Fuel gauge stuck at 2/3 full

[05 GRAND DADDY]

My fuel gauge has been stuck between 3/4 to 1/4 for over a year. Decided to be aggressive and put Techtron in every tankful for since pulling my XLR out of winter slumber. After about 4 tankfuls - I went to fill up the tank and the gauge went all the way to FULL! My trip to Virginia Beach gave me plenty of fuel to run through the car - I brought a few bottles with for the trip as well.

So far, so good - A few bucks for Techtron, and avoided hundreds of $'s to replace sending unit. I will be a regular user of it now.

If anyone else has fuel gauge issues - try the Techtron first... be patient, let it work.

I had the same issue Dave it turned out to be a corroded connector in the power lines to the tank!


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Dan & Wendy
"05 GRAND DADDY"

 

[DAVE JONES]

fuel gauge

My fuel gauge has been stuck between 3/4 to 1/4 for over a year. Decided to be aggressive and put Techtron in every tankful for since pulling my XLR out of winter slumber. After about 4 tankfuls - I went to fill up the tank and the gauge went all the way to FULL! My trip to Virginia Beach gave me plenty of fuel to run through the car - I brought a few bottles with for the trip as well.

So far, so good - A few bucks for Techtron, and avoided hundreds of $'s to replace sending unit. I will be a regular user of it now.

If anyone else has fuel gauge issues - try the Techtron first... be patient, let it work.

Thanks Dave, Trying the GM product now. Bought two bottles techtron in case that does not work. GM product is doing good job cleaning the injectors.

David J

 

[ccclarke]

I think we discussed the merits of Techron a few years ago here. There was a GM article about how well it cleaned the fuel senders to prevent erroneous readings as well. I run a bottle of Techron through the tank four times a year and have never had a problem with the fuel tank(s) level.

CCC

 

[DAVE JONES]

fuel gauge

I think I know the answer to this, but....

My fuel gauge has been stuck at 2/3 full for the last 400 miles. Oddly, there is no DTC currently set.

I plan on looking at the fuel sending unit readouts closely to figure out if (or which) tank has a faulty unit (if that is indeed the problem). Does anyone have any experience with this issue? Could it be a bad connector? Has anyone replaced the fuel level sensing unit(s) on their own? I'm aware of the complexity of doing it on my own, but I'd tackle it.

Most of the online searches I've done mention the fuel gauge at 0 rather than 2/3, which leads me to believe I might have an entirely different issue. Or do I?

I'm aware of the issue of a faulty board for the gauge sending unit, which, I would guess, is the issue, but I've been unable to find anything definitive as to if it's the drivers side or passengers side that has the issue.

Any input is appreciated. Thank you!

I have the same problem with fuel gauge. On full tank reads 3/4. Was suggested I use GM fuel treatment. Have gone thru 3 tanks using GM & last tank chevron. Did not work. Any suggestions before I go to expense of having tank pulled & replacing sending unit? Oh, the range read out is not correct either. Ran out of fuel depending on it. Oh, this is 4th tank & I hope it works.

 

[klaptrapper]

This is a common problem. The resistors in the fuel level sending units become coated and thus insulated from the wiper arm.
The rememdy is to add a full bottle of Techron to the fuel on fillup. It may take more than one tank full, but invariably removes the coating and restores the sending units.

I think I know the answer to this, but....

My fuel gauge has been stuck at 2/3 full for the last 400 miles. Oddly, there is no DTC currently set.

I plan on looking at the fuel sending unit readouts closely to figure out if (or which) tank has a faulty unit (if that is indeed the problem). Does anyone have any experience with this issue? Could it be a bad connector? Has anyone replaced the fuel level sensing unit(s) on their own? I'm aware of the complexity of doing it on my own, but I'd tackle it.

Most of the online searches I've done mention the fuel gauge at 0 rather than 2/3, which leads me to believe I might have an entirely different issue. Or do I?

I'm aware of the issue of a faulty board for the gauge sending unit, which, I would guess, is the issue, but I've been unable to find anything definitive as to if it's the drivers side or passengers side that has the issue.

Any input is appreciated. Thank you!

 

[lextoy]

xlr fuel capacity is 18 gallons.
18 gal X 20 mpg = 360 miles range
refill at 300 miles to be safe.
thats once a month for most of us
also could hot dose the tank with techron, add two bottles.
from the corvette forum, we have two fuel senders,
left and right, it can be difficult to get techron into the right tank
as the fuel splitter is above the tanks.
from corvetteforum ...
Success. After spending a hundred bucks on Techron this summer I finally figured out none of it was getting into the right tank which must have the dirty sensor. So a few days ago I filled the tank first and then added the Techron to get it into the right tank and today the gas gauge started working normally again. From now on I will put one bottle in before I fill up and a bottle in when it's full. Something to try if your gauge isn't working properly.


also maybe try this and let it sit in there for a week. its not how fast you can burn it off, its how long it stays in contact with the senders.
or try to do this over the winter storage period.

i would never pay $1600 to fix the fuel gauge. if it stays broken so be it.

 

[Phrede]

The right tank fills with overflow from the left tank. The right tank always empties first, then fuel starts being consumed from the left tank. So as long as there is less than 1/2 of total tank capacity, and you add the additive BEFORE adding any fuel, the additive will reach the right tank just fine. I prefer to go down to around 25% capacity. This allows for some mixing in the left tank before the right tank starts to fill.

