CoachRick

So, yesterday, as a bit of an experiment, I let the fuel tank run down to a level that showed '29' miles left on the range indicator. The tank level appeared to match, so I wanted to add just a bit of fuel to get to a particular station for the complete fill-up.

I added just over a gallon to the tank(range showed 27 miles at this point) and set off on my errand. Interestingly, the range didn't change when I re-started; but I thought it might need to reset. Drove about 6 miles and the range continued to count down from the original(started at 29 miles, if you're following me). Re-started the vehicle a few minutes later and it still showed the range miles as in the low 20s at that point.

As I made the trip to the station to fill up, the mileage counted down, still as though I never added the 1+ gallon. The fuel gauge did seem to operate properly, although it's tough to read a one gallon increment with any accuracy.

When I filled up, the auto shut-off kicked in after 13+ gallons, so the gauge was pretty close, but the range indicator was less than useful, IMO.

Bottom line, don't push it when the range readout shows you have X amount of range left(or don't panic when it shows the opposite ).

BTW, after driving in Atlanta for most of 3 decades, I've learned to keep at least 1/4 in the tank. You never know when you'll be stuck in gridlock for hours. Letting the tank run so low this time was a one-off experiment.

CoachRick

As a bit of an update, the fuel gauge and 'range' indicator seem to function properly when I filled the tank; but I will take caution when the indicators approach very low levels.(You'll recall that I don't run the tanks to 'fumes' typically; but DW has been known to leave me the vehicle with nothing but vapors in the tank ).

aks1972

what i dont know is if the range counts down to empty or to the "reserve"?

I normally fill up whenever the light comes on. The fill up ranges between 13.5-14.5 and range indicator at that time is usually in 30's.

How can it be if I have 2+ gals still in tank as my regular mpg is between 23 and 24.

dalmeida

This is just anecdotal but I've been getting about 19.5 mpg city with a lot of stop and go for it's first 500 miles. I have a lead foot as my wife will attest she does much better. Forgot to fill up yesterday morning and took the 10 mile drive home with the gauge at 40miles range left thought I had plenty. By the time I pulled into the gas station a half mile from home it read 0. I filled up with slightly over 15 gallons. I think it was 15.1. Needless to say I won't trust the gauge on the low end.

geocord

I forgot to check the range display but I just drove about 15 miles after the light came on and could only get 13.6 gal in at fill up. Guess I could have went another 20-25 miles easily.

CoachRick

Well, my darling and I combined to run both vehicles a fair bit past the light coming on; but, both the C70 Volvo and the RDX look like they have 2 gals+ when the indicator comes on(according to the range and the amount each took at the pump). My concern is the variability of the readings once the tank gets below say...1/8 tank. I still try to keep to my own recommendation of not running the tank much below 1/4 full...just to be on the safe side. We don't have the nasty gridlock-any-time-of-day here in Austin like we had back in Atlanta...but it's still not a bad idea to re-fuel before getting down to the fumes!

paflyboy55

I realize this is an older thread but just wondering if anyone has had the same issue as I do. The range indicator seems to be working fine. Every time I fill up it resets but the fuel gauge is always on zero with the light on. I'm assuming since the range indicator works the sending unit is good. Could the gauge be bad or should I be looking for something else?

Skidoor

since the light is still on, I'd say its not the gauge, pretty sure its whatever device sends the light signal and the gauge signal...probably some ECU in there somewhere. (electronic control unit, not engine control unit)

let it go...too expensive to fix for an '03

YeuEmMaiMai

with most cars, E is not really empty, gas tanks typically contain enough fuel to keep the fuel pump cool even when "empty". running the car down like that all the time is a good way to ensure you will need a new pump sooner rather than later.[img]

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Be a certain point, the fuel guage will no longer register even though there is gas in the tank[/img]

jim_c

The MID will display a range remaining which is based on instantaneous consumption. Thus the range displayed will fluctuate quite a bit. I try to fill up before the range gets below 80 or 90 km (50 miles or so).

RDX-Rick

I believe that the range is calculated by using the average MPG during the last 20 miles. (approximately), and the current amount of fuel in the tank. If it were using the instantaneous consumption, we would see our range drop to just meters whenever we floored the pedal, and jump to 1000's of kilometers when we were coasting,

I often take trips of several hundred kilometers in my RDX, and when I arrive at my destination, the estimated range shows that I have enough fuel to return home. However after driving around the town for a few hours the estimated range drops so low that I would not be able to get back home without refueling. But once I get back on the highway for several miles the range gradually increases as I drive further until the estimate is high enough to get me back home. At some point the estimate stops increasing and begins to fall as expected when we consume fuel.