Fuel gauge disagreement

[dlee1001]

When I turned my car off today, my fuel gauge read 5/12 bars (42%), which would be roughly 5 gallons, as the fuel tank holds 12.2 gallons. I have my OnStar RemoteLink app on my phone, and I make it a point to update it so I know exactly how much fuel I have left (in gallons) and how my tires are doing.

But the OnStar app on my phone, after having updated it right after turning my car off, read 6/12 bars (50%) and 6 gallons left. (If you have the app and look carefully at the fuel tank image, you'll see that the bars match that of the Sonic - 12 bars total.) Why the discrepancy, assuming that the data is collected from the most recent drive? Which one am I supposed to believe, the car's actual gauge or OnStar? Don't both readouts come from the same sensors?

 

[Yosemite Sam]

Welcome to the family dlee1001!! I have found that my fuel gauge is off 1 bar in actual fuel as yours is. When I fill up it's always 1 gallon less than what the gauge says I should be putting in.

:banana:

 

[dlee1001]

Welcome to the family dlee1001!! I have found that my fuel gauge is off 1 bar in actual fuel as yours is. When I fill up it's always 1 gallon less than what the gauge says I should be putting in.

:banana:

Well, at least I'm not the only one with an incorrectly reporting fuel gauge. I wonder if it's intentional? Or maybe a problem with how the fuel sensors were calibrated?

 

[Yosemite Sam]

I think it's more like underestimating. It will be at 1/2 tank and only take 5 gallons to fill.

 

[dlee1001]

I think it's more like underestimating. It will be at 1/2 tank and only take 5 gallons to fill.

When I filled up the tank all the way (when the pump clicked), the range said 409 miles, and now OnStar is saying I can go 197 miles with what I have now (5 or 6 out of 12 bars). The car was at about 615 miles at my most recent refueling, and now it's at 808 miles, all according to the app, which (correct me if I'm wrong) I believe polls its data from the car's sensors. That equates to 390 miles.

Something's not right here. I know all of this is not a huge deal, but it's the little things like these that are annoying.

 

[PlayCrackTheSky]

When I filled up the tank all the way (when the pump clicked), the range said 409 miles, and now OnStar is saying I can go 197 miles with what I have now (5 or 6 out of 12 bars). The car was at about 615 miles at my most recent refueling, and now it's at 808 miles, all according to the app, which (correct me if I'm wrong) I believe polls its data from the car's sensors. That equates to 390 miles.

Something's not right here. I know all of this is not a huge deal, but it's the little things like these that are annoying.

The miles to empty is just an estimate based on your previous mpg. Do not expect this to be accurate. It's just there to give you a general idea. It can change drastically depending on your driving style and conditions.

It definitely is not a realistic representation of your next tanks mileage. I would say more of a real time guesstimate that is constantly changing.

 

[Yosemite Sam]

It definitely is not a realistic representation of your next tanks mileage. I would say more of a real time guesstimate that is constantly changing.

This is why I don't use this "feature"!!!

:banana:

 

[dlee1001]

The miles to empty is just an estimate based on your previous mpg. Do not expect this to be accurate. It's just there to give you a general idea. It can change drastically depending on your driving style and conditions.

It definitely is not a realistic representation of your next tanks mileage. I would say more of a real time guesstimate that is constantly changing.

What is your opinion on the fuel tank readout discrepancy? Why do you think the fuel gauge itself and OnStar produce different readouts on the fuel level?

 

[JackGSonic]

The discrepancy is probably rounding. You might have 5.5 gallons, the car rounds it down to 5, Onstar rounds it up to 6. I have noticed that I have taken the tank to near empty, emptied the car gauge, low tank warning on, driven for 20 miles past that, and still filled the tank with only 11 gallons.

 

[Swordsmith]

The display gauge in my Sonic is consistently wrong; it reads about one gallon per bar. This means when I show zero bars, I still have as much as two point two gallons remaining in the tank. But it isn't consistent, I have on many occasions seen it go from one bar to two, from three bars to four, and so on. Sometimes it goes right back, but just as often I can go 20+ miles before it drops back down!

 

[SouthFLSonic]

When the Sonic reads empty you still have 2.2 gallons in the tank. Our tanks are 12.2 gallons but the gauges are set to only readout for 10 gallon tank if that makes any sense.

My car with gas light on, low fuel on the read out and no bars of gas can go for about 60 miles before it runs out(I have tired several times). Even my Ultragauge reads 2 gallons plus when my DIC reads empty.

 

[dlee1001]

The discrepancy is probably rounding. You might have 5.5 gallons, the car rounds it down to 5, Onstar rounds it up to 6. I have noticed that I have taken the tank to near empty, emptied the car gauge, low tank warning on, driven for 20 miles past that, and still filled the tank with only 11 gallons.

When the Sonic reads empty you still have 2.2 gallons in the tank. Our tanks are 12.2 gallons but the gauges are set to only readout for 10 gallon tank if that makes any sense.

My car with gas light on, low fuel on the read out and no bars of gas can go for about 60 miles before it runs out(I have tired several times). Even my Ultragauge reads 2 gallons plus when my DIC reads empty.

When I fueled up the car until the pump stopped by itself and I drove away, it took nearly 62 miles to drop to 11 bars (I was getting worried that there was something wrong with the fuel gauge). But after that the bars dropped more quickly.

Jack, I did notice that the OnStar app displays the fuel percentage in 5% increments and the gallons remaining is always a whole number. Perhaps it indeed is a rounding disagreement.

 

[laborsmith]

I have long used 0.9 per bar which works well for me. There is over a gallon in reserve, not sure it is as much as two, which to me accounts for the apparent discrepancy.


Laborsmith

 

[krakenredbeard]

Ya the miles to e changes based on your fuel economy. I filled up yesterday read out said 440 miles to e I live 12 miles from the gas station.

When I got home said I had 338 miles to e.

The gas gauge reads on 10 gallons not 12.2. I've road with zero bars for a full day trip to work which was 50 miles round trip and the next day still made it to the gas station which was 12 miles away and a hair under 12 gallons of gas in the vehicle.

Don't advise doing it but was broke and payday was the next day lol got lucky and made it.


Sent from my iPhone using Tapatalk

 

[mitdr774]

Most gauges are like this. It is like a reserve capacity. It is done to hopefully keep people from tuning thhe tank dry, since that is not good for the pump or engine. Every vehicle I have driven enough to have to fill up was like this. Its not a new development.