drseth

I am having the same problem. I am on my 3rd tank with Techron. The gauge has gone to 3/4 to empty twice now.

I am taking my car in next week for a PCM update, injector service, coolant flush, and manual transmission fluid change. Hopefully I won't see the P1431 for5 a long long time.

Choreo

This is why I never brag about Gas Mileage on my C5 - you have to get great mileage to offset the extra $12 of Techron per tank to keep the gas gauge semi-working.

Still surprised no 3rd party ever developed a better sender-unit solution. I don't see any other cars that have to guess at their fuel level. I have already replaced my senders once and I have spent hundreds of dollars in Techron (and BG 44K when the Techron quits working).

PEETYZ

Mine was acting up for sometime and still isnt 100% all the time but its pretty darn good. A techron bottle every now and then helps. Shell V Power gas seems to keep it pretty happy. I always reset trip A once I fill up just incase the gauge fails and wont come back with the diagnostics on the computer so I know roughly how many miles I have gone. OP keep trying the techron. Even filling then driving and letting it sit should help soak the senders.

What are the worst stations now? I noticed sunoco is bad. I thought it was the fuel of NASCAR!! I know Shell is Top tier and I guess BP has recently joined but what about some other main stream ones like Speedway and Marathon with STP!!!? haha I'm in Ohio and can find 93 pretty easy. Shell and BP like to price premium a bit higher than others but again I've always had luck with V power.

LoneStarFRC

Everyone new to this situation needs to keep in mind that sending unit contamination/failure itself, is NOT the sole cause of the fuel gauge being driven to "zero" by the pcm.

Those that may be, or are, unknowingly experiencing failure of the right tank siphon-jet pump, are going to be very surprised when they find themselves on the side of the road while awaiting the AAA guy to bring them gas.

IOW, just using the Trip odo to keep track of miles driven in order to ignore the fuel gauge "zeroing" out until they (hopefully) reach 300 - 350 miles driven, as some may be tempted to do, is going to BITE you.

At a minimum, I would recommend replacing the right tank pump/sender assembly if you have tried Techron (or some other fuel treatment) unsuccessfully.

riverrat68

Mine , like I said isn't zeroing out. It is only filling to half way. I think maybe my problem might be caused for the same reason???
Jerry

drseth

One problem with using the trip odometer in lieu of a malfunctioning fuel gauge is that, if the battery goes dead or is disconnected, the trip odometer goes to zero on the return of electric current. So, if you have driven 150 miles when the battery goes dead, you may run out of gas with 200 miles on the trip odometer.

Why would I know this? I had an Oldsmobile with the same problem and had to call AAA for a gas call.

vette.mix

don't think there is a recall considering GM put the same sensors in the C6

Dirty Harry

Had the issue with my 02 and after replacing the sending units in each tank 4 times I finally found out that top tier gas like Chevron or Texaco that has Techron in it is all you can use. Once I had changed out the units in each tank and always used the top tier I never had another issue. You can't use these off the wall brands like at grocery stores or convenience stores or Race Track, cheap fuels will ruin the units.

riverrat68

Is there a recall on the sending units or fuel cross over lines on the 08?
Jer

Vette Boy TN

I added Techron at about 3/4 tank and before it had used to a 1/4 tank the gauge was working again. Then I added another 20 oz of Techron to a topped off tank (EXXON no Texaco or Chevron within 50 miles of where I live still open) and the gauge registers almost a full tank but, not quite. Do I still have a problem?
Also, I've found a 100% gas station that says it does not add ethanol. Would that be better than one with 95% gas and 5% ethanol for the gauge issue and the car overall?

drseth

We must be in the same boat, because my fuel gauge pointer is on the mark below the full mark.

I just came home from the dealership, after having a radiator flush and refill, manual transmission fluid change, oil change,and a fuel injector service. The dealer said the injector service might help, since they also added this BG additive in the fuel tank. I filled it with 92 Octane, even waiting to see if it might take a while for the tanks to equalize and read full, but it still is at the mark below full on the gauge after fill up. If I get another P1243 code, I will let you know.

luke87gt

It's interesting...

Some people swear by the Techron and some people say Techron didn't help. For me it helps but doesn't cure the problem.

Some people say the PCM reflash cured the problem and some say it didn't help.

F YOU GM for designing such a POS fuel sensing/sending system and causing so many of us heart-ache.

Durran Ranney

can anyone that has had this reflash done for the fuel sending units tell me what is cost and how you went about explaining it to them

drseth

When I took the car in last week, they said the reflash had already been done. The reflash TSB was from 2003, so unless you have not been to the dealer since 2003, a reflash would help.

Reflash.....Check
Techron x 6.......Check
New Sending Unit......Next

drseth

I just came in from taking the car on a drive after replacing the right side Fuel Pump/Sender. I found an AC-Delco Unit on Amazon for less than $200, and it came today via UPS. I spent 3 hours total, most of it draining gas out of the tank, but it was very straightforward. My car did not require dropping the fuel tank, so it was a matter of jacking the car, removing the right rear wheel and inner fender, then remove a part of the tank shield held with a 10mm net and a 12mm bolt. From there the fuel pump/sending unit was looking at me. I unhooked the two fuel lines, the wire connector, and 6 7mm screws and it came right out!!!

After replacing the sender and putting everything back together, I went on a test ride. No runs, no drips, no errors, like Johnny Bench used to say. I did fill it up, which caused the fuel gauge to go just past the full mark. Previously it topped off at 7/8 tank when it was full.

I looked over the sender I took out, and the contacts were full of deposits that were so thick, my ohm meter could not register for most of the sweep. I took some emery cloth and gave it a good going over, and it worked perfectly.

Some thoughts. I am so glad I didn't let the dealership change it out, charging me $983.00. I got an AC Delco unit, same as the dealership specified, for under $200 on Amazon, and some sweat labor got it fixed. If I didn't have to drain gas, I could have done it in under 2 hours. Seeing how well the old fuel pump/sending unit is working now, I think my suggestion on someone having gas gauge problems is to remove it and clean it, and put it back in. I didn't need the fuel pump/sending unit after all. It just needed a good cleaning and light sanding.

Instead of almost $1000, I spent $200, but I could have fixed it for just my labor.

Something to think about.

drseth

And all of the Techron, BG Fuel System Cleaner, and the GM Fuel System Cleaner in the world could not remove the deposits that kept the sender from working correctly, but all it needed was some elbow grease and Emery Cloth.

luke87gt

It took about three treatments of Techron, but so far the gas gauge has been working normally for the last month or so... I'm not going to hold my breath however, lol

dagon138

When this happens it takes at least 3-4 treatments for mine to go back to normal. Happens I'd say every 2 years or so.

Cruncher

Since purchasing a new '03 Z06, I've used nothing but Chevron 99% of the time and the other times I've used Shell, Exxon, and Mobil, along with a 20 oz. bottle of Techron every 3K miles. My gas gausge doesn't work after 11 years. Techron isn't the entire answer.

luke87gt

Interestingly, my issue with the gas gauge is error when the car switches tanks (about halfway fuel capacity).

Wonder if there is a reflash for that?