The overflow line is near the top of the tanks but is NOT above them. Gravity is a wonderful thing.

FWIW, I don't drive near what you say most of us do.

 

[MarkSki]

Not sure I do know, do you know how much it takes to do the job? Is 20oz. overkill? I'm not a chemist so I don't think I'm qualified to go any deeper in this conversation. All I did was offer the information to those in need, I wasn't looking for a argument. I think the 100 degree heat is effecting everyone's testosterone, including mine.

I add the large bottle. I don't think it's overkill even if it is for a 20 gallon tank and I add it when I'm at a half of a tank or 10 gallons.

I tried a bottle of Stanadyne for gas, it was for an 18 gallon tank and I added it when I had 10 gallons already in the tank. I also had Techron in the tank, left over from my refueling the tank before.

I use Stanadyne for my diesel engine and I've used it since day one in the engine. With the low sulfur fuel with all of the lube oil taken to of the fuel this puts some of it back.

i was given the bottle for gas engines for free so what the heck, it works in my truck, lets see what it will do in the XLR.

After two tank full of gas we took a trip from Oregon to Reno NV. I did mainly 72 mph using cruise control and I watched my average MPG. The highest I saw was 30.2 mpg. Doing the math long hand the 1000 mile round trip, I ended up getting 28.8 mpg and this included a little city driving, into the city and then out of the city. The rest of our three day stay, the XLR stayed parked in the casino's garage. Reno isn't very big with most of the casino's on one street about 2 miles long. You can enter one casino and walking inside, you can walk to three other casino's without ever walking on the street.

Anyway getting back on track here, I'm going to get a couple more bottles of Stanadyne for gas and add it to my tank and see if I can't get my 22.5 mpg mixed city/country driving here at home, up a little to 24 or 25 mpg. If not I doubt the chemical is doing any harm, it cleans everything. Google it and see what you think.

 

[05 GRAND DADDY]

I had this same problem on a trip 2 years ago! I was actually running Seafoam Additive while on the long run thinking it was a good time to do so to clean the whole fuel system and injectors! When on our way to our destination we stop filled up and about 10 miles or so it showed only between 2/3 full! The gauge didn't work correctly after that even after running the 3 bottles Techron. So sent in to dealer and after 2 hours of diagnostic it turned out be nothing more than a corroded connection and about $200 labor bill! So before you spend money to drop the tanks double check all electrical connectors! BTW: it's been working correctly since the repair I believe they said they used some type of a electric wire connector lube to help keep it from corroding again! Hope this helps! Have a great day!


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Dan & Wendy
"05 GRAND DADDY"

 

[DAVE JONES]

fuel gauge

I had this same problem on a trip 2 years ago! I was actually running Seafoam Additive while on the long run thinking it was a good time to do so to clean the whole fuel system and injectors! When on our way to our destination we stop filled up and about 10 miles or so it showed only between 2/3 full! The gauge didn't work correctly after that even after running the 3 bottles Techron. So sent in to dealer and after 2 hours of diagnostic it turned out be nothing more than a corroded connection and about $200 labor bill! So before you spend money to drop the tanks double check all electrical connectors! BTW: it's been working correctly since the repair I believe they said they used some type of a electric wire connector lube to help keep it from corroding again! Hope this helps! Have a great day!


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Dan & Wendy
"05 GRAND DADDY"

Any idea where that connector was. I will try anything before pulling that tank.

David J.

 

[DAVE JONES]

fuel gauge

I add the large bottle. I don't think it's overkill even if it is for a 20 gallon tank and I add it when I'm at a half of a tank or 10 gallons.

I tried a bottle of Stanadyne for gas, it was for an 18 gallon tank and I added it when I had 10 gallons already in the tank. I also had Techron in the tank, left over from my refueling the tank before.

I use Stanadyne for my diesel engine and I've used it since day one in the engine. With the low sulfur fuel with all of the lube oil taken to of the fuel this puts some of it back.

i was given the bottle for gas engines for free so what the heck, it works in my truck, lets see what it will do in the XLR.

After two tank full of gas we took a trip from Oregon to Reno NV. I did mainly 72 mph using cruise control and I watched my average MPG. The highest I saw was 30.2 mpg. Doing the math long hand the 1000 mile round trip, I ended up getting 28.8 mpg and this included a little city driving, into the city and then out of the city. The rest of our three day stay, the XLR stayed parked in the casino's garage. Reno isn't very big with most of the casino's on one street about 2 miles long. You can enter one casino and walking inside, you can walk to three other casino's without ever walking on the street.

Anyway getting back on track here, I'm going to get a couple more bottles of Stanadyne for gas and add it to my tank and see if I can't get my 22.5 mpg mixed city/country driving here at home, up a little to 24 or 25 mpg. If not I doubt the chemical is doing any harm, it cleans everything. Google it and see what you think.

Where does one purchase Stanadyne?

David J.

 

[05 GRAND DADDY]

Any idea where that connector was. I will try anything before pulling that tank.

David J.

No I do not David, but if I get a chance on Monday I'll try and give the repair shop a call and see if they kept a record of which connector it may of been!


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Dan & Wendy
"05 GRAND DADDY"