Gas gauge shows tank is empty when it is full
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1st Gear
Joined: Jan 2020
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Gas gauge shows tank is empty when it is full
My 2014 Corvette C-7 gas gauge needle swings to full taken back to 0 on car start up but the gas gauge shows that the tank is empty when the gas tank is actually full
Team Owner
Joined: Jul 2004
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From: Hartford WI
Melting Slicks
Joined: Oct 2004
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From: Sunnyvale CA
A bad tank of gas can cause this due to a high sulphur content. If so, the problem might also go away on its own after a few tank-fulls. The suggestion to try Techron is also a good one.
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Melting Slicks
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Techron always helped my old C5 gauges. Worth a try.
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From: Chirper Island
Techron MAY help, it may not.
This happened to my first '14. I dosed it a few times, and finally gave up.
I recommend two things at this point:
1: Set your trip ODO and rely on this. Tune out the CEL.
2: If you have an active OnStar account, rely on the info it gives you. I have no idea where it gets its info for range, but it was always accurate. Even after filling up, so it's not just acting as a countdown .
Both are much less expensive options than having the sensor replaced.
This happened to my first '14. I dosed it a few times, and finally gave up.
I recommend two things at this point:
1: Set your trip ODO and rely on this. Tune out the CEL.
2: If you have an active OnStar account, rely on the info it gives you. I have no idea where it gets its info for range, but it was always accurate. Even after filling up, so it's not just acting as a countdown .
Both are much less expensive options than having the sensor replaced.
Drifting
Joined: Sep 2017
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From: Miami
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I had this happen to my C7 as well. Unfortunately, these are early indications of fuel pump failure.
I'd consider getting it to a dealership sooner rather than later.
I initially treated the tank with Techron, which did help, but one evening the car literally just shut off in the middle of the road during rush hour.
The fuel pump failed. It's a large and expensive project to replace the fuel pump.
I hope this isn't your issue, but something to think about from a safety perspective.
Good luck.
I'd consider getting it to a dealership sooner rather than later.
I initially treated the tank with Techron, which did help, but one evening the car literally just shut off in the middle of the road during rush hour.
The fuel pump failed. It's a large and expensive project to replace the fuel pump.
I hope this isn't your issue, but something to think about from a safety perspective.
Good luck.
Intermediate
Joined: Nov 2025
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From: Kansas
This weekend while at a road course track I was getting a check engine light (which was clearable) and my gas gauge was showing empty when I know it had gas. I was using 91 octane because I couldn't find 93. The 93 problem is solved, but still wondering about the two issues. Are they related, bad/questionable gas causing a dirty sensor?
I had a conversation with a guy at the track and he said the C7s have two tanks, one on the left and one on the right. Gas is pumped between them and there might be related to that.
I did get some Phillips 66 93 for the last session and no check engine light, but gauge still showed empty after a session. The tank was just above half before I started and I probably used about a quarter during the run.
I had a conversation with a guy at the track and he said the C7s have two tanks, one on the left and one on the right. Gas is pumped between them and there might be related to that.
I did get some Phillips 66 93 for the last session and no check engine light, but gauge still showed empty after a session. The tank was just above half before I started and I probably used about a quarter during the run.
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Joined: Jul 2004
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From: Hartford WI
This weekend while at a road course track I was getting a check engine light (which was clearable) and my gas gauge was showing empty when I know it had gas. I was using 91 octane because I couldn't find 93. The 93 problem is solved, but still wondering about the two issues. Are they related, bad/questionable gas causing a dirty sensor?
I had a conversation with a guy at the track and he said the C7s have two tanks, one on the left and one on the right. Gas is pumped between them and there might be related to that.
I did get some Phillips 66 93 for the last session and no check engine light, but gauge still showed empty after a session. The tank was just above half before I started and I probably used about a quarter during the run.
I had a conversation with a guy at the track and he said the C7s have two tanks, one on the left and one on the right. Gas is pumped between them and there might be related to that.
I did get some Phillips 66 93 for the last session and no check engine light, but gauge still showed empty after a session. The tank was just above half before I started and I probably used about a quarter during the run.
Instructor
Joined: Aug 2021
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From: Jacksonville Fl
I don't think an additive will fix a sending unit. The sending unit is the sensor that reads the level. There are 2.The drivers side has the fuel pump and a sending unit. Must be replaced as a unit. The passengers side is just a sending unit. One of them is malfunctioning.
If you drop the tanks I would replace both. It's not an easy job.
If you drop the tanks I would replace both. It's not an easy job.
Team Owner
Joined: Jul 2004
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From: Hartford WI
Allegedly, it cleans the rheostat. I'm skeptical but I've never had a float failure or pump failure and I run it to empty before I fill. One could theorize that it forces the arm to make a full sweep.
Race Director
Joined: May 2001
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From: Guelph, Ontario
This type of failure is exactly why you shouldn't store these cars with too much gas in them. Anything above 1/4 of a tank means the sending unit float is submerged in fuel for a long time and the sulfur in the fuel can damage that float.
Drifting
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