey and can fill your own tank, you can create some repeatability there, but the instruments are still problematic. If you could see the efforts that have been put into both road vehicle and aircraft fuel quantity measurements, you would be surprised by the range of technology uses in these efforts and the total lack of success.
I always fall back on the line in a FAA manual that says that the only time you should believe what a fuel gauge says is when it says "Empty".

Matt- a refugee from the labs of Detroit


Matt & Mary Colie
A sailor, his bride and their black dog (one is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.


Matt_Colie

Southeast Michigan

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Posted: 01/16/22 09:33am Link  |  Quote  |  Print  |  Notify Moderator

Matt wrote:

Most fuel gauges are nearly useless even the ones that I carefully calibrated, the tank shapes just make it that way.

Grit dog wrote:

Interesting statement….
Maybe applies to antique vehicles?

Grit, I am guessing that you mean as opposed to the modern systems that tell you "Miles to Empty"?
toedtoes wrote:

Years ago, I took my young nieces "up the hill" to the snow. We had a great day. When it was time to go home, the computer read that I had about 20 miles til empty. I made a big deal about that to the girls and then said "oh, let's take a risk" and started down the hill without filling up. Over the next 60 miles, every time we'd pass a gas station they'd beg me to stop and fill up. I wouldn't. After we had gotten all the way down, I finally stopped and they practically cheered in relief.

Well Grit, the practical matter is that the body computer reads the fuel level off the same old "float and resistor" sender that has been in use since cars started having electrical systems. It uses that to record a fill up (if less that a fill, it fakes it), then it uses the injector pulse width to total up the fuel used. If every thing is good, this can be pretty close. (I did own a VW that had a mechanical gauge, and I got the reserve valve from an older model because I still couldn't trust it.) So, if you live out side of New Jersey and can fill your own tank, you can create some repeatability there, but the instruments are still problematic. If you could see the efforts that have been put into both road vehicle and aircraft fuel quantity measurements, you would be surprised by the range of technology uses in these efforts and the total lack of success.
I always fall back on the line in a FAA manual that says that the only time you should believe what a fuel gauge says is when it says "Empty".

Matt- a refugee from the labs of Detroit

ajriding

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Posted: 01/16/22 10:02am Link  |  Quote  |  Print  |  Notify Moderator

If you have to ask Im not gonna tell ya

Veebyes

Bermuda & Maryland Eastern Shore

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Posted: 01/17/22 07:50am Link  |  Quote  |  Print  |  Notify Moderator

MPG is MPG. Not much can be done about it other than modify some driving habits, maybe. Lighten that right foot, anticipate stops & change them to slowdowns if possible, don't try to keep up with cars coming off lights.

I have a very accurate MPG average over time & miles. I have not reset the computer in over eight years. The truck is only used for RV trips


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opnspaces

San Diego Ca

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Posted: 01/17/22 04:24pm Link  |  Quote  |  Print  |  Notify Moderator

I'm guilty of recording. And being a computer guy I recorded on a spreadsheet that automatically calculated my MPG and such. I would fill up and write the trip meter mileage down on the receipt and then reset the meter. At home I opened the spreadsheet about once a month and entered the date, miles driven, gallons filled and the cost per gallon and if on a trip a note of where I filled. The spreadsheet did the calculations after that.

I remember as a teenager I had a ford ranger that I would track this way. One day the gas gauge just quit. I knew that I could drive 169 miles until empty. Knowing that and being a teenager I drove that truck for years with no working gauge and never ran out of fuel.

Here's a small snippet of my spreadsheet.
[image]


2001 Suburban 4x4. 6.0L, 4.10 3/4 ton
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Brooksbc58

Permian Basin

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Posted: 01/18/22 10:47am Link  |  Quote  |  Print  |  Notify Moderator

I have 2 speedometers, 2 fuel gauges, and 3 odometers in my truck. I'm never quite sure how far I've driven, or how fast I got there.

dedmiston

Coast to Coast

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Posted: 01/18/22 11:26am Link  |  Quote  |  Print  |  Notify Moderator

Segal's Law

Quote:

A man with a watch knows what time it is. A man with two watches is never sure.



2014 RAM 3500 Diesel 4x4 Dually long bed. AISIN trans & 4.10 rear. B&W RVK3600 hitch • 2015 Crossroads Elevation Homestead Toy Hauler ("The Taj Mahauler") • Hooligan #3

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ppine

Northern Nevada

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Posted: 01/18/22 12:51pm Link  |  Quote  |  Print  |  Notify Moderator

Keeping track of mileage has changed my style of driving. Now I am more of a hyper-miler and slow down ahead of time and don't accelerate that hard. Use cruise control when it is safe. That is how I got to 23.8 mpg in a one ton Ford diesel.

dedmiston

Coast to Coast

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Posted: 01/18/22 02:05pm Link  |  Quote  |  Print  |  Notify Moderator

ppine wrote:

Keeping track of mileage has changed my style of driving. Now I am more of a hyper-miler and slow down ahead of time and don't accelerate that hard. Use cruise control when it is safe. That is how I got to 23.8 mpg in a one ton Ford diesel.


Sounds legit.

[image]

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