woodvette03

fuel gauge reads empty and get low fuel warning after filling up. heard this is caused by deposits in the tank on sender. used about 10 cans of fuel system cleaners and no help. added it when tank was nearly empty so it would get to both tanks. at this point do i need to replace something or drop tank to clean sensor by hand? thanks

rrwirsi

Did you use Techron Complete Fuel System Cleaner additive? Do you put in high end premium gas like Shell? Your issue has been experienced by many and often it can be fixed by using Techron additive and top grade gas like Shell. Since owning my C5 for almost 4 years, I put in Techron every other tank full and use Shell. Never had a problem.

pewter99

you don't need to drop the tank....I did mine with the car on jack stands in my garage

similar to this http://www.superchevy.com/how-to/add...-sending-unit/

vetone86

pewter99

ouch...

woodvette03

used techron a few times, bk44, royal purple, and others. had this car for 10 years now and never had issues until the several months. i never used additives consistently but once n a while.

3sACROWD

Doing the work yourself would be significantly cheaper. If you have the tools and skill level to pull a wheel, you can do the job. Running the tanks to near empty is more challenging than the job itself.

laurent_zo6

If you need a straight answer, please call Rick at RKT Performance. I won't let anyone else work on my 2002 Z06. His shop is not that far from you.

http://www.rktperformance.com/contact/

birdsvette

Hi, I just bought a 2005 with 49,000 miles on it, and I'm having similar issues. Went I turn it on it's reading full, then dropped to just over 1/2 a tank, then just under 1/2, and dropped down to 0 and the check fuel system came on, but when I brought it back to the dealer they said they haven't seen anything irregular? I have only driven the car 60 miles total since I got her.

rrwirsi

You might want to post in the C6 forum. The dealer is trying to avoid the issue. Did they give you a warranty?

grinder11

It took me at least 8 bottles of Techron, and over 1,500 miles of driving before my 2000 C5 vert gauge started working correctly!!! Patience (and Techron!) is a virtue!!! Been using NOTHING but Shell premium since. No more Techron now, and no more problems......

DanTTVette

In my case, if I didn’t fill up at the local Chevron station every time, or religiously add Techron, my gauge would drop to zero, and the Low Fuel warning lamp would illuminate. Pretty common...
The Gauge would generally start working again after using up 1/2 a tank of fuel or so...

Checking my D.I.C, would show that P1431 was set (fuel level sensor 2). Clearing this error, would get the gauge working again. However clearing yours codes every start up gets old after a while.

I have a copy of HP Tuners, so was able to disable this error code. I have not had any problems with the gauge in 2 years now.

I’d check your codes after the gauge has failed, and if clearing any errors fixes the issue, pay a visit to your local tuner. It might be a cheaper option than dropping the tank etc..

Napoleon_Tanerite

Edit-- whoops, didn't notice that this was a revival of a 3 year old thread. I'll leave my answer up in case it can help someone in the future

Ok, here's the straight answer since everyone else is beating around the bush offering non-solutions. You have one or more sending units that has failed. This is a common problem in these cars. Techron and other cleaners is AT BEST a bandaid, and it sounds like you have already tried it. Time to replace the sending units.

Judging by your username, I'm going to guess you have a 2003 year model. This is tricky, because mid-2003 GM switched the tanks over from the C5 tanks to the C6 tanks. If you have the old tanks the job is MUCH easier because the sending units are on the sides of the tanks and can be changed without dropping the tanks. If you're like me and have a late 03 you're in for some fun.

1. Drain as much fuel from the system as possible. Either drive it or siphon it, either way. You need the weight gone.
2. Find a good guide on how to remove the C6 fuel tanks. There will be a few minor differences with the C5, but nothing signifcant.
3. THIS IS IMPORTANT-- This is a great opportunity to upgrade your fuel pumps. I'd recommend going with C6 Z06 fuel pumps. They drop right in. HERE IS THE IMPORTANT PART! I LEARNED THIS THE HARD WAY SO PAY ATTENTION!!! Despite having the C6 style fuel tanks, late 2003 and all 2004 C5s have their own sending units. The signal from C6 sending units is incompatible with the C5 system and will not read correctly. You MUST get sending units specified for the 2004 Corvette. They will look nearly identical to the C6 ones, and install the same way, but the 2004 ones will provide the correct signal.
4. Be careful putting everything back together. A little grease on the O-rings on the crossover pipe is strongly recommended.

Good luck. I'd rather slam my ***** in a sliding glass door than have to do that job again, and I had to do it THREE TIMES because of the C5/C6 fuel sending unit issue.

grinder11

On my 2000 vert, I've never gotten any codes for the sender. Kinda strange. But still working great now for the last 5 or 6 months..... .