What is "True" Petrol Empty?
 

I now live in NC. Gas stations are much more common in CA than they are here. I was on an excursion yesterday/evening. My "50 Miles to Empty" warning came on. My GPS said home was 39 miles away. Wasn't too concerned.

GPS routed me to a dirt road. :-( I don't do DIRT roads. Changed course. So, here it is DARK in NC and "miles to empty" kept updating me, and gas stations didn't appear on the horizon. Could have/should have checked the GPS for nearest gas stations, didn't.

Long story short, I filled up when the "miles to empty" said I had about 12 to 14 miles left, don't recall exactly. It took 15.44 gallons.

Anyone found out what TRUE EMPTY is?

I could have checked the "Gallons Used" as a double check, 99% of the time when I compare reciept to that when filling the two readings are within a couple of tenths of a gallon. This time it was a gallon off, and would have given me false hope if I had looked at it. Must have omitted to reset it a the last fill up. Also, my average MPG for ALL driving in NC for 2008 is 19.97

1) Don't trust the onboard computer. It's historically inaccurate.
2) Don't let yourself get that low, knowing:
a) "Gas stations are much more common in CA than they are here"
b) You don't want to suck the garbage out of the bottom of the tank

We have a 16 gallon fuel capacity. I would think when the tank is empty, that would be "True Empty"... (ya' think?)

Not going to disagree with you. Should have filled up earlier. Didn't really think the excursion would chalk out at some 120 miles, I was thinking 80 - 90 miles when I left. Didn't really plan for the route I ended taking on the way back, I had figured there would be a station on the way.

However, "True Empty" - when the car runs dry because it can't reach that last portion still in the tank. On a GT that could be with a 1/2 gallon remaining, but I don't know.

I've heard for years the story about garbage in the bottom of the tank. My last car was a BMW, 29 years old, 269,000 miles, when I sold it. You could look into the gas tank by pulling the back seat bottom and doing a quick operation to pull the fuel pump and filter. EVERY time I did that, the tank look brand new inside. My '89 GMC PU with 172k on the meter a few months ago needed a new fuel pump. Its in the tank. Mechanic told me the tank was perfectly clean inside.

I only fill at good gas stations, but, I wouldn't fill up if the delivery truck was making a delivery unless I had to do so.

when the car says "0 miles to empty" you have about 1 gallon left

First you dont have to worry about sucking dirt up into the pump if you have some at the bottom of your tank. All these cars with electric fuel pumps have pre-filters on the pump. Usually called "socks". Second running a on an empty tank can severely shorten fuel pump life. Not only does the gas act as a lubricant for the fuel pump but it also keeps the pump cool during operation. We wouldnt run our cars without oil or coolant so why would you want to risk it just buy squeeking out every last drop of the tank. If you own a s197 your not broke usually, keep that tank at 1/4 or more at all times.

I also think the computer may not be perfectly accurate. I've had it tell me 25 miles to empty but when I went to fill up it would only take 13.5 gallons. If it's a 16 gallon tank that would mean there should've been 2.5 gallons left which would provide for significantly more than 25 miles of travel.

Something isn't right with that picture.

weird... i've gotten down to "1 mile left" and when I filled up it took less than 15. I thought that we had a 15 gallon capacity.

16 gallons per the manual. I hand calculate at every fill-up and the # of gallons used per the gas pump is typically about 1 gallon or more than the computer and I've heard that from a lot of others. Use the on-board info for just that, info.

I would suspect the gauge is the best indicator for actual fuel level.

It's kind of scary the way it alerts you. At around 7 miles to empty you get a beeping noise and a flashing light on the dash along with what the computer read out tells you. What I noticed about the whole thing is after you fill up you usually get a message saying 326 miles till empty or whatever it is. When I got down to near 0 once my miles till empty after filling up were somewhere at least 30-40 miles higher then usual. That being said I deffently wouldn't trust the computer to get you an acurrate reading since going really low seemed to bug mine out.

