Actual amount of gas left in tank vs. trip computer warning?

[whiteGT]

With my 2000 GT when the low light came on i knew there were two gallons left in the tank.

With my 2012 GT when the computer warns 50 miles to Empty and displays average MPG as 22 it computes to just over two gallons left in the tank. When i get to 25 miles to empty and the displayed average MPG is 22 thinking i have one gallon left i stop for gas and it takes 13.5 gallons to fill it up. Manual states 16 gallon tank, based upon the computer i had one gallon left leaving an apparent fudge factor of 1.5 gallons. It would seem if i went the additional 25 miles the computer would indicate the tank is empty and my guess is it would take 14.5 gallons to fill the tank??? The gas gauge does not quite read empty.

Anyone drive past the computer warning when it predicts you will run out of gas and find you get about 1.5 times the last average MPG of miles before you really run out of gas (in other words there is a 1.5 gallon fudge factor)? Is the gas gauge needle past "E" when you run out of gas?

 

[01bluesnake]

With my 2000 GT when the low light came on i knew there were two gallons left in the tank.

With my 2012 GT when the computer warns 50 miles to Empty and displays average MPG as 22 it computes to just over two gallons left in the tank. When i get to 25 miles to empty and the displayed average MPG is 22 thinking i have one gallon left i stop for gas and it takes 13.5 gallons to fill it up. Manual states 16 gallon tank, based upon the computer i had one gallon left leaving an apparent fudge factor of 1.5 gallons. It would seem if i went the additional 25 miles the computer would indicate the tank is empty and my guess is it would take 14.5 gallons to fill the tank??? The gas gauge does not quite read empty.

Anyone drive past the computer warning when it predicts you will run out of gas and find you get about 1.5 times the last average MPG of miles before you really run out of gas (in other words there is a 1.5 gallon fudge factor)? Is the gas gauge needle past "E" when you run out of gas?

For one, not sure why you are worried about running the car down to E? also highlighted some key words. The system just computes an average MPG over a certain amount of time, and not instant as you are driving. second, you will never stay driving a constant speed, and the system is only for reference of when it expects you to run out. They will also always give a little bit of wiggle room for people like you who run the cars down to close to empty so you dont stall while turning, stopping or accelerating and cause an accident then try to sue Ford because "you werent on empty yet, so it shouldnt of died out."

 

[megameGT500]

I have a terrible habit of driving until the 50 mile warning signal. I have heard many times that it is not good for the fuel pump and in fact I had a 97 Camaro that the fuel pump went bad in it right when the warranty ran out. I try very hard to fill up at 1/2 or a little less because of the fuel pump but I have filled up when I the computer reads a little more than more than 15 miles and it takes 13.5 to 13 gallons to fill up. Hopefully I can break this bad habit.

 

[Torch10th]

The main issue with the running the tank until E is/was fuel contamination. Sediments tend to drop to the bottom of the tank, so you're pulling the "sludge" of the tank.

With modern tank design, fuel pickups and filling station practices, this isn't the issue that it used to be.

01bluesnake is exactly right though. Ford has to put in some wiggle room, because people are in fact idiots and WILL run their car out of fuel trying to take little johnny to soccer practice, day care, chuck-e-cheeses and grandma's house on a gallon of fuel.

Now, you can't always be on your game, but I start thinking about fueling once I hit 1/4 tank. That gives me plenty of time (several days usually) to get fuel and I'm not left wondering why the computer isn't pin-point accurate.

I watch the trip meter and I usually end up getting fuel around 280 miles.

 

[BryanW]

I keep all my receipts and have a notebook in the car to keep track of mpg and miles of the car
One time I ran it down to 1 mile left, I assumed all cars have a reserve in the tank that the gauge will not calc for. My diesel it was 5 gallons...

So here's what I came up with 6-11-11. 324 miles on tank 1 mile til empty...
14.708 gallons when it clicked...
Now that also brings up another point, dealer told me let the pump click and that was full, don't try and put more in it.,, or it would flow out and get on the paint. With that said. Thats how I used to fill up. Now I add more to the tank and yet have spilled any fuel.
Btw fuel was 3.90/ gallon last June Saturday it was 3.19 a gallon

 

[BryanW]

I forgot to mention, I hand calculate my mpg and by my calc I get 1/2- 3/4 more mpg. I always write down car says 21.3 mpg and hand calc would have been 22.035 mpg with above post.

 

[01bluesnake]

I keep all my receipts and have a notebook in the car to keep track of mpg and miles of the car
One time I ran it down to 1 mile left, I assumed all cars have a reserve in the tank that the gauge will not calc for. My diesel it was 5 gallons...

