Fuel gauge behaving badly

[dlee1001]

This has been an intermittent problem over the past 11 months I've had my Sonic (1.8L 6AT), but it's been recurring more frequently, since yesterday. The car has about 7200 miles on it.

After driving about 20 miles somewhere with my fuel gauge showing, let's say, 11 bars, and I arrive at my destination and turn my car off, do my business, and come back to my car and turn it on again, I notice that the fuel gauge now shows 10 bars instead of 11. Every time this happens, I know I could have gone further with that 11th bar. And no, I'm not seeing things; the fuel gauge clearly showed 11 bars before I turned my car off, and after turning it back on the fuel gauge had dropped one bar.

Sometimes the bar comes back for a few miles, and then it disappears for good until the next fill-up; other times, it disappears and never comes back until the next fill-up. I can go anywhere between 23 to 38 miles on one bar.

As mentioned in the beginning of this post, this started happening more often starting yesterday. Driving any distance longer than 20 miles, turning the car off, and turning it back on will cause one bar to drop on the fuel gauge. It doesn't matter how many bars there were before I turned the car off; it can show 7 bars before and show 6 bars after, or 5 bars before and 4 bars after, etc. The car is almost always parked on level ground.

I have no idea if this is normal or not. What is causing this kind of behavior?

 

[hammrdwn510]

I came here looking for a naughty fuel gauge....

I've been skeptical about the same thing in some of my previous vehicles, but never really thought about it

Maybe an ultra gauge for better fuel level/consumption readings?
Possibly sensor/float in fuel tank is going bad?

 

[Chevrolet Customer Care]

This has been an intermittent problem over the past 11 months I've had my Sonic (1.8L 6AT), but it's been recurring more frequently, since yesterday. The car has about 7200 miles on it.

After driving about 20 miles somewhere with my fuel gauge showing, let's say, 11 bars, and I arrive at my destination and turn my car off, do my business, and come back to my car and turn it on again, I notice that the fuel gauge now shows 10 bars instead of 11. Every time this happens, I know I could have gone further with that 11th bar. And no, I'm not seeing things; the fuel gauge clearly showed 11 bars before I turned my car off, and after turning it back on the fuel gauge had dropped one bar.

Sometimes the bar comes back for a few miles, and then it disappears for good until the next fill-up; other times, it disappears and never comes back until the next fill-up. I can go anywhere between 23 to 38 miles on one bar.

As mentioned in the beginning of this post, this started happening more often starting yesterday. Driving any distance longer than 20 miles, turning the car off, and turning it back on will cause one bar to drop on the fuel gauge. It doesn't matter how many bars there were before I turned the car off; it can show 7 bars before and show 6 bars after, or 5 bars before and 4 bars after, etc. The car is almost always parked on level ground.

I have no idea if this is normal or not. What is causing this kind of behavior?

Hello dlee1001,

We're sorry to learn of this issue you're experiencing with the fuel gauge in your Sonic. We realize an intermittent issue can be rather challenging to pinpoint, nonetheless, we encourage you to take your vehicle into a certified GM dealership the moment this occurs more frequently. As you may know, we are here if additional assistance is needed.

All the best,

Jasmine F
Chevrolet Customer Care

 

[SonicBoy24]

This has been an intermittent problem over the past 11 months I've had my Sonic (1.8L 6AT), but it's been recurring more frequently, since yesterday. The car has about 7200 miles on it.

After driving about 20 miles somewhere with my fuel gauge showing, let's say, 11 bars, and I arrive at my destination and turn my car off, do my business, and come back to my car and turn it on again, I notice that the fuel gauge now shows 10 bars instead of 11. Every time this happens, I know I could have gone further with that 11th bar. And no, I'm not seeing things; the fuel gauge clearly showed 11 bars before I turned my car off, and after turning it back on the fuel gauge had dropped one bar.

Sometimes the bar comes back for a few miles, and then it disappears for good until the next fill-up; other times, it disappears and never comes back until the next fill-up. I can go anywhere between 23 to 38 miles on one bar.

As mentioned in the beginning of this post, this started happening more often starting yesterday. Driving any distance longer than 20 miles, turning the car off, and turning it back on will cause one bar to drop on the fuel gauge. It doesn't matter how many bars there were before I turned the car off; it can show 7 bars before and show 6 bars after, or 5 bars before and 4 bars after, etc. The car is almost always parked on level ground.

I have no idea if this is normal or not. What is causing this kind of behavior?

You mentioned that you can go between 23 to 38 miles per bar, and that the problem only happens when driving more than 20 miles.

It sounds like to me, and something that I have noticed. That the computer is trying to determine and measure the fuel in the tank and therefore changes the reading.

From my personal experience:
Usually after a fill up, I lose the first bar between 44 and 55 miles of driving. But yesterday I filled up, drove 70 miles at 45-50 miles an hour, and I didnt lose the first bar until 67 miles.

I think the computer uses your average fuel mileage, rpm, and other factors with the tank sensor for fuel display.

 

[dlee1001]

You mentioned that you can go between 23 to 38 miles per bar, and that the problem only happens when driving more than 20 miles.

It sounds like to me, and something that I have noticed. That the computer is trying to determine and measure the fuel in the tank and therefore changes the reading.

From my personal experience:
Usually after a fill up, I lose the first bar between 44 and 55 miles of driving. But yesterday I filled up, drove 70 miles at 45-50 miles an hour, and I didnt lose the first bar until 67 miles.

I think the computer uses your average fuel mileage, rpm, and other factors with the tank sensor for fuel display.

Among other things, could it also be due to the fact that the fuel gauge was "ready" to drop one bar, and the fuel used to turn the car back on was enough to drop one bar? Or that turning the car off and back on again resets the computer somewhat?

 

[beaslbob]

FWIW sounds to me like how a digital fuel gauge (or any digital gauge) would work. Seems Like it gets down to almost one bar down then can kinda "gets confused" until it is definitely one bar down.

that's a lot better then our 2006 envoy where it went down to empty tank from full all the sudden. that was a fuel sensor/fuel pump problem.

just my .02

 

[VaBumbleBee]

I always tell the gf I get paid to notice things, I would never have even noticed this and fail to see the problem? Enjoy your Sonic, dude!!! I do mine, badass little car.

 

[Hawkdsl]

I think its normal.. Mine is just 1000 miles old now, but the first week I had it, the fuel gauge took forever to start dropping down... now.. heh.. it must have gained weight.

8 gallons to fill up is like filling up a motorcycle. Cracks me up for a car.