: Gas Tank Question



abbas
09-13-09, 10:58 PM
From the CTS-V specs, it says that it has a 18 gallon tank. Today, I drove the car until the gas gauge was probably at 1/64 (a tick off of empty). When I filled the car, I maxed it out to 14.7 Gallons. Based on this, I assume, when the car's gauge hits empty, it will have another 3 gallons in the tank. Can anyone confirm this?

Also, I would like to say that I dont like the fact that when the car gets low on gas, it doesnt tell you how many more miles you have left to drive but instead 'Low Range' is displayed. What is up with that! :hmm:

marktanner
09-13-09, 11:32 PM
I can vouch that the tank holds 18 gallons. The level at which the low fuel warning comes on varies from car to car, in my experience. On my '08, there was four gallons remaining, but in my V, it's only two gallons. I agree that the range available is pretty useless. IMO, you really need to know the precise range when you are low on fuel, and we don't have that info. The SRX has a useful "gallons used" feature in the DIC that I wish we had.

ewill3rd
09-14-09, 06:40 AM
Most of our gages do not regsiter the first 1-3 gallons.
I would never tell you when your gage reads E that you have 3 gallons left.
I always advise people to fill up at their earliest opportunity after the gage reaches 1/4 tank.
Why would you want to do anything different?

MReiland
09-14-09, 06:51 AM
I was always told by my old family mechanic in Milwaukee that (and this may have been only for older cars) the fuel pump that resides in the tank is cooled by the fuel and you should try and keep 1/4 tank of gas to keep it at the appropriate temp. Going all the way to empty all of the time could lead to premature pump failure. This might not apply to modern vehicles and especially not to ones with an external fuel pump to the tank. I try not to go much below 1/4 just because I seem to have a knack at hitting a major road disaster precisely when I am low and gas and end up idling for an hour while it clears......

stealthjr
09-14-09, 09:25 AM
I was always told by my old family mechanic in Milwaukee that (and this may have been only for older cars) the fuel pump that resides in the tank is cooled by the fuel and you should try and keep 1/4 tank of gas to keep it at the appropriate temp. Going all the way to empty all of the time could lead to premature pump failure. This might not apply to modern vehicles and especially not to ones with an external fuel pump to the tank. I try not to go much below 1/4 just because I seem to have a knack at hitting a major road disaster precisely when I am low and gas and end up idling for an hour while it clears......

You are 100% correct. Consistently taking your tank to empty (or near) is an dead fuel pump waiting to happen. The pump is cooled by the fuel in the tank and without enough fuel to keep it submerged, it will start to overheat. Obviously, it may not burn up on the first or second adventure below 1/8 of a tank...but I can tell you from experience...your pump will suffer and eventually burn up.

I don't think you must fill up at 1/4 of a tank...but I sure wouldn't let it run very long sitting next to the empty line. Personally, I never let it get below an 1/8 of a tank and prefer to fill up just as it passes the 1/4 mark.

I'm not sure the point of running a gas tank so low anyway...but to each his own.

Good luck!

Robert

neuronbob
09-14-09, 09:39 AM
Prematurely worn fuel pump definitely does happen to modern vehicles still, and so I gas up when I get to 1/8 tank or so.

NeedCTS-v
09-14-09, 11:06 AM
I also never run my tank to empty just to prevent excess debree from the tank clogging the fuel system.

Looney100
09-14-09, 07:00 PM
I also never run my tank to empty just to prevent excess debree from the tank clogging the fuel system.

Gasoline is incredibly light, therefore any water, debris, etc. will be heavier than the fuel and will reside in the low-point of the tank - where the pump also pulls its fuel from. i.e. running low on fuel won't cause any excess debris from getting into the fuel system. With the exception of rust that may cling to the sides of a metal tank, most contamination that enters the tank is pulled through the pump almost immediately.

rocketeer
09-14-09, 11:13 PM
I agree that Low Range is useless but on a trip to Canada this summer I knew I was low and wondering where in upstate NY in the middle of almost nowhere I was going to find gas. Surprisingly the nav system popped up with a list of stations within a range of 11 miles with ensuing directions. I dont remember exactly but it was a bit over 15 gallons it took.

abbas
09-15-09, 12:13 AM
The car guzzles gas. It seems like I am pumping gas a few times a week. It would be nice if I could drive the car and extra day before I have to fill it again. If I have to fill at 1/4 tank, I will be at the gas station at least every other day.

ewill3rd
09-15-09, 08:41 AM
The real victim in the fuel tank from constantly running low fuel is the fuel level sensors. They are ceramic plates with metal contacts riding on them. The fuel keeps them wet and smooth, when you keep them dry the metal gets eaten off.
Look at all the Devilles and Sevilles. I have a lot fewer complaints from people who fill their cars regularly. The $5 and $10 crowd come see me a lot more.
(nowadays it is probably $10 and @20 I guess)

GM doesn't even make metal tanks anymore I don't think. The composite plastics are in everything I work on. The fuel pump is actually always immersed in fuel due to the design of the fuel sending module in the tank so essentially as long as it can get fuel it will stay soaking in it.
CTS has 2 fuel level sensors and taking the tank out is a royal PITA. Labor for replacing the fuel pump or level sensors is almost 5 hours by whatever your local labor rates are. That is about $600 around here plus the price of the parts. Food for thought.

Trace amounts of water and debris will always be an issue but there isn't much you can do about it any way. It doesn't matter what the fuel level is, if it is in there it will find its way to the pump.
My "evil" SUV will go for almost 3 weeks without requiring a fill up, but I don't have much of a commute, it's only like 4 miles one way.

inkpump
09-15-09, 10:35 AM
I also agree the "LOW RANGE" message is annoying since its a relatively simple calculation for the computer.

I once had the NAV system pop up like "Rocketeer" however it hasn't done that for a while.
Does anyone know if that only works if you have a route setup or will it work just by having the NAV page displayed?

ewill3rd
09-15-09, 05:44 PM
Considering that it cannot read the first 1-3 gallons then it seems like it might not be such an easy calculation.
From the manufacturers standpoint, why do they want to tell you that you have 10 miles left to drive when a sharp turn can cause you to stall the engine out and have a wreck?
Just get some gas... :lol:

abbas
09-17-09, 01:48 AM
Considering that it cannot read the first 1-3 gallons then it seems like it might not be such an easy calculation.
From the manufacturers standpoint, why do they want to tell you that you have 10 miles left to drive when a sharp turn can cause you to stall the engine out and have a wreck?
Just get some gas... :lol:

Leave 1 to 1.5 gallons as insurance in bottom of the tank but allow the rest to be shown in the display.

For me, I really dont care that a full gas tank can go 200 miles but I would really like to know how much more I can drive when the gas gets low.