Z06 running out of gas

[SWO]

I'm a new forum member and first time Corvette owner. I bought a 2003 Z06 with 22,000 miles this Spring .The car was built in the latter half of 2003, so it has the FFS fuel system. Its been loads of fun to drive, but I am having a couple of issues with the fuel system. I'm having the common "gas gauge dropping to zero" issue so I did a forum search and found the the Techron fix. I would get a 1431 code, but after resetting the code, the gage would work as normal. The Techron fix seems to be starting to work. Now the gauge dropped in only one of my last 3 tanks of gas.


However, I can never put more than 11 to 13 gallons of gas in the car even if I completely run out of gas. The first time caught me by surprise, but luckily I was near a gas station so I was able to fill the tank. The car fired right up after I put in the gas. I didn't know if this was a fluke occurrence, so I carried some spare gas with me and drove some more. Same deal, I ran out of gas after about 240 miles and could not put more than 12 gallons in the car.


The car has two 9 gallon tanks, so I seems like fuel is not getting from one tank to the other. Since I can get about 11 gallons in the car when empty, at least some of the gas must be transferring, but not all of it. Does this mean I might have gas in one of the tanks that is many years old?

The previous owner did have some warranty work done last year. He took the car to the dealer for the gas gauge problem and the dealer dropped both tanks to check them and did the following work:

Replaced left fuel tank and installed new internals

Right fuel tank:
Replaced fuel tank module
Replaced level sensor, internal fuel lines, module seal


Any ideas for a fix? Unfortunately, the extended warranty is now expired, so I'll have to pay for any repairs myself.

[BruceF]

I'm confused. Are you actually running out of gas? To the point where the car stutters and shuts down and won't start? Or are you just having the gauge go to zero when it is ~3/8 full?

Also, what brand(s) of gas are you using?

[SWO]

Sorry, I actually have two issues with my fuel system. One is the gas gauge dropping to zero, which I believe is being fixed by the Techron treatment. I just included that information in case it was relevant to my second issue.

My main problem is running out of gas and not being able to put more than 11 to 13 gallons in the tank even after the car sputters and dies from a lack of fuel. The car starts right up again after putting in more gas. This leads me to believe that 6 to 8 gallons are not being consumed for some reason but the car thinks it is out of gas anyway after consuming only 11 to 13 gallons. This limits me to trips of about 220 miles before fill ups.

I've been trying different types of fuel to see if there was any difference. I've been mostly running Mobil. In my area, we are limited to Mobil, Sunoco, Gulf, and some local varieties. No Chevron or Shell is available.

[c4c5specialist]

Hi there,

With your FFS fuel system, Techron is not an accurate repair.

There is an updated fuel system calibration for your PCM. That is the first thing I would try.

When you run out of fuel, what does your fuel gauge read ??

The second thing is telling me that your jet pump is NOT transfering fuel OR your cannot fully FILL the system.

Either way, diagnostics is needed with a Tech2 and accurate determination of the system usage and ability to fill the tank.

Allthebest, c4c5

[SWO]

Originally Posted by c4c5specialist

Hi there,

With your FFS fuel system, Techron is not an accurate repair.

There is an updated fuel system calibration for your PCM. That is the first thing I would try.

When you run out of fuel, what does your fuel gauge read ??

The second thing is telling me that your jet pump is NOT transfering fuel OR your cannot fully FILL the system.

Either way, diagnostics is needed with a Tech2 and accurate determination of the system usage and ability to fill the tank.

Allthebest, c4c5

Thanks c4c5,

If I go to a repair shop, what would I call the updated fuel system calibration so they would know what I was talking about?

When I run out of gas, the fuel gauge will read at least 1/4 tank left. This has been pretty consistent.

I'm not familiar with a Tech2. I assume that I will have to go to a dealer for a Tech2 diagnosis, correct? Does the a Tech2 diagnose the problem very accurately, or is there still some guess work involved?

[c4c5specialist]

HI there,

The dealership will be able to update your calibration and you can ask for a confirmation printout with the part numbers and programming code PRIOR to having them do the work.

As for the Tech 2, the key is the technician behind the tool.

You must know what to LOOK for in the data.

I dont think you have any DTC, otherwise you would see the check engine light.

You need to find someone you trust to do this.

Allthebest, c4c5

[SWO]

Sorry, what does DTC mean?

Nevermind, I found it. Diagnostic Trouble Code. Thanks again.

[Junkman]

Print out this TSB, just in case the technician you use for some reason misses it. He should be directed to it but just to be safe, show it to him.

[SWO]

Awesome, thanks Junkman!

[froggy47]

Just to check the simple stuff also, when you fill & the pump shuts off, try putting the nozzle upside down & slowly add more gas. EPA regulates the shut off system on gas pump nozzles & it's a hair trigger shut off in many cases.

My car I always invert the nozzle even though the scary government sticker on the pump says you are committing a felony or some such rubbish if you do it.