Gearhead Jim

In almost three years/47k miles we've had our 2009 coupe, there have been two or three occasions when I filled the tank to the automatic shutoff (no spilled fuel) and then drove down a twisty road. After a couple of minutes, I could smell gas for a couple more minutes. Not super strong, but definitely noticable.

That sounds like the gas cap is leaking, but I've never had the warning for a loose cap or any other warning associated with the fuel system.

I thought that any kind of air leak in the system would throw a warning/code, but perhaps not?

BTW, I'm familiar with the "easy does it" technique of installing the cap and never seem to have any problems getting it on properly.

Suggestions?

AORoads

Have you seen any sign of dripping gas? My guess is still on the gas cap leaking and allowing some to slosh out. If, when you smell the gas, you pull over, open the gas door, see if there's any strong gas smell near the cap. I'm assuming you do the one or not more than two clicks on the cap.

Gearhead Jim

Never any sign of dripping gas under normal circumstances. When the smell does happen, I'm having so much fun that I can't bear to pull over to check it out.

Gearhead Jim

Filled it up today until the pump shut itself off (no spillage), put the cap on normally, and drove down a moderately twisty road getting about .70g on the car. No gas smell.

Does an intermittant problem make the gas cap a more likely cause, or less likely?

el es tu

Hey jim

Im dealing with Chevy customer assistance on my fuel leak. Ive had the smell since last year, but I hadnt ever had a gas cap code, until a week ago on startup (and it went away immediately). Well Id finally run out of patience (been waiting over a month for a reply from chevy - no problems/complaints with them as I understand these things take time - I jsut get anxious about fixing stuff and then HAVE to do somethign ) so I just spent the 13 bucks and bought an aftermarket cap to test if it could possibly be the issue (filled the car up the same as you then installed the new cap and immediately parked it without doing any driving).

After changing the cap I didnt notice any fuel smell so I switched back to the original and didnt get much smell (but there was still - some there) after waiting overnight. Then I went for a drive and parked it - a couple hours later (without having to retop the fuel) the garage reeked. Switched back to aftermarket and the smell went away.

I will retest this week by driving around with the new cap. And then letting it sit. Then retopping and letting it sit again.
If its definitely the cap Im goign to order the more expensive factory one (aftermarket doesnt have a hole to clip to the leash).


Chances are you might have a bad cap. Im just being really paranoid with overtesting because the top of my driver side tank looks like its had fluid run over the top of it at some point and I want to be absolutely sure its not fuel from a bad crossover pipe or neoperene seal.

hope this info helps!

AORoads

yes, I'd think it's possible to be a gas cap thing, Jim. probably under the right pressure which varies with ambient and car temp, it could push gases out (not necessarily gasoline). not that it's super expensive but isn't there a timeline thing on emissions control items to be replaced for free? time or mileage?

el es tu

ao here is the info chevy provided me:

2 yr / 24,000 mi

• Air injection reactor (AIR) pump, Air distributor and valves.
• Pulse AIR valve and associated parts.
• Positive crankcase ventilation (PCV) valve and associated parts.
• Exhaust gas recirculation (EGR) valve and associated controls.
• Power control and EFI systems. *
• Intake/exhaust manifolds turbocharger and supercharger.
• Catalytic converter system.
• Sealing devices and mounting hardware.
• Exhaust system up to the catalytic converter.
• Distributor parts and associated controls.
• Spark plugs and ignition wires. *
• Fuel tank filler cap restrictor and vapor control valves.
• Evaporative emission control carbon canister and associated controls.
• Emission related hoses, clamps, belts, pulleys, tubes, fittings and wiring harness used on the above components
• Mass Air Flow Sensor


8 Yr / 80,000 mi Selected Components

• Catalytic converter
• Vehicle control module
• Power control module

ThunderWheels

I am having an issue with smelling fuel. So far the problem has not been found but from time to time you smell it. Usually when the tank is more than half full. The dealer pressure checked the entire system and has not found it.

Gearhead Jim

BTW, I've got GMPP so that should save me the few bucks if i get a new cap.

AORoads

yes, Jim, I don't think they're quite as inexpensive as the glove box latch, but not super expensive.

thanks, el es. appreciate the info. I knew it was limited time.

el es tu

Update: Gas cap fixed the majority of the issue but there is still a very light smell (Id probably never have noticed it if I wasnt looking for it) - not sure if its residual or if I may have a leak at the top of the tank (still have to look into that), but regardless, the cap definitely needed replacement despite the fact that there wasnt a cel.

TheVetteLover

hi,

I am a new member here. I have a 2009 C6 base model and I've been noticing gas smell as soon as I open the door, the odor just comes there?

Dealer said there are no problems what so ever.

Everyone notices the smell ... so could it be that gas cap?!

I've been reading in the c5 forum about same complaint but majority turn out to be the fuel pressure regulator.

I search that for the C6 but I couldn't find any posts.

Any help/suggestions would be greatly appreciated.

Cheers

grandsport6

If you are in doubt take the car to the local emissions station and have the gas cap pressure checked. It's supposed to be part of the test I believe. Or just take the cap to test. That will tell.

wayback

Gas cap could be the problem. It could be that you are topping of the tank. Never add more fuel after the auto stop as that will cause fuel to spill and give you the smell.

Another problem could be the evap line on the fuel pump. Dealer did a smoke test on mine and found the evap line was cracked. Replaced the fuel pump under the power train warranty. No more gas smell!!

I smelled gas anytime the tank was over half full.

Hope this helps.

TheVetteLover

Much appreciated wayback! i'll start with replacing the cap since it's the least expensive option and see how it goes.

Thanks again!

crAzy

Yea I recently just noticed a light gas smell and this was from filling up. I removed the gas cap and put it back on and twisted it a few times. Can't say I have noticed the smell still, but we shall see. Never got any codes. Z06 has 43K miles on it. The mufflers are cut off, but that should not matter. Exhaust smell and gas smell are two different smells. Still have cats on as well. It is my daily. How much does one of those smoke tests run?

el es tu

look under the gas tank on the drivers side - the metal pan will look like its had streaks of fuel run on it over time while the passenger side will look clean

most of the fuel leak issues people have had relates to the the driver side tank's gasket that seals the sending unit to the tank

crAzy

Will check that out soon. Thanks.

cclive

You can get a new Stant gas cap at Walmart for $12...why not try one...for that kind of money, it's not even worth driving to the dealer and maybe getting another mediocre gas cap. The Stant is better anyway.

Gearhead Jim

Since I'm the OP, I should have posted that replacing the gas cap, almost two years ago, fixed the problem. Shame on me.


Absolutely no smell since then.