My information center (Lie-o-Meter) did something I have never seen before. On the way in to work this morning the thing changed from MPG to gallons left in tank. I was running low on fuel, about 1/8 left, and then the low fuel light came on. I reset it back to MPG,and it didn't go back to gallons left the rest of the ride. I didn't see this mentioned in the owners manual. Has anyone seen this before? I was actually trying to figure my fuel gauge out, since every time it's on E i have 4 1/2-5.0 gals left. I hand checked the computer to my calculations, and it's pretty close. It said 11.5 mpg,and I got 11.2 mph combined city/hwy.

oh by the way I did not make up the term Lie-o-Meter. Someone on this site used it and I thought it was a good name for it.

 

The good news is, considering the source of information, aka Lie-o-meter, is that regardless of whether it is showing you MPG or fuel in the tank, you can be assured the information displayed is incorrect.

 

the LOM in my ex shows the temp correct. and the directional heading is right on too.

 

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Sad but true - so much of the information displayed in these threads is utter nonsence. For example, the term "lie-o-meter". Now, in fairness, it COULD well be that the kids posting their confusion over the fuel indicators simply dont know how to run a REAL gas mileage test, and/or dont know how to do basic fuel mileage match caluclations (which would explain why they think that over-head computer is "lying" to them).

Reviewing my notes, they confirm the postings in here are incorrect, and the mileage indicator is dead accurate.

ALL TEST FIGURES BELOW ARE WITH A BONE STOCK '05 v-10 Ltd. 4wd with 3.73's, towing loads of either 10,100 lbs. or 11,400 lbs. (the extra tow weight between my two trailers dosnt seem to make much difference).

All "mileage checks" were done the same way. Start out with a FULL fuel tank (meaning CAREFULLY adding the last few gallons to make SURE the tank is actually FULL).

Road conditions are paved, hilly, with long up and down-grades ( Arizona State Highway 89 from Prescott to I-40; then I-40 to Los Angeles & return. (I make this trip about once a month to attend to my business in Southern California). Overdrive "locked out" except for VERY level sections AND no head-wind!).

I cruise at 65 mph ( obviously cant keep that up on the grades; down to 35-40 mph on the worst ones). I try and avoid full throttle operation, shifting from 3rd to 2nd manually BEFORE the trans. down-shifts on its own.

Start mileage 25,006 (Paulden, AZ) End mileage 25,434.5 (fuel stop; cant read my own notes as to where..!) Gasoline back to a "full" tank took 35.5 gallons. ACTUAL fuel mileage 9.32 mpg. INDICATED mileage 9.3. That's "dead accurate"..folks.

Start mileage 26,756.3 (Paulden, AZ) End mileage 26,921.4 (gas station on I-40 just east of Calif. border, at AZ 93 turn off). (now, to be fair, this was pretty much a down-hill run, with a tail-wind, explaining the exceptionally good mileage for a heavy tow). 165 miles, fill was 15.79 gallons. ACTUAL fuel mileage 10.45, INDICATED mileage 10.4. That's "dead accurate" folks.

Start mileage 27,092.4 (Barstow CA) End mileage 27,262.6 = 170 miles; bought 17.1 gallons to "full") Another essentially level to down-hill "run" into Orange, Calif., ACTUAL mileage 9.95, INDICATED 9.9. That's "dead accurate" folks.

As I have noted in earlier "posts" (where some kid has complained he has conflicts between what he THINKS his mileage is, and what he sees on the over-head mileage indicator) I have seen INDICATED gas mileage as high as 20 mpg on some down-grades, and as low as 3.5 mpg on REALLY rough steep climbs.

The "trick" to all this is recognizing the over-head indicator is simply a computer AVERAGE of fuel use over whatever time-period it is programmed for. I have won a beer-bet demonstrating I can "trick" the computer into indicating just about ANY fuel mileage I want, by using it incorrectly.

 

When you get low on fuel, it automatically changes from MPG to miles to empty, as well as an audible alarm will sound, to let you know you need fuel. This is normal operation. I use my overhead for mpg, and generally it's pretty accurate. I reset it every time I get fuel and it shows my avg mpg off the bat, and it adjusts with my driving style.

 

Sorry, mine's not "'dead accurate' folks". Glad yours is.

Over the holidays we drove about 2,500 miles round trip. The first tank indicated 15.6 which is way over optimistic, hand calculated more like 15.2. Every time it was always a little optimistic. Overall we avg'd about 14.8. Which, if you ask me aint too bad for a V10 powered 7,000lb+ truck running 70 - 75 MPH

 

Mine is pretty accurate calculating the MPG. However, if I fill completely up when it shows "0 miles to empty," I can only get in about 36 gallons or so. It is really haunting to drive with that readout telling you that you are out of gas.

 

Just noticed mine do what you saw the other day It seems to flip over to miles left when it hits 50 Miles remaining

Cheers

 

I don't know about most, but I'd say reading 15.6 vs 15.2 actual is pretty close. As long as it's within 1mpg I'm happy. I also rarely let mine get below 1/4 tank too. Never know when fuel prices are going to rocket again, i'd rather fill 1/2 tank with fuel $0.20 more than the last, than a whole one.

 

Yeah thats what mine did at 49 miles left. Ok well at least it's working as it should.

Thanks, T.Moe

 

Ok. I do the same thing when I fill up. Good to know it's not going bad.


Thanks, T.Moe

 

IMHO, between the readings you reported, I would be more inclined to trust the on board computer than your hand calculations.

There are a lot of factors that skew hand calculations - difference in pump readings (by law, they can be as much as 3% off - studies have shown they are commonly greater than that), difference in the 'click off pressures' (again, they can varry greatly), position of the truck when filling (inclined up or down), and ambient temperature when filling.

The on board computer is counting injector pulses - which it knows 'exactly' how much it is 'squirting' everytime. With that info, it calculates based on the distance traveled.

About the only thing that will throw it off is if you have changed gears or tire size and therefore have an inaccurate speed odometer or maybe non-oem injectors (not sure about that though).

 

Wow, 6686L actually posted an informative and useful post, I think he deserves a round of applause.

 

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I am insulted. You are trying to cheat me. I am entitled to applause NOT just because of my incredibly accurate and informative info; what about my charm, good looks, sweet, pleasant disposition, and all around "really nice guy" status..?

 

Hey Pete, don't forget about that little 'ol weenie thing!