irfgt

Well, the dreaded fuel gauge gremlins have infested my 2003. As I understand it, the bulletin for reprogramming the ECM is up to 2002. Any thoughts? At A half tank the gauge went to empty and the Check Gauges light came on. I thought they had this fixed if the reprogram is up to 2002. DUH!

jeanlucpicard

Nope, sorry, it's not a programming problem. It's still the POS quality control related to the soldered connections on the circuit board that resides in the fuel tank. You have to remember that GM ordered a large gross (say 250,000 or so) of the circuit boards in 1996 to cover the expected 8 year manufacturing run of 30,000 to 35,000 units per year over the C5 life to get a low price. Means to say, they were all built years ago and they all suck the big weenie big time.

You should take the car in while it's still under warranty, have the tank dropped and the fuel sending system replaced. Happened to my 2001 when it was 6 months old and I've not have any problems since.

Good luck.

lager99

I've heard some people still have trouble after replacing the sending unit. :confused: I've never believed the "try another brand of gas" answer before, but the last 2 fills were at Shell and it hasn't happened since. :rolleyes: Could be a coincidence, dunno. :leaving:

Orbit

Welcome to the ongoing fuel gauge problems most C-5 owners have had once or twice. I have a 2000 which I have had to have repaired 2 times under warranty. This problem will go on until GM replaces the defective components, and that is not likely since this is the last year of the C-5. I guess we will live with it as long as we own C-5's. GM's new Logo "We'll be there". Don't know what it means but it doesn't mean they will be here to take care of our $45,000 to $55,000 corvettes. Maybe when the 2005 C-6 hits the street we will have fewer problems.
Fuel gauge (2 times), battery leak eating through a vacuum hose, console lid separation, differential leak, steering column lock up while out to dinner. What more can you ask for in a $45,000 car? Fun to drive? Most definitely! Just don't expect it to be perfect. Expect some problems.
:D

0vetteshop

In mid 2003 model year,the fuel tanks were redesigned and the fuel senders relocated toward the top of the tanks.Since you are having issues,you probably have the old design (same as 97-02) senders mounted at the bottom of the tanks...The updated PCM program for the fuel gauge issue went into factory production mid 2002 model year,and those vehicles are still having fuel gauge issues.The program was to make the PCM less sensitive to voltage spikes caused by sulfer content on the sender sensors...As you can see,it isnt working...

Unfortunately,you can replace the senders on your 2003 with the same parts,and the fault will most likely return in the future simply because it is a design defect...GM suggests changing fuel brands because they have determined that the problem is caused by sulfer build up on the sender sensor,changing the sensor resistance,causing a voltage spike to the PCM :rolleyes:You can also experiment by adding Chevron/Techron fuel additive to the tank to see if it helps,available at Wal-Mart.

Good luck.

mill_yel-MR

C5-TECH - Great reply and advise for all of us that have had this problem. My 2000 has been helped by the PCM program upgrade but it sounds like this may only be a temporary fix. The Chevron / Techron additive is a great tip.

Thanks for all your terrific posts !!

Sack Rat TT

You should take the car in while it's still under warranty, have the tank dropped and the fuel sending system replaced. Happened to my 2001 when it was 6 months old and I've not have any problems since.

:iagree:
You do not have to drop the tank to fix/replace the sender unit and pump. The left rear wheel- well inner liner is removed along with the metal, lower tank protector to gain access. Warranty should cover this for you.

:smash: :smash:

Cirrus8

Let me tell you that techron does not work. I have used Chevron gas with Techron additive and have also added Techron and ProTek in addition to the Chevron gas and my fuel gauge went south. I have tried other gasoline (Sinclair, Phillips 66, Tesoro) from time to time hoping that a change would make a difference --- IT DID NOT!! When my gauge drops to zero, I depress and hold OPTIONS and depress FUEL 4 times. The P1431 code appears and I press DELETE until the code goes away and the fuel gauge RETURNS TO NORMAL!! :D :D

irfgt

My car is almost exactly one year old and has less than 10,000 miles on it. Is is positively the left sending unit that fails? I have never understood the reason for two sending units since the fuel transfers anyway. Should both senders be replaced since the problem is so intermittent that there is no way to duplicate it?

kenrobb

My 03, built 7-30-02, had a stuck fuel gauge a couple of times early on. It stuck at 5/8 full for several hundred miles on a trip twice. I then put in several containers of Techron and have not had the problem reappear. I do now have the gas tanks full when I park the car for long periods of time. I had left the tank at 5/8 full before gauge stuck. I do drive with the trip odometer reset between fillups to watch MPG.

BlueDragon

Cheese-o-pete :confused: I had this on my 98 in December of 97, one would think they would have resolved it by now. Even if the have a 8 year run on inventory. Does the word rework ring a bell?? 8 years? Hummmmm, maybe two or three with contracts, but that is a lot to hold on the books, most manufactures do 2 or 3 with optional renewal contracts to cover the period.
Jer


[Modified by BlueDragon, 9:28 AM 9/15/2003]

MarginalTraction

I have an 02 with about 30k miles and my guage went South twice. Both times I added Techron and the problem cleared up. It may have cleared up anyway; no way of telling.
In my case, it does appear to be to be caused by "bad" gas, but there are other documented causes.
The lowest impact thing you can do is run though the gas you have in your tank and add Techron. You might want to switch brands for a while too, as it will take time for your current gas station to get a new batch of gas. Use one of the reset-able odometers to keep track of your mileage. If you have a general idea as to what kind of mileage you usually get, you should not run out of gas.
If your problem goes away in about two weeks, you probably don't need to make the "dreaded" dealer visit. The service department at my dealership is run by a Corvette enthusiast (has a Z06), so may risk is low, but you may not be so lucky...

fop91

I just purchased a 2004 cp. The fuel gauge dropped to empty from 3/4 tank on first fill up. my car had 100 miles on it and went back to dealer. they replaced both fuel modules and one fuel sensor. Working ok now but have not filled the tank yet since getting it back. Dealer also broke the fuel line clips. They had to order new lines in. Now it is back in the shop because the dealer chipped the paint on the bottom of drivers door on the lift pods. The way it is going I might never get car back to put gas in it. :mad

irfgt

There is one thing for damn sure, My car is npot going back to the Dealer for any work. They usually give me the parts and I do my own repairs on my Vette and Chrysler Sebring under Warranty. I also use the same fuel from the same Service Station in my 1965 Corvair and the fuel gauge works just fine as it has for going on 40 years. GM, don't give me any crap about bad gas, you have some crap parts that are giving problems and the inventory of the defective parts needs to be thrown out and some quality stuff introduced. It isn't as though the fuel gauge was just invented. :reddevil

irfgt

I have done some research into the Fuel sender problems and have found that what C-5 Tech says is true about a redesign of the tanks and fuel system in early to mid 2003 production. The Late or second design systems have what is called FFS, and it uses a returnless fuel system where the fuel pressure regulator is located insude the fuel tank. The Early or first design has the fuel pressure regulator and return line located in the fuel filter. Don't ask what FFS stands for because it cannot be found in the Factory Manuals or any other GM literature that I have been able to research. The early design allows you to replace the sending units from the bottom of the fuel tanks and the late design With FFS requires the removal of the tanks. It is almost impossible to look up the part numbers for the sending units too, for in the GM parts computer it shows sending units for the right and left side with FFS but only a left side without FFS. We phoned in for the part numbers to GM and they gave us numbers that are not even in the parts computer so we ordered them and I will post again when they arrive and see what shows up.