I have a 2013 Grand Sport with a stock LS3. Two days ago I filled up the tank. The next morning there was a very strong gasoline odor in my garage. The smell was everywhere so I could not tell where it was coming from.

Then I parked the car outside and left it overnight. The next morning I checked under the hood and it is OK, but the gasoline odor is pretty strong in the interior.

What could be the cause of this? (Crack in the fuel tank, gas cap, fuel pump, or ???). Any other things I can do to diagnose this? TIA

 

Most likely a cracked fuel pump flange…there is a TSB for this but this “Special Coverage” is no longer covered on C6’s anymore.

 

Its starting to become more common as our cars get older. It the fuel pump plastic elbow will crack and leak fumes. If you drive it below 1/2 tank it will probably go away. You will need the fuel pump replaced. Which is not the easiest job on our cars. Mine does it too. I just make sure I have 1/2 a tank or less of fuel before parking it indoors.

 

Hopefully you just overfilled the gas tank and the smell will dissipate.
If not be prepared to do some reading and scavenging for in tank fuel lines, fuel pump, and assorted parts.
Longest thread on fuel tank leak/smell, there are many others on leak testing, fuel tank pump replacement and DIY options as the GM recall has expired.

 

Thanks everyone. Very useful information and the long thread will help too. I'm glad that I have backup transportation because this may take a while!

Will post here when I get this fixed.

 

Are there any parts that are no longer available from Chevrolet?

 

Rather than taking the gas tanks out, has anyone drilled a large enough hole in the bottom of rear hatch to get access to the top of the tank to replace the necessary items? Sorry OP, not trying to hijack your post but taking them down are PITA, most decent cars have access holes underneath the seat cushions like BMW.

 

Part of the frame goes through there. So you can't.

 

Keep it under half a tank in the mean time.

 

If the problem is a deteriorated seal where the fuel pump fits into the gas tank then that makes sense. I am going to drain the tank down to 1/4 and see if that helps.

But if the problem is a cracked plastic elbow on the high pressure side of the fuel pump, then it would seem that the fuel level would not matter -- it would leak whenever the fuel pump is on. Or am I missing something?

Also, can anyone tell me if the hoses and all the other parts needed for this repair are still available?

 

I stockpiled parts for my smelly 2011 Corvette about 2 months ago.

Link to fuel system parts for 2011 Corvette. This will give you some idea as to the state of GM parts availability.

As I only hopefully want to deal with this clusterfu fuel system design once I’m replacing as much as possible while the fuel tanks are removed.

I purchased Z06 fuel pump, driver fuel sense level kit, fuel feed hose, passenger side fuel module assembly with sensor, Fuel Tank Filler Vent Pipe Seals, Rear Auxiliary Fuel Feed and Return Pipe (Passenger intank hose) and driver in tank hose, silicone grease.

The intank hoses and fuel feed hose can be reused but are susceptible to damage during disassembly according to postings and may have long lead times if available.

Below are the part number replacements/cross-references I came up with. As I have not started work on the car part numbers below should be researched and verified for fit.

Fuel feed hose 15223882 replaced by 19436041

Rear Auxiliary Fuel Feed and Return Pipe (Passenger in tank hose) 19431776 used currently being advertised on Ebay from $80 to $375 used.

Z06 fuel pump 19420861

Passenger sending unit DELPHI FT4031 (came with fuel sense level)

Most parts were ordered from Rockauto.

I also had good luck ordering from Shea Chevrolet, found them helpful and cost effective. Eg Fuel Tank Filler Vent Pipe Seal - GM (10376929) $53.48

 

Thanks for the list of parts. I see that many of the parts are discontinued.

Are dealers still doing fuel pump replacements? I don't think I would be able to do this repair myself.

 

Ideally the fuel pump replacement should be done by a Corvette specialist, private or dealer who is familiar with completing the job without having to drop the transmission which is very labor intensive.

 

I called a dealer and the service writer quoted me $2800 labor plus the cost of a fuel pump. But the factory fuel pump is not available so they would have to use an aftermarket one. I asked about using a Z06 fuel pump (which is still available) and the guy said they could not guarantee it would work properly (no warranty).

... Today I removed the left rear wheel and fender liner so I could take a look at the fuel tank. I did not see any signs of a leak, but I could only see the bottom portion of the tank.

Then I removed 5 gallons of gasoline and took the car for a drive, parked in my garage and closed the door. I went in the garage 10 minutes later and didn't smell any gasoline. I estimate that there is now 12 1/2 gallons in the tanks. Will check the garage for gas fumes again in an hour or two.

 

It took a while, but several hours after going for a short drive my garage smells like gasoline. But the smell is not nearly as bad as when the car had a full 18 gallons. To be safe I opened both garage doors slightly to let it air out.

Will take out another 5 gallons tomorrow and find out if the gas smell goes away. It will be less than 1/2 full (7 1/2 gallons).

 

I emptied the tank down to 1/4 and the fuel smell is much stronger than it was at 3/4. I think our cars have different problems with the fuel system.

 

The fuel tank system in our cars is complex. Keeping your tank below a certain level will do nothing to prevent fumes getting out and could make the fumes worse. More air space means more space for fumes to accumulate.

Need to drop the tank and replace the pump. Nothing else will help.

I have done this job. It is not easy but is doable.

 

To get access, did you drop the transmission or just the exhaust?

 

Honestly, I don’t actually remember needing to drop the exhaust but I could be wrong. It has been a while since I replaced my fuel pump.

My car is a manual transmission GS so there is more room to work and you don’t need to drop the transmission. An automatic transmission car has much less room to work so likely do need to drop the trans and torque tube. It still was a fight to do the work on my car and I did have to do some stuff by feel since I could not get eyes directly on some areas such as the the bolt holding the crossover pipe.

The hardest part of the job is disconnecting the crossover pipe and holding it out of the way to be able to disconnect the two inner plastic tubes. It is important to not break the tubes themselves as these are on backorder everywhere and not available. So you can’t be an 800-lb gorilla with them.

Ideally, even if you have a manual transmission car, it may be worth the effort to get all of that out of the way so you have room to work. Otherwise it is a frustrating experience.

 

Mine is an automatic.

As for price, my best bet is an independent shop that specializes in GM. They are familiar with the problem.

But with the two inner plastic tubes being unavailable, I fear what would happen if the shop breaks them.

Do you think I should source some used tubes before I take the car to the shop?