reserve fuel
 

How much gas is left in the tank when the reserve fuel message appears on the DNC. The DNC was showing I had 103 miles to go before I would run out of gas. It was showing that I had averaged 30.9 MPG with interstate driving at 75 to 80 mph.

Reserve light comes on at 3 gallons left.

Thanks for the information that would work out about right for my gallons left and the mpg I was getting and the miles left before I run out of gas. I was trying to get back to my non ethanol station to fill back up but did not want to take a chance of running out on the interstate last Saturday.

For best results fill up when you reach 1/4 tank. This will help avoid the dregs from the tank flowing through the fuel system.

And it keeps the pump cooler which makes it last longer.

Because my driveway is so steep, it seems I'll park it with 1/4 tank and when I leave for work, it's on "Low Fuel", I always hit the gas station before I head out, its on the way to the highway.

But I have gone close to 80 miles on reserve before. Far less than ideal, but it does happen.

mine pops the reserve fuel warning when the computer calculates my range is 50 miles, based on the current average MPG.

so yea...about 3-1/2 gallons ( @ 15.x mpg city )
or
30-odd mpg as user bop states

Why would anyone run their tack that low on purpose? It's hard on the fuel pump (it's immersed in the tank and needs the cooling) and you also suck the dregs through the fuel system. There is no good excuse!

This is especially important. I always try to fill up when I have no less than 1/4 tank left.

:iagree:

:iagree: with those who mention the fuel pump. Best to keep it immersed to keep it running cool.

:iagree:

Ok, two questions...
First, how many gallons in the tank does it take to cover the pump? Reserve is 12L, call it 3.2 gallons, and 1/4-tank is 4.5 gallons, only about 5 quarts difference. I usually start planning the next gas stop at 1/4, but around town that's only about a 20-25 mile window.

Second, how hot is the pump designed to run anyway? I'm thinking 100+ day in Phoenix, exhaust pipes running right past the tanks...

I also find myself wondering how much early filling helps with the dregs. Seems like the dregs don't stop building up because you fill the tank more often: eventually the dregs will accumulate to whatever arbitrary fill-up point you select. The fact that there's no easily-replaceable fuel filter in the system is also a bit disturbing.

Upon further review, we may be overthinking this...
The fuel pump pickup is at the bottom of the tank, right? Where the dregs are?

And wouldnt you think that at 1/4 tank even, the fuel is low enough that it is sloshing from side to side in turns, which would stir up this "dregs" and make it suspended in the fuel. Also the fuel pump is in a sump at the bottom of the tank so it doesnt suck air in cornering when the fuel is low. So as long as the car is still running, the pump is still under fuel.

Tank has baffles inside that keep sloshing to a minimum. The motor (bearings) are above the pump so it is going to affected by lack of cooling fuel first.

Personally, I feel 1/4 tank is the bare minimum to keep the motor cool. I have noticed the pump gets louder as the gas is being used up. 1/2 a tank sounds like it is not covered to me. I'd love to know the exact position if anyone knows.

fuel is heavy, that's why

I have a 40+ mile commute and if I take the long way (Skyline Blvd), I have a 40+ mile stretch along the ridge of the west hills. I average 65mph (3rd/4th gear) along that stretch and the nearest GOOD gas station is a solid 15 miles PAST Skyline on my way home.

I prefer to get gas at Skinnys (Shell) in town I am often caught 40+ miles away from there when I notice I am at a 1/4 tank.

So yeah, it happens.

<edit> If running at or bellow a 1/4 causes the pump to fail, then that is a piss poor design. Should have made a bigger tank. :rofl:

<edit2> I fill up on average 3 times a week with my commute, the last thing I want to do is go to the gas station MORE.

Your half-full tank is a 9-gallon air-cavity resonator.

If the pump requires a certain amount of gas covering it to cool it, a competent engineer would put the reserve limit above that point. If you want to imply that the C5 design engineers were incompetent, be my guest...just let me get out of the splash zone first.

:iagree:And am I really the only person on this forum who has owned a car with an electric fuel pump that was outside the tank?