2017~2025: Fuel Gauge Stuck on Full
- Thread starter Defender
- Start date
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- 2018 CX-5 Sport
Never heard of this problem before. Does the estimated miles left work? You should keep a close eye on your miles to know when to get gas. I would take it to the dealer and try to have them fix it under warranty.
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- 2017 CX-5 GT
Yes, the estimated miles remaining does work. I reset every time I fill up and it typically shows about 300 odd miles. However, after traveling a little more than 100 with about 200 miles remaining, the gauge remains on full. I made an appointment with the dealer service department for next Thursday afternoon.
I played a practical joke on my girlfriend. I would go to her house every night and put a gallon of gas in her car (an older model that just had a gauge, not computer to empty mile reading). She thought she was getting great MPG since her gauge barely went down - if at all, She finally realized (wrongly) that her gauge must be broke so she went to fil it up. You should have heard her when she cam back and told me it only took 2 gallons (after 200 miles). I almost pee's myself from laughing inside, but could only hold out another 2 days before I told her what I was doing.
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- Occupied Calif.
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- 2019 CX 5 GT-R
Try adding 8 ounces of Marvel Mystery Oil to the gas tank and drive it until your best estimate is that you have about a quarter tank remaining.Then add 8 oinces again and fill up and drive a couple hundred miles. See if the gauge starts moving again.
Ethanol in gas has been known to cause sticky floats or sensors in gas tanks on some vehicles and the mild solvent properties of MMO might help.
Wonky fuel gauges were a known issue in Nissan 370Z's and an MMO treatment fixed the problem until after several tanks full of gas the gauge began acting up again and required another dose.
Ethanol in gas has been known to cause sticky floats or sensors in gas tanks on some vehicles and the mild solvent properties of MMO might help.
Wonky fuel gauges were a known issue in Nissan 370Z's and an MMO treatment fixed the problem until after several tanks full of gas the gauge began acting up again and required another dose.
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- Plano, Texas, USA
I’ve seen this problem a couple of times here before. Have you always been using Top-Tier gas?
You have new-car warranty, just let Mazda dealer to fix the problem. Please let us know what has the dealer done to fix the problem.
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- 2017 CX-5 GT
Always used the same gas station down the street (now Speedway for more than a decade, and always 89 Octane. I have a service appointment next Thursday afternoon at the dealership. Let's see what their solution is. In my case, 14100 miles in almost three years is not a whole lot of driving.
If you can, use top tier gas every time you fill up. It has the best detergent package. Here is a list of stations:
toptiergas.com
Fuel Stations - TOP TIER™
TOP TIER™ Licensed Brands prominently display the TOP TIER™ logo on the pump, pump handle, canopy or in a station window.
toptiergas.com
Thanks, DwightFrye, for bringing me back that memory...my 370Z had that problem. Was still under warranty so I let them fix it. Major deal, had to remove the tank, etc. My car stank of unleaded for a month after that. Fortunately, twas a convertible, so that helped me deal w/it. Great car, but I was always nervous about the top mechanism breaking...no cheap fix there. Anyway, OP, if it's not a warranty fix, I know I wouldn't bother!
This happened on my 17 Mazda 6 when it was on it's 1st tank. Gauge was at 1/4 and when I went to fill up the needle didn't move. I worked at Mazda at the time and mentioned it to the service dept manager. He said to drive it for a few hundred miles then fill up again and see if it would get jogged loose. It worked fine after that
This may very well be the problem.
I know it's not a car, but the theory is the same: the float on my snowblower engine would stick closed all the time, preventing the engine from getting gas and running. I'd have to clean it every time I used it.
I finally switched to a non ethanol high octane gas, and haven't had the problem since.
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- 2017 CX-5 GT
All good advice. I tried resetting a couple of times and gauge budged a little, but still shows close to full. Certainly not accurate given the amount of miles I have driven since the last gas refill. I will be taking it in to the dealership tomorrow afternoon.
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- 2017 CX-5 GT
Just returned from service department at the dealership. And perhaps predictably, they could not find anything wrong with the fuel gauge. We did a reset, and the gauge moved between the full and three-quarter level. They ran some codes and they all came back negative. The tech said, if there was a problem, the check-engine light would have come on. They did recommend, when filling gas, to cease filling gas once the first click sounded. Since this might mess with float in the gas tank. I have been guilty of topping off past the first click, and clicks following, to round up the dollar amount at the pump. As recommended, on this forum, I did pick up some Marvel Mystery Oil. Hopefully, this is the last I experience of this issue or non-issue. Thanks to all for their input.
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- Plano, Texas, USA
Thanks for the update. I believe using the Top-Tier gasoline is the key. I wouldn’t use Speedway if it’s not on Top-Tier gasoline list. Even Costco gas is Top-Tier gas but Sam Club gas is not.
Topping off the gas past the first click should not matter as I’ve been doing this to round up the dollar amount all the time. Just don’t try to fill the gas to the brim which could over-spill the gasoline. Also there’s a theory that doing that too many times would saturate the gasoline vapor canister and trigger the CEL.
Chris_Top_Her
Contributor
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- San Antonio, Texas
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- '15 CX-5 Miata AWD
I only top up the tank on my motorcycle.. since on that a pint of gas extra actually makes a difference. And beside, the overflow will just go into hole, tube then onto the ground 
Ya, I have heard from many sources that you shouldn't "top up" the tank after the nozzle pops off.I only top up the tank on my motorcycle.. since on that a pint of gas extra actually makes a difference. And beside, the overflow will just go into hole, tube then onto the ground
Filling the filler neck with gas is never a good idea.
I don't pay with cash anymore, so I never round off the dollar amount anymore.
If it stops at $32.64, so be it. That's where I stop. My credit card doesn't care about round numbers. lol
