Fuel Gauge Problem - Incorrect "Miles to Empty" Reading

[Farmundeh]

I first noticed several weeks ago that the gas gauge/low fuel indicator in my car wasn't very reliable and consistent. There were a few occasions where it would suddenly drop from 1/4 tank or less to E, with the "__ miles to empty" dropping super fast. I chalked it up to the computer possibly getting confused by my gas-guzzling city driving around NYC with intermittent highway driving, along with my unpredictable use of the paddle shifters.

However, after what happened to me yesterday I'm convinced that there is a legitimate problem with my car. I was driving back from Northern VA and had filled up in MD. I was cruising along comfortably on the Jersey Turnpike getting about 23-24 mpg. After about 190-ish miles, with the gas gauge just below half a tank and it reading "138 miles to empty", the gauge dropped completely to "E" and the low fuel indicator/warning light suddenly went off informing me that i have "5 miles to empty". After nearly wetting myself, I realized that fortunately I was close to a service station and managed to get my car to a Sunoco. I intentionally put in as much gas as I could to see whether the tank was truly empty. Sure enough I was only able to pump a shade over 9 gallons. Once I restarted the car, all seemed normal.

Has this or anything remotely similar happened to anyone else? Any ideas as to what it might be? Also, assuming it's just a sensor issue and I know there actually is more gas in the tank than what the system is telling me, am I fine to continue driving? Or will the car think the tank is actually empty and cause the engine to shut off?

Apologies if this has already been discussed, I tried searching and didn't come across anything. If there is already a thread on this can someone please direct me to it? Thank you.

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[Farmundeh]

*bump* anyone?

 

[EngineerDave]

I have not had that issue. I've gone through 2 tanks of fuel, and the miles to empty has been fairly accurate (aside from dropping 5 or so miles if I'm ragging it.) What sort of station are you using to fill up at normally? Have you visited any "cheap" stations or groceries with pumps? It SOUNDS like you might have some debris that's blocking a sensor, which would also lead to the rough running when you get to 1/4th a tank. Also be mindful of the Eth rating for the gas when you fill up. You can try and run some Chevron with Techron through it for a tank or two (91/93 oct.) and see if that sorts it out, else you might need a trip to a dealer.

 

[dgc333]

Sounds like the sender in the tank has an intermittent connection.

 

[JimmyTwoTimes]

I first noticed several weeks ago that the gas gauge/low fuel indicator in my car wasn't very reliable and consistent. There were a few occasions where it would suddenly drop from 1/4 tank or less to E, with the "__ miles to empty" dropping super fast. I chalked it up to the computer possibly getting confused by my gas-guzzling city driving around NYC with intermittent highway driving, along with my unpredictable use of the paddle shifters.

However, after what happened to me yesterday I'm convinced that there is a legitimate problem with my car. I was driving back from Northern VA and had filled up in MD. I was cruising along comfortably on the Jersey Turnpike getting about 23-24 mpg. After about 190-ish miles, with the gas gauge just below half a tank and it reading "138 miles to empty", the gauge dropped completely to "E" and the low fuel indicator/warning light suddenly went off informing me that i have "5 miles to empty". After nearly wetting myself, I realized that fortunately I was close to a service station and managed to get my car to a Sunoco. I intentionally put in as much gas as I could to see whether the tank was truly empty. Sure enough I was only able to pump a shade over 9 gallons. Once I restarted the car, all seemed normal.

Has this or anything remotely similar happened to anyone else? Any ideas as to what it might be? Also, assuming it's just a sensor issue and I know there actually is more gas in the tank than what the system is telling me, am I fine to continue driving? Or will the car think the tank is actually empty and cause the engine to shut off?

Apologies if this has already been discussed, I tried searching and didn't come across anything. If there is already a thread on this can someone please direct me to it? Thank you.

A number of people have complained that the "low fuel" warning doesn't come on until you're almost entirely out of fuel (like, less than a half-gallon left), but what you described is definitely a sensor issue -- probably with the float inside the tank.

 

[Farmundeh]

I have not had that issue. I've gone through 2 tanks of fuel, and the miles to empty has been fairly accurate (aside from dropping 5 or so miles if I'm ragging it.) What sort of station are you using to fill up at normally? Have you visited any "cheap" stations or groceries with pumps? It SOUNDS like you might have some debris that's blocking a sensor, which would also lead to the rough running when you get to 1/4th a tank. Also be mindful of the Eth rating for the gas when you fill up. You can try and run some Chevron with Techron through it for a tank or two (91/93 oct.) and see if that sorts it out, else you might need a trip to a dealer.

