Gas level question

[supertrooper9]

Hey T4R folks, I have a quick question and was hoping some of you can help explain this little "mystery" to me

I wanna get to know my 4R better (2005 sport), and I have a lot of the mechanics and quirks figured out, but gas efficiency has alway boggled me. I seem to be losing a bit of gas each parked interval and I'm not sure how normal that is. For example, I would park my vehicle, see the gas meter at a certain range and read the estimated remaining mileage. The next time I start my vehicle, the gas meter would be lower than when I parked it and so does my estimated remaining mileage. It would almost seem as if the car was running while I was away. I doubt it's a leak, but it's like it just evaporated.

At a full tank, my estimated mileage always shows 420+. I drive non-aggressively in a flat city, with my estimated mpg always reading 21+, but in reality, I never get over 380miles on a tank....what happened to those 40 that I supposedly had? And is it normal for my mpg reading to be 3-4mpg too high???

 

[JayKumar]

420+?!?!?!? WTFF be glad! I BARELY get 350 or so. But maybe your computer is reading out wrong because thats a high number. Im sure there is no leak. You should try to reset your system by pulling the two fuses under the hood in the fuse box...i think they're called ECI fuses. not sure. they arent relays.

 

[supertrooper9]

My first tank of gas ran me almost exactly 420...it's been 4 months and now I can't get more than 380. So.....I don't know what's up.

 

[PlanetAlaska-]

I don't think you have any problems. The range is only an estimate and is not an exact science. I also notice the same thing as you.

 

[HB 4X4]

You're gauge is just reading the fluctuations in the expansion/contraction of your fuel. When you drive, it warms up and your gauge will read higher as the gas expands. You aren't losing any gas while it's parked, it just takes a while to warm back up. You are comparing the warm reading to the cold reading.

 

[toto]

Keep in mind that the trip computer is not very accurate... there are many threads here about the MPG being about 10% too optimisitic, and also about how much gas is in the tank when you refill it affects the range calculation. I wouldn't analyze what it says too much. I leave mine on Outdoor Temp.

 

[chaz]

380 is still good, be happy

 

[Nuke]

You're gauge is just reading the fluctuations in the expansion/contraction of your fuel. When you drive, it warms up and your gauge will read higher as the gas expands. You aren't losing any gas while it's parked, it just takes a while to warm back up. You are comparing the warm reading to the cold reading.

+1. Fuel will expand and contract with temperature.

And the on-board typically is off conservatively by about 2-3 MPG. Hand-calculate and just use the on-board for relative info.

Most of my driving is rural and about 25 miles one-way to work and then about 5-10 miles of in-town driving once or twice a week. I tend to average 23.4 MPG per the on-board and 21 MPG hand calculated (and although I never look at the "Miles to Empty" garbage reading, that would equate to 538 miles per tank per the on-board and 483 miles per tank per reality) on my V6.

 

[supertrooper9]

Thanks for all the input folks, I really appreciate it.

P.S. Gas prices have been going up for 3 weeks now around my area. It sucks!!

 

[JMST4R]

Just something I've noticed about the gauges and readouts on the 4R, or at least on my '06 Sport V6: my odometer is actually off by about 15-18 miles at the end of a full tank. My navi tracks my drives to within 3 feet, which I find interesting (I also believe it to be more accurate than my odometer). Probably just because of the tire size on my 4R, but still something to consider.

 

[Nuke]

It's pretty much a given that the typical vehicle's odometer is off by some percentage compared to a GPS obtained value. I don't know about the T4R, but I can change the PCM values for gear size and tire O.D. on my Mustang using my tuner.

 

[JMST4R]

It's pretty much a given that the typical vehicle's odometer is off by some percentage compared to a GPS obtained value. I don't know about the T4R, but I can change the PCM values for gear size and tire O.D. on my Mustang using my tuner.

Yeah, that's for sure! They're never right on. I was just a bit surprised when I bought my 4R, and was hand calculating for a month, then bought the AVIC X920BT, which has a built in fuel calculator (so it can dreadingly tell you how much that jaunt across town will cost), and it was telling my how far my odometer is off. Now I only use the one on the navigation. It's really intuitive.