Is there a low fuel warning light or something? I got all the way down to 24 miles cruising range this morning before I gave in and filled 'er up anyway. Not a biggie, really. Just expected something to happen at maybe 50 miles remaining. She's so doggone smart about everything else that I just assumed she would also tell me when to stop for gasoline.

 

Light comes on at about 20-25 mi point, each vehicle is different. But once it gets to ZERO you still have 2+ galleons in the tank. Have run mine to beyond zero several times.

 

I have to tell you all a story about the tank light.

With my RX300, I once took a very long and scenic trip (20 hours) from San Antonio, Texas to Mexico City, Mexico via Highway 85 through the wildest roads I've ever been through until I finally reached a town called Zimapan in Hidalgo State to reach a Pemex Station (and by the grace of god they had Premium gas, 92 octane). I was a good 50 miles on the tank light before that and not a single gas station in site (or even a small village where they sell gas out of a drum). That tank light looked like a UFO in that Mexican sky with not a single car around me. Not too long ago, Google on their Google Earth mapped that road and this is the kind of thing I saw for miles with no other civilization but the road around me (and it was dark for most of the time I was on this road),

http://maps.google.com/?ll=20.824159...80.57,,0,10.15

I swore I'd never take that scenic route again (it's like taking the Pacific Coast Highway and sticking it in the middle of the San Joaquin Valley).

Even though I had a Garmin eMap with me at the time (July 2002), it was no consolation for driving with no AC, keeping my foot constant on the pedal to save gas (I couldn't use cruise control given the mountain roads).

So, yes, you can go a bit on that tank light

 

She's smarter than that. She just stops in the middle of the road and forces YOU to go for gasoline. But yes, there's a low fuel light and the only time it lit on me it was at an indicated 24 miles cruising range.

JB

 

the lowest ive taken our 2004 Rx330 is 3 miles ahowing on the range.... is there really 2 more gallons after that? thats another 40 miles... woo hoo!

 

I never run my gas that low because I don't want to risk overheating the electric fuel pump in the gas tank. Normally, the pump sits on the bottom of the tank immersed in gasoline to keep the motor cool. If the gas level is too low (ie, exposing the pump), the unit may overheat and burnout. I am not sure but I am assuming my RX350 fuel pump sits at the bottom of the gas tank.

 

^As far as the electric pump overheating, we had our corolla for +10 years and only filled it when it's at the E with the light on for awhile, never had any problems.

 

Getting gas before it drinks it's last gulp is good, but running below a quarter tank on a consistent basis can have drawbacks. No matter how well it's filtered some trash and or water in minute particles gets into the tank. Overtime it becomes a larger amount. When you run low, there is the risk it gets picked up by the feed. The gas filter will clean most of it, but if there's enough it will clog and some may pass through.

If no one has ever had to have injectors replaced because water got through, it's not cheap, I've done it in the past. Any water at all will ruin the injectors. I had to replace all of them, the fuel filter, and have the tank removed and cleaned.

I'm so paranoid now about water, I keep my gas receipts at least until the next fill up in case I have to prove where the bad gas came from. This was a car in the past, but it's not a memory that fades very well.

 

The "cruising range" number is, on my cars, and I gather this is a universal setting, unrealistically low. If I wait until a light or a digital readout warning of low fuel, a fillup is usually 2 or even 3 gallons less than the capacity of the tank, which would be in the 40 to 50 mile range. It's a long ride of faith to even test out the warning lights, as the gauges get down to and even past "E" before sounding alarms.
Accurate gauges are for airplanes where pilots are all well trained and can be entrusted with accurate information (and where there is a substantial penalty for running out of gas). Auto makers seem to posit a lower level of initiative in most owners.

 

Cruiter you are right on the mark.....by allowing your tank to drop so low the filter will not be able to filter all the sediment at the bottom of the tank. I don't think you want that sediment drawn thru your cars' system.

 

I just filled up my RX and the dash tells me that my cruising range is 250 miles, which is, of course, way too low.

 

Wow. Even if you get 19 mpg and there is a 19.2 gallon tank you get 364.8 miles on a full tank. I need to check where mine registers next time I fill it up. Which was 30 minutes ago but now the wife's got it out fetching groceries so there goes that opportunity. But it does raise the quesiton what mpg does it use to calculate your range? Overall mpg unless you reset it?

 

I'm not sure where the car gets the data to compute the range, but on the several Lexus cars I have had with this feature, the displayed information is always overstated, surely in an effort to get me into the station before I run out of gas. I don't mind the effort, but the information, and even the gas guage itself, is so far off that it's almost funny. The tank holds about 20 gal. Fill it up sometime when the needle is right on the half way mark, and my guess is that it will take 7.5 gal. When I fill up at the 1/4 mark, instead of 15 gal, I usually am able to pump in 12 or 12.5 before the pump shuts off. In my opinion, the margin of error is far too large. But that result is a lot better than if the car ran out of gas before the needle hit "E."

 

Car drivers are not airplane pilots who will act on the information shown on the fuel gauge as if their life depended on it. Soccer moms would not be happy if their Lexus range ticked down to zero and then the vehicle stopped alongside of the road. Car makers aren't stupid so they add in a bit of cushion, I would too if I was them. I've never seen any vehicle that had a fuel range gauge that drained the tank once the range read zero.

I don't believe the talk of overheating the fuel pump or drawing sediment through the pump, there is enough agitation and settling of any material in the fuel that you getting it through the system as a natural occurence. Fuel today is pretty well filtered by the time it goes into your tank and you have a final fuel filter before it gets into the injectors. It's more a theoretical problem than actual, imo. For those that wonder how the range is calculated, it is done after approx. two gallons is removed from the calculated fuel remaining in the tank, using the actual burn rate of the engine. It is easy to find out how much fuel is actually in the tank as it ticks down. Run it down to zero and then fill the tank, you can't put more than 17.0 to 17.2 gallons in the tank with it showing 0 range. If the specs are accurate and there is a 19.2 gallon tank capacity you are left with about 2 gallons in the tank. This would give about 50 miles, a reasonable distance for someone to find fuel and avoid completely draining the tank. I think this is a reasonable approach.

 

Also, there is probably a residual amount of fuel that might remain in the tank and be unable to be drawn up by the fuel pump. In the olden days, when low on gas, I would get some sputtering when going around a corner due to fuel being moved away from the fuel pump intake. With modern designs, this does not happen, I think, (or maybe I buy gas more frequently these days), but surely there is some amount unavailable to the car, which is a factor to be considered, although not a great one.
I gotta go.