So here's what I came up with 6-11-11. 324 miles on tank 1 mile til empty...
14.708 gallons when it clicked...
Now that also brings up another point, dealer told me let the pump click and that was full, don't try and put more in it.,, or it would flow out and get on the paint. With that said. Thats how I used to fill up. Now I add more to the tank and yet have spilled any fuel.
Btw fuel was 3.90/ gallon last June Saturday it was 3.19 a gallon

The problem with topping after it stops is not fuel coming out of the neck, its flooding the charcoal canister with raw fuel amounts its not meant to handle and causing the Evap system to malfunction and not do its job properly which is to deal with fuel vapors. Dont be surprised if you start having evap system concerns later down the road from over saturating the charcoal canister with raw fuel. At the dealer we usually(up to dealer) warranty the first one a customer ruins, after that it will go into customer paying the tab for their ignorance of how something functions and lack of care to maintain that. Just a FYI

It kind of surprises me how some people are so meticulous amount their cars or fuel mileage but care so little to understand why they shouldn't do some things they do or learn how something actually functions, but instead have the "well thats what the internet said or "thats what i always did so its fine" mentality.

 

[01bluesnake]

..

 

[whiteGT]

BryanW- thank you for actually answering the posted question! It seems the fuel system will hold 16 gallons, but the low fuel warnings and gauge reading "E" are calibrated to be measuring the ~ 14.7 gallons of gas Ford intended to be the normal operational volumes, while the last ~ 1.3 gallons Ford considers to be the reserve amount and desires the customer have filled up before getting this low for obvious reasons.

01bluesnake- while you may have many interesting points to add to postings, please don't do it in a condescending manner. For example not evening knowing me you stereotype me as someone who will run out of gas and what ever other nonsense you were insinuating. Putting other people down to make yourself look good just shows a lack of maturity , a lack of etiquette and generally an inferiority complex. Did you ever consider some day you may have an emergency where you have to take someone to the hospital and if your car was on "E" but you know you have 1.3 gallons left and the hospital is 10 miles away there is no need to stop for gas which timewise could be the difference between life and death? Did you ever consider that fewer times at the pump is less time wasted there so more time can be spent living life? Fewer times starting and stopping the engine means longer engine life????

 

[01bluesnake]

01bluesnake- while you may have many interesting points to add to postings, please don't do it in a condescending manner. For example not evening knowing me you stereotype me as someone who will run out of gas and what ever other nonsense you were insinuating. Putting other people down to make yourself look good just shows a lack of maturity , a lack of etiquette and generally an inferiority complex. Did you ever consider some day you may have an emergency where you have to take someone to the hospital and if your car was on "E" but you know you have 1.3 gallons left and the hospital is 10 miles away there is no need to stop for gas which timewise could be the difference between life and death? Did you ever consider that fewer times at the pump is less time wasted there so more time can be spent living life? Fewer times starting and stopping the engine means longer engine life????

I dont need to stereotype you as someone who runs their cars down to E, you did for yourself in your first post. You listed you would run your previous mustang down till the light came on cause you knew you had 2 gallons left, now with this car you take it down to where you assumed you had only 1 gallon left and found that the car still gives you more to push farther. I would not need to worry about not getting to a hospital because i always fill up before it gets below a 1/4 in any of my cars, and if thats something you worry about maybe you need to change your fill up habit. Really, are you really bringing up life vs time at the gas pump?? :nonono: Running your car down to E vs filling up at a 1/4 is not going to end your cars life or cause engine failure. Yes, start ups on a motor are the hardest, but i think you have taken that to a little extreme if you feel stopping for gas before you run out is better.

 

[MikeLTDLX]

So far the furthest I have been able to go without a refill is 245 miles. This is combined city and highway driving with an MT-6 car with 3.31s. It usually takes about 13.5 gallons when I fill it. I fill it when it tells me I have 25 miles left until E. Best "average" MPG on the computer has been 17.1. I don't pound on it non-stop, but I do use my right foot. Mileage has not been stellar, but not dismal either. I don't know how someone is getting 300+ miles out of tank though, unless on cruise control on the highway at 65 mph.

Mike

 

[maniak87]

BryanW- thank you for actually answering the posted question! It seems the fuel system will hold 16 gallons, but the low fuel warnings and gauge reading "E" are calibrated to be measuring the ~ 14.7 gallons of gas Ford intended to be the normal operational volumes, while the last ~ 1.3 gallons Ford considers to be the reserve amount and desires the customer have filled up before getting this low for obvious reasons.

