Weird fuel gauge issue

Yesterday I dropped off my new Type R to get PPF installed. It had only 41 miles on the odometer and a the fuel gauge still showed it was full. On my way home, I noticed it showed less than half a tank. I know that it wasn't driven by the shop because the odometer didn't show any extra miles. I also happen to have a Progressive snapshot device plugged in - the reports show it was only started up a couple times and for only a minute each time.

When they installed the PPF, they lifted the front end up to work on the bumper. I can't imagine that gas could have drained out because of this, but could it have messed with with the level sensor? Anyone else have similar issues with the fuel gauge?

ShiftyTypeR said:

Yesterday I dropped off my new Type R to get PPF installed. It had only 41 miles on the odometer and a the fuel gauge still showed it was full. On my way home, I noticed it showed less than half a tank. I know that it wasn't driven by the shop because the odometer didn't show any extra miles. I also happen to have a Progressive snapshot device plugged in - the reports show it was only started up a couple times and for only a minute each time.

When they installed the PPF, they lifted the front end up to work on the bumper. I can't imagine that gas could have drained out because of this, but could it have messed with with the level sensor? Anyone else have similar issues with the fuel gauge?

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This is quite similar to ab issue I had. I have a 2017 Hatchback Sport Touring, I brought it in for an oil change a few months back. I was told it needed a software update, so I let them do it. And ever since then I have gone from an estimated 305 miles that normally showed on the dash, to 220. I made an appointment a couple weeks ago and they went through my car, said it was in perfect condition and they couldn't figure it out. They put a call in to the engineers and would get back to me. I got some bs about the car taking the average of how much gas I get and it would put up an estimate. I never had an issue before the update. And since the gas tank is only 10 gallons, I always fill it when I get gas. So that's what I was told and I don't believe it. The gauge is more accurate to me, but itsi annoying when the gas light comes on and I have a third tank still in there.

interesting, try to fill it up and record how much it takes and report back.

ShiftyTypeR said:

Yesterday I dropped off my new Type R to get PPF installed. It had only 41 miles on the odometer and a the fuel gauge still showed it was full. On my way home, I noticed it showed less than half a tank. I know that it wasn't driven by the shop because the odometer didn't show any extra miles. I also happen to have a Progressive snapshot device plugged in - the reports show it was only started up a couple times and for only a minute each time.

When they installed the PPF, they lifted the front end up to work on the bumper. I can't imagine that gas could have drained out because of this, but could it have messed with with the level sensor? Anyone else have similar issues with the fuel gauge?

Click to expand...

ShiftyTypeR said:

Yesterday I dropped off my new Type R to get PPF installed. It had only 41 miles on the odometer and a the fuel gauge still showed it was full. On my way home, I noticed it showed less than half a tank. I know that it wasn't driven by the shop because the odometer didn't show any extra miles. I also happen to have a Progressive snapshot device plugged in - the reports show it was only started up a couple times and for only a minute each time.

When they installed the PPF, they lifted the front end up to work on the bumper. I can't imagine that gas could have drained out because of this, but could it have messed with with the level sensor? Anyone else have similar issues with the fuel gauge?

Click to expand...

Pay special attention to the Fuel gauge when you go to start the car.
The gauge is actually a electro-mechanical meter, and it goes through an initialization when the ACC is turned on.

It SHOULD go down and bounce on the low stops a couple of times, (below where you can see it do this, but if you only turn on the ACC, (not start the engine), you should hear it and the temperature gauge), click as they bounce of their bottom stops.

They should them both rise to max (smoothly - actually small micro steps), and then it should go back down to their correct positions.. the temperature down to min if the engine is cold, and the fuel to whatever level the fuel is at..

It could be that your Fuel gauge is sticking, or the needle has not been correctly aligned with it's shaft.

I took one apart a few weeks ago, and it is very critical to get the needle shaft pushed back into the rotating part of the meter in the correct position, both angularity, and to the correct depth.

If your is sticking, I CANNOT see a dealer being able to take it apart, to fix it .. you will most likely need a replacement Gauge Unit, with its Odometer programmed to match the old Gauge unit.

NOTHING is easy with these modern cars when things go wrong -- everything is so highly integrated, and most units are only replaceable, and cannot cost effectively be repaired (at least by the Dealer).

