phoneman91

I just know that someone has driven one of these C5 dry--ran it out of gas. How many gallons did it take to completely fill dry tanks?

I have never fillled up my C5 and placed more than 15 gallons of gas into the two tanks. Even when my warning light was on.

I presently have only 1/8 tank left--and the DIC says that I have a range of 115 miles still. And my average MPG on that tank is 28.4MPG. If the tanks should hold 18 gallons--1/8 of the tank should be 2.25 gallons. And the DIC says that I have a range of 115miles--from just over 2 gallons?

And it seems that the second half of the gauge goes down faster than the first half of the gauge. Is there a built in "safety net" into how the gas gauge is calibrated--it is actually pessimistic between the half full and empty part of the gauge ?

phoneman91

I understand that the fuel pump uses the surrounding gas as a coolant. But there are times when you are in the middle of nowhere ( or Kansas)and it is necessary to know how much actual fuel is left.

What is the most gas pumped in a single fillup in your experience?

And I think that my tricky DIC is lying to me. 2.2 gallons left and still have a range of 115 miles?

dadaroo

How long it takes for you to be out of gas to run the engine depends on whether the jet pump in the passenger tank is working.

phoneman91

I appreciate everyone's response.

But--no one knows how the fuel gauge can show 1/8 tank left and the DIC shows 115 mile range left? With 28.4 MPG average on that tank. Is this range estimate accurate?

I suspect that there is a reserve of gas that is left in the tank --even though the gauge shows just 1/8 tank--approximately + - 2.2 gallons. It would seem that there is actually more than 2.2 gallons left. The amount of this reserve is apparently unknown to all of us .

And I was just wondering if anyone knew actually how much gallons it would take to fill both tanks from empty. 18 gallon tanks or 2001 MY 18.5 gallon tanks.

Fast one

I ran my '98 dry years ago to check the gage and it took 19 gallons to fill. Once I ran out of gas and it took two gallons before it would start so now there are two emergency fold up jugs in the trunk in case it ever runs out again.

phoneman91

Thank you! I just knew that there had to be someone out there that ran these tanks dry.

Apparently there is a untallied "reserve" and the analog gauge doesnt reflect this--but the DIC range estimate mileage does. And this reserve is the reason that I can have a range of 115 miles left on an indicated "1/8 tank". The analog gauge is lying and is pessimistic.

The owner's manual only states:

"When the needle approaches the “E,” LOW FUEL
will appear on the display. At this time, you still have a
little fuel left, but you should get more soon."

Fast one

I think that a dirty, restrictive fuel filter is responsible for more failed pumps than running the tank dry a few times. A restrictive filter places continuous extra stress on a running pump; my fuel pump is original with 116,000 miles on it but the fuel filter has been changed several times. After the gas gage let me run out I use the trip odometer and fill the tank around the 200 mile mark.

Yello95

For the past 11 years I have almost always filled up when it reached half capacity..but that's just paranoid me...btw...mine says it has 18.5 capacity...

Lee DeRaud

You know, you might actually get some useful information if you went to the gas station now with 1/8 showing on the gauge and see how many gallons it takes to fill it up. Just sayin'.

dbarrym

Hmmm... i have filled up with reserve light/check gauges warning on, DIC stating >20 mi range, and only added 15.6 gallons...'99 FRC.

Barry

Lee DeRaud

On my '04, the "reserve" message comes up when the estimated range drops to 50. The only times that ever happens are on tanks around town when the mileage is low anyway, so it usually only takes 14.5 or so.
(The day I brought it home, it took 16+...I think the dealer was putting in a quart or two whenever it went out for a test drive.)

phoneman91

I ran it down to the last hash mark before the red zone. I had 109 miles of range left--with an average 28.4 MPG on that tank fill. And it filled up with 14.4 gallons. Apparently I have a 4.1 gallon "reserve".

Thanks everyone for their responses to this thread. I usually do not run the tanks on my vehicles this low--but I like to get a sense of how true the gas gauge is on each vehicle and know how much reserve I have when the gas gauge shows the "E".

And I agree that keeping the tank full--leads to a longer life for the fuel pump. I have owned used vehicles that have had the fuel pump last twenty years/150k miles and more--that have had owners that didn't allow it to run with low fuel level.

The fuel pump is in the driver's side tank and the driver's side tank is the last to empty--and even when the gas gauge was on the last hash mark--the driver's side tank was just slightly less than half full--and would have kept the poor fuel pump covered in cooling fuel.

If the fuel gauge is calibrated on all C5s like mine--the driver would have to run it for at least 80 miles past the last hash mark--before running the poor C5 out of gas. Good to know.

xwing

There's a little reserve on every car. I used to drive all my cars well below the "E", until I pushed it a little too far a few years ago and had a nice hike in hot weather.

Corvette#2

I've ran mine all the way to E a few times.

But the most I have ever managed to put in the tank is about 16.75 gallons. I think it's supposed to hold 18.5. The reserve fuel might not be accounted for. They obviously don't want the engine to stall out the second the needle hits empty.

I've also noticed the analog gas gauge doesn't appear to track linearly. When I fill up, it takes a long time to hit 3/4, but once it's down to 1/4, it seems to hit E more rapidly. Just my anecdotal observation.

phoneman91

I have noticed that also. And the fact that the gauge goes quicker from one half to E than it does from full to one half. But if there is a hidden reverse of 4 gallons or so--it would explain this.

phoneman91

I agree that there is a reserve of some amount in all cars. Just a matter of finding out what the reserve is. Many car's owner's manuals will actually state the reserve. No so the C5 owner's manual.

scarecrowkc5

I put 15.85 gal in mine today.

The reserve light had just come on 5 miles before I filled it.

Studying4boards

If you REALLY wanna know....Take the practical approach. If you are not afraid to let your tank run dry, take a 5 gallon fuel canister with you and then just drive until the car stops. Calculate the miles. Pull over, put that 5 gallons in the tank and be on your way.

If you are in no man's land where you don't know when you'll reach the next gas station, what I do is plan ahead and fill up before going through that area.

If you do this experiment, do post the results please. Would be good to know if that DIC was accurate.

StrangelovesM6Vert

You can also use the trip odometer after filling it then see where it is when you refill it.
You can accurately calculate your mileage after monitoring a few tanks.
With that info you can figure out how far you can go based on the tank capacity.

scarecrowkc5

My vette burns more fuel in town than on the highway so my mileage is from 24 mpg to 28 mpg per tank. It just depends on how much I do of either ... so I wouldn't count on the miles left to empty theory.