01bluesnake- while you may have many interesting points to add to postings, please don't do it in a condescending manner. For example not evening knowing me you stereotype me as someone who will run out of gas and what ever other nonsense you were insinuating. Putting other people down to make yourself look good just shows a lack of maturity , a lack of etiquette and generally an inferiority complex. Did you ever consider some day you may have an emergency where you have to take someone to the hospital and if your car was on "E" but you know you have 1.3 gallons left and the hospital is 10 miles away there is no need to stop for gas which timewise could be the difference between life and death? Did you ever consider that fewer times at the pump is less time wasted there so more time can be spent living life? Fewer times starting and stopping the engine means longer engine life????

all bluesnake did was provide you with TRUE facts. if you think he was being condescending you should probably thicken up your skin if your gonna post up around here. fact of the matter is, you shouldnt wait till the last second to fill up your tank. you actually think your wasting the time in your life pumping gas?? that might all catch up to you once your car is in the shop for a week waiting on parts for new evap parts and a fuel pump.

btw, i know drew personally he is an awesome guy and he is a ASE certified mechanic/senior ford tech. he isnt just spewing out some bull shit from things that he has read around forums, he sees it first hand...

 

[01bluesnake]

Thanks Zach, also on that note, im a senior Ford tech as well which i know you are aware of, just not others. BryanW noted he topped off his tank after it shuts off, the Op didnt do that, at least i hope not.
Even with all the pump station filters, and new technology, you will always get sediment in the tank and running low will still take its effect on the pump eventually. The less fuel in the tank will also create more hot duty cycles from the pump.

 

[maniak87]

Thanks Zach, also on that note, im a senior Ford tech as well which i know you are aware of, just not others. BryanW noted he topped off his tank after it shuts off, the Op didnt do that, at least i hope not.
Even with all the pump station filters, and new technology, you will always get sediment in the tank and running low will still take its effect on the pump eventually. The less fuel in the tank will also create more hot duty cycles from the pump.

wont the fuel filter take care of the sediment though? (prematurely wearing out the filter if you habitually run it low though)

 

[01bluesnake]

wont the fuel filter take care of the sediment though? (prematurely wearing out the filter if you habitually run it low though)

The pumps all run a pre filter which stops bigger particles, then you have the aft filter from the pump which stops any smaller items from getting to the injectors. The smaller particles still go through the pump pre filter though.

 

[maniak87]

The pumps all run a pre filter which stops bigger particles, then you have the aft filter from the pump which stops any smaller items from getting to the injectors. The smaller particles still go through the pump pre filter though.

right, the "sock" on the end of the pump.

 

[01bluesnake]

yep, that would be it.

Let me also note that since there are no gas caps on these cars, dirt and any road debris sits on the flapper valve which gets introduced into the tank every time gas is added.

 

[D.T.R]

yep, that would be it.

Let me also note that since there are no gas caps on these cars, dirt and any road debris sits on the flapper valve which gets introduced into the tank every time gas is added.

I thought that was weird (not having a cap) ... but at the same time pretty nice to just "click" the door and begin fueling

 

[01bluesnake]

Ya, it is nice feature not having to undo a cap or possibly forgetting to put it back on. It also got rid of a chance the gas cap would let gas vapors vent to the atmosphere when bad, but so far we have seen a few sealing concerns with the flapper valves and evap leaks at the necks, so not sure how much better control this system has vs gas cap setup, it does take the human error factor out from cap problems though.

 

[BryanW]

Thanks Zach, also on that note, im a senior Ford tech as well which i know you are aware of, just not others. BryanW noted he topped off his tank after it shuts off, the Op didnt do that, at least i hope not.
Even with all the pump station filters, and new technology, you will always get sediment in the tank and running low will still take its effect on the pump eventually. The less fuel in the tank will also create more hot duty cycles from the pump.

Hey thanks for the advice on me filling it past full, honestly i didnt think about it.
Well, when i go and fill the car up and the pump clicks saying that its full, all ive been doing is give it one more squeeze and it clicks again. Usually 1/4 of a gallon is added. Is this enough to cause problems with the charcoal cannister? Its not like im trying to add 5 more gallons and get it to spew out the top.

So far the furthest I have been able to go without a refill is 245 miles. This is combined city and highway driving with an MT-6 car with 3.31s. It usually takes about 13.5 gallons when I fill it. I fill it when it tells me I have 25 miles left until E. Best "average" MPG on the computer has been 17.1. I don't pound on it non-stop, but I do use my right foot. Mileage has not been stellar, but not dismal either. I don't know how someone is getting 300+ miles out of tank though, unless on cruise control on the highway at 65 mph.

Mike

I drive 15 miles one way to work, 15 miles back. 2 miles each way is city driving, stop light to stop light. Then construction and sometimes good easy days to and from. I fill up when its convenient, all my mpg is around 21. Here are the miles ive driven between fill ups.
305 291 223 324 215 266 247 275 231 253 244 246 232 234 254 290 334 252
Still waiting for a road trip and get 29-30mpg out of it, with the cruise set at 60mph and reset the trip, the mileage usually stays at 30-31 on flat ground. car is a auto with 3.15 gears