Fuel Gauge not resetting to full

[phobos512]

So I got gas this morning before heading out for adventure and home and didn't pay attention to the fuel gauge.

After our first destination I noticed the gauge was below the first quarter in only 30 miles. Checked and the digital gauges said 30.1 MPG so something was up. Pulled into a gas station near second destination and tanked up, and found the fuel gauge is not returning to full. It just returns to where it was before the vehicle was shut off. Anyone experience this before?

No idiot lights have come on yet but I don't have my OFT with me to see if it has popped any codes. Also going out of town tomorrow for business so won't be able to get it in to the dealer until next week at the earliest. Thanks!

[N1rve]

Sounds like that fuel pump plunger like mechanism is broken. Take it to the dealer and have them check it out.

[slowstang]

Pull the battery to reboot the car first, mine did the same thing.

[Gords_zenith]

It will reset itself. Just keep driving and fill up normally. I had this when I first got my car in July 2012.

[phobos512]

Thanks all. I'm a week shy of a year of ownership and I've never seen it do this before. I found a page after I posted this thread about folks having seen this when filling up with just a little gas; I had filled up at ~80 miles; I didn't want to be so low on gas for the long drive today so I wanted to start with a full tank.

It stayed about 30 MPG indicated today so I'm going to leave it for the drive to the airport tomorrow and probably fill up on the way home from there on Friday and see what it does at that point.

[roddy]

I've had this happen a few times as well. Let the tank get down to 1/4 or so before filling up, and all should return to normal.

[BRZnut]

had this happen once when I top it off when I was only down 1/4.(ie still 3/4 full) The gauge did not go to full, but once the tank of gas was used, and I filled it up, it went to full. This happened ~ 2yrs ago and the gauge has been fine since (but, I usually run it down to 1/2 when I fill up)

[phobos512]

Ok so, drove home from the airport Friday and around a bit yesterday. Put just over nine gallons in the tank and it reset properly. Thanks!

That said, this whole issue seems very odd. Anyone have any idea why this happens? I've owned quite a few vehicles in my day and never encountered this before.

[DocWalt]

It's due to the way it filters out fuel sloshing around in the tank. It would be annoying if the gauge was constantly fluctuating, so it's programmed to ignore smaller changes in value like you'd get going from 7/8ths tank to full, for example.

[phobos512]

Originally Posted by DocWalt

It's due to the way it filters out fuel sloshing around in the tank. It would be annoying if the gauge was constantly fluctuating, so it's programmed to ignore smaller changes in value like you'd get going from 7/8ths tank to full, for example.

I can appreciate that but my issues occurred after I'd used the first quarter and refilled (3.5 gal ish). Far less than minimizing fluctuation due to sloshing about would require. And that still doesn't explain why it wouldn't go back up.

Does anyone know, for the MPG gauge is it performing a calculation or is the fuel actually metered someplace? Also, what would've happened if I hadn't refilled the tank and they gauge actually hit empty?

[DocWalt]

Originally Posted by phobos512

I can appreciate that but my issues occurred after I'd used the first quarter and refilled (3.5 gal ish). Far less than minimizing fluctuation due to sloshing about would require. And that still doesn't explain why it wouldn't go back up.

Does anyone know, for the MPG gauge is it performing a calculation or is the fuel actually metered someplace? Also, what would've happened if I hadn't refilled the tank and they gauge actually hit empty?

That's the only reason it didn't go back up. There's no direct link to the fuel gauge like you'd have on an old car so the ECU (or something, maybe the cluster itself) does some sort of filtering to damp the gauge. Maybe it decided that was a good time to calibrate itself? I dunno man

[Kevinn]

I had this happen once when I was low on gas, maybe less than a quarter tank left. I used a prepaid gas gift card that had maybe $10 left on it. Got back in the car, and the gauge never went up. It stayed at the current level until I burnt away that $10 in gas, then it started going back down as normal.

Got back into town, filled the tank full, and the gauge went to full. That was maybe 6 months ago, I'm sure it'd do it again if I only put a few gallons in.