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Fuel gauge not reading full after fillup (2014 GS)

pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
Howdy! I have 2014 GS with manual trans and only 34,000 miles. I recently filled up my gas tank until the pump "clicked" telling me that the tank is full. When I started the car and pulled away, the gas gauge was reading 7/8 full. I waited a few days without driving, still at 7/8. I topped off again yesterday with only 1.3 gallons until pump clicked, gauge still reading 7/8.

Has anyone dealt with this? Can anyone share their thoughts on where to start troubleshooting? Thanks in advance.
 

napacruzergs

Full Member
173
1
18
Napa, CA
Buick Ownership
Buick Regal GS
Various GM cars (Corvettes come to mind) have had fuel gauge/sender problems. What's worse is a gauge to read 1/2 tank and is actually almost empty. Common fix is to run a bottle of Chevron Techron Fuel System Cleaner through a full tank of gas. You may need multiple bottles. If that fixes the problem you may want to add some Techron on a regular basis (every other tank of gas, every 5k miles?).
 

pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
Various GM cars (Corvettes come to mind) have had fuel gauge/sender problems. What's worse is a gauge to read 1/2 tank and is actually almost empty. Common fix is to run a bottle of Chevron Techron Fuel System Cleaner through a full tank of gas. You may need multiple bottles. If that fixes the problem you may want to add some Techron on a regular basis (every other tank of gas, every 5k miles?).
at only 34,000 miles, could my fuel system be dirty enough to need a cleaner? all of my gas octane 91 comes from costco, annually reviewed to be on the cleanest fuels out there.
 

napacruzergs

Full Member
173
1
18
Napa, CA
Buick Ownership
Buick Regal GS
34k miles but almost 6=yrs old. Clean fuel does not mean clean station gas tanks. Also some "clean" fuels have high sulfer content which could cause fuel sender problems. Techron is a cheap PROBABLE fix. Try that before looking for mechanical solutions.
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pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
i have googled just about every site out there and found no help. Therefore I scheduled an appointment at local Denver dealer. i have serious doubts that a dealer can help, but worth checking out i guess.
 

BoostedRegal2.0

Well-known member
807
312
63
Buick Ownership
2014 Regal 2.0 Turbo AWD Trifecta Tune
Every time I fill up my car the gas gauge goes to the F mark. I had a new 2019 Buick Encore as a loaner the other day and the gauge stopped just shy of the F mark when I filled it up.

By the way the Encore with a 1.4 liter turbo is a dog compared to my 2.0 turbo Regal. Comparing engine output the 1.4 is 138hp/148tq and the 2.0 is 259hp/295tq so I can see why it felt so slow.

i have googled just about every site out there and found no help. Therefore I scheduled an appointment at local Denver dealer. i have serious doubts that a dealer can help, but worth checking out i guess.
Maybe it's the higher altitude of Denver that's causing the gas gauge to read slightly off the F mark.
 

pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
Ive owned my GS for 18 months and 8,000 miles now, all driven in Denver/CO at altitude and never had this problem before with ANY vehicle. Only use costco gas too, 91 octane because they don’t sell 93 here, and Costco gas is annually rated as one of the best, cleanest fuels you can buy.
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pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
How can I edit my thread title? Does a mod need to do it? Finally got a OBD code today and it is related to the fuel system

P12A6 = Fuel pump enable circuit voltage - performance
 

pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
I had a similar issue, the fuel gauge never read full. Dealer replaced the fuel level sensor under warranty.
Thank you for chiming in... did you ever have another problem? I ordered a replacement fuel pump flow control module (OEM ACDelco) from amazon only $50. Pretty easy to replace the module but still need to figure out if it requires programming at the stealership. Also don’t know if the fuel pump itself is faulty. I am no longer under any kind of warranty so hoping this is all easy peezy shadetree mechanic stuff.
 

BoostedRegal2.0

Well-known member
807
312
63
Buick Ownership
2014 Regal 2.0 Turbo AWD Trifecta Tune
I'm not sure about the Regal but some cars have an access panel to remove the fuel pump. If not the gas tank has to be removed to get to it.
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2007LucerneCXL

Full Member
3,121
937
113
Illinois
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
You may want to ask them, I know on the SUV'S recalls it needed reprogramming on that cluster for a correction. Who knows you may get the simple plug and play, but some how I get the feeling it needs to be calibrated to the other components in your vehicle, just a guess.
 

Classyceta

New member
5
1
3
Buick Ownership
‘17 Regal GS
I was going to create this topic as well!! Same issue as above! Once I fill up the GS, the level doesn’t go to F. It stops below the F.

I tried different gas stations as well as waited a few minutes before leaving and it still doesn’t reach F. Going to make an appointment with the dealer. The GS has 35k miles. (I drive over 100 miles a day)
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pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
I was going to create this topic as well!! Same issue as above! Once I fill up the GS, the level doesn’t go to F. It stops below the F.

I tried different gas stations as well as waited a few minutes before leaving and it still doesn’t reach F. Going to make an appointment with the dealer. The GS has 35k miles. (I drive over 100 miles a day)
My full tank reads about 7/8. I just passed 35k miles last week. My local mechanic is going to help me troubleshoot today or tomorrow depending on how much snow we get. Sorry to hear that you also have a similar problem. I will report back with an update hopefully in next few days...
 

pkgmsu2000

Contributing Member
173
18
18
Denver, CO
Buick Ownership
2014 Buick Regal GS
The dealer had to drop the tank to replace the sensor on mine. I'm glad it was covered under warranty.
Thank you for chiming in... do you have the paperwork from your warranty repair? What sensor part number? Because you also have 2014 GS very curious...
 
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