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Discussion Starter #1
I was under the impression our takes were 14.5 gallons, and when the gas light hit we had 2.5 gallons left. which means we used 12 gallons..

im i correct?

or is it 16.5 gallons, and when the light hits, we used 14 gallons?

im confused..

in any case.. my gas light hit the other night, because i wanted to see what kind of mileage iw as getting.
i went about.. 10 more miles, and got gas. I believe i was at 285 miles to that tank from the previous time i topped it off.

Well i filled this tank up, but it took 15.97 gallons?!?! wtf? even if it was a 16.5 gallon tank, i had a good 2 gallons left in there..

anyone care to enlighten me? +rep cuz this just screwed up my whole mpg calculation lol
 

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I'm pretty sure the tank is 16.5 gallons. Anyway, where did you hear about this 2.5 gallons left when the light comes on thing? I'm pretty sure the manual doesn't say this. That, however, is irrelevant.

The best way to calculate mileage is to fill up all the way until the pump shuts itself off. Let the pump do this by itself and don't pump again and again to try and get it fuller. Record mileage until you fill up again. Fill up until pump shuts itself off and do calculation based on volume the pump reads and your mileage. It really doesn't matter what the actual volume of the tank is if you use this method.
 

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The tank is 17.5 gallons.

Usually for me, the light comes on with about 2.5 gallons left, and I usually can get around 15 in there. The most I ever put in at anyone time was 16.

I don't think there is an "official" time/capacity when the light comes on.
 
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Discussion Starter #5
ooh i see. i have no idea where in the hell i saw 14.5 then. thats good to know tho, thank you

and Vandamage: ya thats what i did. Let the pump stop, then calculate the next time i got gas. i guess i was just confused on the whole light thing.
Actually, if you search the forum, i think there is a thread that a mod said there was 2.5 gallons left when the light comes on. But who knows for sure if thats right. like Squareback says, there is no "definite" answer to that i dont think.
But thanks!! i will have to fill up tonight, and see what kind of mileage im getting before i head to AZ tomorrow morning. lets see how good this girl does on long trips :)
 

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Discussion Starter #6
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Listen to me. When that car rolls into that dealership, and that tank is bone dry, I want you to be there with me when everyone says, "Collin and that
other guy, oh, they went further to the left of the slash than anyone ever dreamed!"

RICK: We did! We pulled it off! I can’t believe it! Where’s the needle?

COLLIN: Oh, it broke off, baby! Woo, hoo, hoo!
 

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Discussion Starter #8
Listen to me. When that car rolls into that dealership, and that tank is bone dry, I want you to be there with me when everyone says, "Collin and that
other guy, oh, they went further to the left of the slash than anyone ever dreamed!"

RICK: We did! We pulled it off! I can’t believe it! Where’s the needle?

COLLIN: Oh, it broke off, baby! Woo, hoo, hoo!
lmao! :lol: i would be the one to do that would I? haha just to see. god im lame. lol
 

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this just screwed up my whole mpg calculation.
??? This can't possibly screw up your MPG calculation because the size of the tank has nothing to do with it. How are you calculating your gas mileage using your tank size?
 

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yea...never use your tank size, that's not accurate.

Go until the light comes up, then take it there and fill her up. Keep your receipt (it has the number of gallons you just pumped in there). Then ride it out until the light comes on. Divide the number of gallons you filled it up with, with the number of miles you drive. If you fill up RIGHT when the light comes on and then get the mileage reading RIGHT when the light comes on you will get a more accurate reading because you are closer to using up all the gas you pumped in there when you filled it up (not the gas you pumped + whatever else was in there, or not even using all the gas you pumped).

The only way you can get an accurate reading by using the tank size is if you let it run completely out of gas...which i've done, ROFL! I was really bored and knew the tank size for my jetta. I had a couple gallons of 110 octane left and I reset my trip the time before when I filled it up to the rim. So I drove around with a gas can with a couple gallons of gas after the light came on and let it run out of gas. I then took the number of miles i had driven and divided them by my tank size...then I got out and emptied the 110 in there and changed the program over to 110 octane and had some fun on the way to the gas station :D HAHAHAH!!! it worked. Not only did i find out my EXACT gas mileage but I also found out EXACTLY how many miles I could drive when the gas light came on (which was 47 miles...that # stuck in my head because of thought of it everytime i had the gas light come on).
 

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yea...never use your tank size, that's not accurate.

Go until the light comes up, then take it there and fill her up. Keep your receipt (it has the number of gallons you just pumped in there). Then ride it out until the light comes on. Divide the number of gallons you filled it up with, with the number of miles you drive. If you fill up RIGHT when the light comes on and then get the mileage reading RIGHT when the light comes on you will get a more accurate reading because you are closer to using up all the gas you pumped in there when you filled it up (not the gas you pumped + whatever else was in there, or not even using all the gas you pumped).

The only way you can get an accurate reading by using the tank size is if you let it run completely out of gas...which i've done, ROFL! I was really bored and knew the tank size for my jetta. I had a couple gallons of 110 octane left and I reset my trip the time before when I filled it up to the rim. So I drove around with a gas can with a couple gallons of gas after the light came on and let it run out of gas. I then took the number of miles i had driven and divided them by my tank size...then I got out and emptied the 110 in there and changed the program over to 110 octane and had some fun on the way to the gas station :D HAHAHAH!!! it worked. Not only did i find out my EXACT gas mileage but I also found out EXACTLY how many miles I could drive when the gas light came on (which was 47 miles...that # stuck in my head because of thought of it everytime i had the gas light come on).
The more accurate and safe way is to fill up completely, then reset your tripometer. Next time you fill up just divide the amount of miles by gallons. If you fill up right when the light comes on and you know your tank capacity (back of the owner's manual), you can also figure out how many gallons is left in the tank when the light comes on, and if you multiply that by your mpg you'll know how many miles 'til empty.