I'm not entirely sure when it comes on... Seems like around 3 or 4 miles to "empty", though it could be related to ACTUAL remaining tank capacity as the last time I took it to under 5 miles to E it didn't come on, the entire fuel gauge turns a nice dark red. Like, the same color as the E marking on it. I don't recall how much I put in then, but if I take it that low again, I'll be sure to pay attention. I drive rather erratically, so it's hard to get a real good reading of how far a tank will stretch.

I have a question about that. My display read 4 miles to E yesterday right before I went to fill up. However the lettering did not turn red. Is it some other part of the display that is supposed to do that?

I'm pretty sure you have to have the display lit up to see the gauge turn red (i.e. when driving lights are on).

My computer has been very accurate for what that's worth. But yeah, running on low does not sit well with the fuel pumps.

Getting is all out for the 93 tune, lol.



http://home.comcast.net/~tribalwar/162.jpg

http://home.comcast.net/%7Etribalwar/0miles.jpg

http://home.comcast.net/~tribalwar/162.jpg

http://home.comcast.net/%7Etribalwar/162.jpg

Yours is by far the best reply! True, I shouldn't have been running around in NC in the dark without gas, but, sometimes.... Meanwhile, my computer appears to be pretty accurate, normaly when I fill it up and check the "Gallons Used" they are really, really close, unless I forget to reset that function PDQ when I get gas.

If you take your 16.226 gallons that you put in, compare it to my 15.44 gallons and to my approximate "14 Miles to Empty" and to my 2008 YTD Average MPG of 19.97 and make the calculations, we find that my system was less than a mile off to being out of gas. Of course, being stuck with a 3,700 pound car in really dark backroads NC, and flat, even with the gas station in site, would really be a drag. My wife has said she WILL NOT help me push!

Lol, yeah, I have been told, dont call me! But I usually fill up once the 50 miles to empty comes on for the most part.

The fuel guage shows 1 gallon (E) to 16 gallons (F).
The low fuel comes on at 10% left on the fuel guage.
15 gal x 10% = 1.5 gallons left when the warning light comes on
plus the 1 gallon that does not register on the guage.
So when the low fuel lamp comes on, you have 2.5 gallons left.
When my dashhawk shows 0% fuel left, it takes 15+ gallons
to make it read 100% full.

Not necessarily. It basis miles to empty from your avg mpg. Ive had the 50 miles to empty come on at 1/4 tank, and at 1/8 tank.

at 0 miles to empty you should have about 15 miles lift to go(aprox. 1 gal.) Dont worry about sucking dirt from the bottom of your tank because the pump always gets the fuel from the bottom.

The low fuel lamp in a non message center equipped stang.
Not the 50 miles to empty the message center displays.

16 gallons as per the owners manual.
Police interceptor S197s have an 18.5 gallon tank for some reason. ;)

But be aware that the fuel pump is no longer submerged
in fuel to help cool it.
I dont run mine with less than 6 gallons in the tank.
It helps to promote long fuel pump life as the pump is
still submerged in the fuel and receives proper cooling
unlike when the tank is almost empty.

When the gas prices were high, the repair places reported
an increase of in-tank fuel pumps because owners were running
their tanks lower before filling up again because of the prices.
The result was a sharp increase in in-tank fuel pump failures.
Fuel pump sales were at an all time high.

I hit 0 miles till empty, drove about 2 miles, filled up and it took 2L of fuel (about 0.75Gallons)

There were gas stations on my GPS that were not there in real life!!!!!

I just ran my tank down the other day. The fuel gauge turned red (the whole thing, icon and all) at 3 miles to E. The running/headlights have to be on for this to show up. I drive down to a bit under 0 miles to E (traffic sucks here), and put in 15.73 gallons. So, I think it quite possible that the gauge goes red at like, 1/2 gallon or so to go. Don't know for sure.

Mine goes red higher than that. I have had mine red at like 50 miles to empty.