BTW: If the fuel gauge sensor comes disconnected, the gauge will still go through it's initialization process, but will then move to the empty position (and fuel warning light will come on).

Also seem to recall there was a recall on some of the fuel sensors...but cannot remember for what years and model civics. (it was NOT for the 2018 si)

Note: The Gauges are not like a Analogue Multi-meter gauge, which will move to a set position on its range according to the supplied voltage. The Civic's gauges have to be driven to their required position, similar to a servo motor.
The meter can actually sit in about 3 different stable positions, for the same control input, so it is very important that they get driven correctly through their initialization sequence, and then positioned correctly without sticking, otherwise they can read incorrectly with a significant fixed Offset.

Its all great when it works, but if it goes wrong, it a total screw up !!!

I Also have a strange issue related to the fuel gage and the calculated remaining mileage left until empty tank. The tank is 47L and I typically average 8L/100km, so the range with full tank is like 600km. Everything was working fine until I took the car on a trackday and as you all know the fuel consumption is then around 25L/100km. The problem is now that 5 full normal driving tanks later, the calculated range with full tank is now only about 350km. This is really annoying and of course not correct. To me this looks like some software bug. Anyone else experiencing this?

Reset mpg / trips and then take your car battery and disconnect for 1/2 hour.

Read up to see if this might reset everything for the ecu to start picking up on your driving habits again

There is a TSB/Recall bulletin on the fuel level sensor, had it performed on my 19 Touring last Tuesday, I'll try to post the # later today.

It is a recall specifically for 2019 Civics, the Recall # is 19035, checks sensor & updates? Software/firmware.

Hope this is helpful

EnjoyDriving said:

interesting, try to fill it up and record how much it takes and report back.

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That's my plan. I don't drive it much yet, so it might be a few days.

PhilF said:

There is a TSB/Recall bulletin on the fuel level sensor, had it performed on my 19 Touring last Tuesday, I'll try to post the # later today.

It is a recall specifically for 2019 Civics, the Recall # is 19035, checks sensor & updates? Software/firmware.

Hope this is helpful

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I can't find anything on this, but thanks anyway.

I filled it up today while it was still reading just under half. It took 7 gallons and now it reads full again. So, I’m still confused how it went from full to less than half full without being driven because the sensor appears to be working correctly. I’ll just keep an eye on it I guess.

ShiftyTypeR said:

I filled it up today while it was still reading just under half. It took 7 gallons and now it reads full again. So, I’m still confused how it went from full to less than half full without being driven because the sensor appears to be working correctly. I’ll just keep an eye on it I guess.

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PhilF has your answer above - recall on fuel sensor for 2019 Civic.

the Recall # is 19035

Yep...
NHTSA ID Number: 10155368

Manufacturer Communication Number: A19-035

Summary

Service Bulletin - The PCM software misinterprets sensor inputs as a fuel sender issue, and sets DTC P0461 (Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit Range/Performance Problem)

wildbilly32 said:

Yep...
NHTSA ID Number: 10155368

Manufacturer Communication Number: A19-035

Summary

Service Bulletin - The PCM software misinterprets sensor inputs as a fuel sender issue, and sets DTC P0461 (Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit Range/Performance Problem)

Click to expand...

Thanks. I'm not getting a DTC, but I'm interested in seeing if I can find more info on this. Where did you find this info. When I search for recalls (at Honda's website, or nhtsa.gov with my VIN, nothing comes up. I've searched for the numbers above and can't find anything.

ShiftyTypeR said:

I filled it up today while it was still reading just under half. It took 7 gallons and now it reads full again. So, I’m still confused how it went from full to less than half full without being driven because the sensor appears to be working correctly. I’ll just keep an eye on it I guess.

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7 gallons is more than half a tank. When the light comes on in my 2018, it usually takes about 10 gallons (2.4 gal reserve I guess) to fill up.

Sounds like the real issue was when it was showing full.

ShiftyTypeR said:

Thanks. I'm not getting a DTC, but I'm interested in seeing if I can find more info on this. Where did you find this info. When I search for recalls (at Honda's website, or nhtsa.gov with my VIN, nothing comes up. I've searched for the numbers above and can't find anything.

Click to expand...

Here:
https://www-odi.nhtsa.dot.gov/owners/SearchSafetyIssues