pikemike428

Guys-

Need some help diagnosing this:

Everytime i fill up, I start the car, and the gas needle starts to rise, and then it gets up about half way and says Service Fuel System-CEL comes on, and then it shows that I am empty and then half way full then empty back and forth.

Eventually after some gas gets eaten up, it goes to where it should go, and CEL goes away.

Now I have another CEL from something else (I think) that I also have to deal with.

Any Ideas?

Z2Z

I would start by pulling the codes. Sounds to me like there could be something wrong with the fuel level sensor.

50 4Ever

Try this; next time you get gas, after shut down and you set the emergency brake - let the clutch out and press the start button. This will boot all computers and turn on all gauges. Then fill and watch the gas gauge. See if it goes crazy or slowly comes up.

Unreal

Sounds like the drivers side sensors is out.

C5 Hardtop

The C6 carried over fuel sensor problems from the C5. I've had this issue repeatedly where I'm driving on the freeway with a 3/4 tank and bam, out of fuel light and gauge goes to empty.

If you have to take it in for service, run as much gas out as possible so the mechanic wont have to pump the gas out before pulling the tank(s).

Once the gauge is operational again don't top off when you go to fill-up. There is something about adding more gas after the pump clicks off automatically that causes problems.

Unreal

I don't think it has anything to do with overfillling. That messes the charcoal canister up but not the sensors. The sensors are just crap, and go out. It sucks out hard they are to replace.

Undy

GM paid 50% of my out of warranty fuel sensor/pump replacement.

It would have been around $500 without GM's help, as I recall. One tank had to be dropped. There's a fuel level sensor printed circuit board in each of the two fuel tanks. There's a float level wiper arm in each tank that wipes across the circuit board as the fuel level goes up and down. Poor grade fuels, especially with high sulfur content, plate out deposits on the printed circuit boards. That causes intermittent loss of contact with the wiper arm. The car's self diagnostics picks up on it and that's sorta where the OP's at now.

Using two full-tilt-boogie 20oz bottles of Techron fuel system cleaner "may" solve your problems... but that's sometimes a short-lived fix.

AzDave47

I have read that Techron added to the fill also sometimes fixes the sensors, too. I have not experienced this problem.

Unreal

It can provide a temporary fix, but not a long term one.

MyOwn69

Have the same problem, shows "service fuel system", "low fuel", and empty. If I shut it off too soon (at least 20 miles to "clear" it up) I'll also get a check engine light the next time I start it.
If I go over 20 miles or so the codes all go away, the gauge goes to where it should be and all is good again.
Friend of mine has the same car (2009 Z) and was having the same problem and wanted it fixed, no matter what. $900 later at the dealer's he was happy again.
Me - I'll find an excuse to drive another 20 miles and save the $$$!

dcamick

What?????!!

Bill Dearborn

High sulfur content damages the sensors. It happens on every brand of car since they all pretty much use the same materials provided by the same suppliers. Corvettes may be more susceptible to problems because of the lack of use with the sensors sitting in high sulfur content gasoline for longer periods of time.

This happened to my C6Z two years ago. Suddenly the gas gauge wouldn't work properly and the Techron treatment didn't work anymore. The passenger side fuel level sensor was bad. It took two weeks for the dealership to get the sensor in and installed. The biggest problem was getting the fuel tank back into the car without any leaks. A real bear and the mechanic told me he never wants to do another one. Cost would have been $800 but GMPP covered everything.

Bill

0Anthony @ LGMotorsports

Check to see if the car has a TSB out for it first. Chances are they are going to have to pull the tank but it is worth a shot. I think some of the 07 and 08 cars had the TSB and it is pretty much just a reprogram of the box and your good to go.

pikemike428

Just bought a house, so will be backlogged for a bit until after the move but will update all as to result after I take to dealer...

Thanks for the feedback

MTPZ06

Second this...and it works. Had a fuel gauge with a mind of its own on my C5Z, and copious amounts of Techron remedied the issue...so I continued to add some every third tank for as long as I owned the car, and the issue never returned. Haven't had the issue with my C6Z, but I add a bottle every third tank or so as a preventative measure.

pikemike428

So dealer said it was a level sensor in tank #2. Also said the CEL is the speed sensor in one of my rear wheels.

These 2 things alone to fix was about a $2,400 estimate....

Anyone know a dealer or shop or mechanic in Miami that is good enough to fix both for far less?

Unreal

Local shop here was about $400 to drop tanks and replace sensors FYI. So that whole job should be in the $600-700 range with parts.

pikemike428

They said rear speed sensor is on the hub so you have to buy a new hub to replace. Honestly if I could get both done correctly by a reputable shop for under $1,000.00 I'll drop my car off today.

Unreal

Yes it is, but even so hubs are not that expensive.

Landru

Post your question w/ the SW Regional forum, here: https://www.corvetteforum.com/forums/southeast-42/

Has to be many HP shop in FL who w/could do what you need for a LOT less than any dealer, usually better quality work also.