That way you won't end up stranded like an asshole.
 

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In the first place, why would you strecth your fuel capacity till the gas light comes on :suspiciou Doing this repeatedly is not good for your fuel system and can cause the CEL to come on. Try to always keep it at 1/4 full.
 

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Basically what I was saying. I was just pointing out to try and fill up right when the light comes on and get the reading at the same time you filled up previously so you burn the same amount of gas you filled up with. Either way works perfect.


And I was just having fun with the going until the car runs out. Me and a friend were bored one weekday night and decided to do it without math, lol and I had some race gas left over that I wasn't going to burn for a while anyways. Jollibee's way to find out how many miles you can go when the light comes on is cheaper and less time consuming. Because to be safe I drove around neighborhoods until it ran out of gas, and honestly it's never good to run your car that low when you have miles on it. If you happen to get some not so clean gas, the stuff settles at the bottom and when you have a decent amount of miles on your car and you run it bone dry then it sucked up whatever was settled at the bottom of the tank. The best rule of thumb is to not let your gas needle go below an 1/8th of a tank. Personally I rarely let mine go past half a tank because I'm a smoker and if I'm stopping to get cigarettes then I might as well get gas too. But that's a whole different topic.
 

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In the first place, why would you strecth your fuel capacity till the gas light comes on :suspiciou Doing this repeatedly is not good for your fuel system and can cause the CEL to come on. Try to always keep it at 1/4 full.
Please explain how driving to the light damages the fuel system.
 

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Please explain how driving to the light damages the fuel system.
If you let your fuel tank run dry, you run into a whole set of problems from siezed fuel pump, damage injectors, damage injector manifolds. There is also another thing to think about, all gas tanks have curds in them....there are screens, restrictors and filters to keep the curds out of the smaller parts of the fuel system, but do you really want to push the odds. Remember the fuel in your tank runs the engine which is obvious, it also helps keep the fuel pump from overheating. If you let your fuel run low, there will not be enough fuel in the tank to cool the fuel pump. Remember, the damage to your car may not happen right away...heck it may not even happen after several times of running your tank low but eventually your fuel system will fail
 

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If you let your fuel tank run dry, you run into a whole set of problems from siezed fuel pump, damage injectors, damage injector manifolds. There is also another thing to think about, all gas tanks have curds in them....there are screens, restrictors and filters to keep the curds out of the smaller parts of the fuel system, but do you really want to push the odds. Remember the fuel in your tank runs the engine which is obvious, it also helps keep the fuel pump from overheating. If you let your fuel run low, there will not be enough fuel in the tank to cool the fuel pump. Remember, the damage to your car may not happen right away...heck it may not even happen after several times of running your tank low but eventually your fuel system will fail
I'm definitely with you on running it dry, but waiting 'til the light comes on to fill up is a non-issue. There's still over 3 gallons at that point.
 

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I'm definitely with you on running it dry, but waiting 'til the light comes on to fill up is a non-issue. There's still over 3 gallons at that point.
True, but maybe being OCD about this type of stuff with my vehicles I don't like doing it. I purchase vehicles not just as transportation but because I love everything about them and what you can do with them. So I take VERY good care of my car. I'm sure running until the light comes on is not a bad idea, but if you wait for the light chances are (unless you are one lucky SOB) you aren't right next to a gas station. So that 3 gallons can easily become 2 or 1 gallons left.

The only time I run my car below a little over an 1/8th of a tank is when I take it to the track. Before I do that part of my track prep is to run Chevron Techron fuel system cleaner to clean any deposits that maybe work themselves past the screens and the system...don't use the entire bottle because using this stuff too often can cause...well stuff to be eaten up. So use half the bottle before and then half after. For me the same applies to when I allow my car to go below just over an 1/8th of a tank. Although like I said it rarely gets that low because I am at gas stations a lot because of a dirty smoking habit i have and a mountain dew addiction :X haha.

EDIT: It's hard to really debate this. I guess the BEST answer is IF your light comes on then get to the nearest gas station ASAP and unless you keep track of filling up (i have a small flip notepad I write stuff like that down in) then it's also not good to keep filling up without letting it get fairly low because there will still be old gas left in there (turns into bad gas; and i know that the car turns and the gas gets sloshed around and "mixes" but it's not shaken and stirred, so there will still be old gas) which can hinder performance and gas mileage.
 

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In the first place, why would you strecth your fuel capacity till the gas light comes on :suspiciou Doing this repeatedly is not good for your fuel system and can cause the CEL to come on. Try to always keep it at 1/4 full.
You stretch your available fuel because the more fuel you use from a full tank the more miles you drive and, hence, more accurate MPG calculations. I don't recommend running the tank dry, though. Running it to the light will be OK.
 

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Discussion Starter #19
word. getting 22-26mpg
 

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There's no point in driving until the light comes on to check the fuel economy because you're still not at the bottom of the tank. I usually just drive to the last 1/4 of the tank and then calculate based on how much it takes to fill back up.
 
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