Funny you mention this. I'm actually very particular about where I pump gas. I won't go to discount gas stations and off the top of my head, i believe i went to nothing but Sunoco stations for the last 2 weeks (in various locations between NYC and Northern VA). And i only pump 93. I always thought Sunoco gas was decent, anyone disagree?

Sounds like the sender in the tank has an intermittent connection.

A number of people have complained that the "low fuel" warning doesn't come on until you're almost entirely out of fuel (like, less than a half-gallon left), but what you described is definitely a sensor issue -- probably with the float inside the tank.

I figured its some sort of a sensor issue in the tank. My concen is that it'll be one of those cat and mouse situations when i take it in for service, with the dealership saying "we cant get it to happen so we're not sure what the exact problem is, etc, etc...":frusty:

 

[EngineerDave]

I've never actually used Sunco, so I don't know. I mostly stick to Chevron and BP stations, I've always had very consistent gas from them regardless where I've gotten them from. Here in Kentucky Suncos always "look" questionable, they typically look about as inviting as a swifty lol. Yours might be better maintained and cared for though! If you don't want to go through the hassle of the dealership right away you could always try and disconnect the battery for a bit to reset your ECU (the good ol' have you tried turning it off and on again?) to see if that fixes it. If that still doesn't work a dealership visit might be in order.

 

[dgc333]

Just a couple of points of fact to keep in mind;

Gasoline is a commodity that is sold back and forth between oil companies. What this means is gas refined by Mobil may be in distribution tanks owned by Shell.

Not every brand in a geographical area has a distribution center, there is usually only a couple. So Sunoco in your area may come from distribution tanks owned by Citgo and in another area from tanks owned by Mobil.

The only thing unique from brand to brand is the additive package that is dumped into the tanker truck at the time it is filled and then the only real difference is top tier put in more.

IMHO, you are better off going to the local Speedy Mart that is very busy and is getting fuel every couple of days than a name brand that only gets fuel once a month.

 

[Farmundeh]

Interesting points gentlemen. Thank you for the feedback. I guess one of the benefits of living in a such a densely populated area is that more than likely none of the gas stations i'm using will be sitting on 'old' gas. I'll probably take her in next week to have it looked at, it's snowing again this weekend so i figured it could wait.

 

[Old 5 Oh]

My car consistently gives me Low Fuel at about 50 miles to empty on the computer.

Unfortunately, that's really only about 30 miles to empty, as the last 50 miles roll off at about a twice-normal rate. (Same thing with my MKZ, so maybe Ford thinks this is a "feature.")

The other weirdness is that MPG by the computer is consistently 1.5 mpg better than manual calculation of miles divided by gallons. Every tank, every time, 1.5 mpg different.

Strange.

 

[Gurion4887]

Hi I'm late to this thread but I just wanted to mention I experienced the exact same issue with my car today. If you see this, did you resolve the issue?

 

[Farmundeh]

My car consistently gives me Low Fuel at about 50 miles to empty on the computer.

Unfortunately, that's really only about 30 miles to empty, as the last 50 miles roll off at about a twice-normal rate. (Same thing with my MKZ, so maybe Ford thinks this is a "feature.")

The other weirdness is that MPG by the computer is consistently 1.5 mpg better than manual calculation of miles divided by gallons. Every tank, every time, 1.5 mpg different.

Strange.

Very strange. I definitely found my S197 to be far more accurate in this regard.

Hi I'm late to this thread but I just wanted to mention I experienced the exact same issue with my car today. If you see this, did you resolve the issue?

It hasn't been resolved, simply because I haven't had the chance to take my car in for service. But i should note that since then i've driven my car back down to Northern VA once and even up to Toronto (10 hour road trip). I played it safe and made sure to stop for gas regularly. The longest i'd go without a gas stop was two and a half hours. No issues. Even with city driving, i've pushed the car to as low as 20 miles left till empty and no unusual behavior. I'm really hoping that it was just a fluke or a case of bad fuel, but eventually I want to take it in to get looked at. One dealership I spoke with said the fuel tank will likely have to get dropped in order for them to replace one of the sensors. Sounds pretty intensive.

 

[DarkHorse850]

Quick related question, when you fill up what are your "Miles to Empty" showing as? Mine usually states about 230.

 

[Farmundeh]

Quick related question, when you fill up what are your "Miles to Empty" showing as? Mine usually states about 230.

it depends on what your MPG reading is at the time I believe. Mine has ranged from low 200s to 300+

 

[dgc333]

Quick related question, when you fill up what are your "Miles to Empty" showing as? Mine usually states about 230.

405 to 420, the low fuel light comes when there is about 380 miles on the trip and the miles to empty is between 35 and 40.

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