My car was sitting in the garage for about a week after it was washed, so I decided to wax it yesterday. When I was doing the left rear quarter, I noticed a gas odor that smelled like it was coming from the wheel well (above the tire, under the panel). I took the gas cap off and heard the vapors escape (I guess it is still sealed).
Today, the smell seemed to go away. I started the car just now (fired right up with no SES). Let it run until warm (5-10 min). Went to the back and was able to smell a little bit of gas vapors (very faint).
I would have to be right near the fender/canister to smell it (can't smell it when I'm standing up, only when crouched down near that area). Is it normal to smell some fuel in this area? Thanks!
Full Version: Fuel odor near gas filler?
I think is alright to smell some gas but not too much especially when you are sitting on a full tank of some nice premium fuel.
By removing the fender wall from the driver's quarter panel you will see either a round cylindrical or boxed shaped object mounted on a clip. There are three lines 1) Gas Tank, 2) Purge 3) Air. This is called the EVAP Canister and what it does it recycles/neutralizes the gas vapors.
After some time, the elements inside (usually carbon/charcoal mixture) will be too concentrated with gas fumes and will begin to leak, hence the smell. I'm talking about after 130K miles maybe more. Getting a new one is about $100 bucks. One at a junkyard will work just fine. Careful when connecting the lines back if you decide to mess with it, you don't want your tank becoming too pressurized. check out this link:
http://motorage.search-autoparts.com/motor...558/article.pdf
By removing the fender wall from the driver's quarter panel you will see either a round cylindrical or boxed shaped object mounted on a clip. There are three lines 1) Gas Tank, 2) Purge 3) Air. This is called the EVAP Canister and what it does it recycles/neutralizes the gas vapors.
After some time, the elements inside (usually carbon/charcoal mixture) will be too concentrated with gas fumes and will begin to leak, hence the smell. I'm talking about after 130K miles maybe more. Getting a new one is about $100 bucks. One at a junkyard will work just fine. Careful when connecting the lines back if you decide to mess with it, you don't want your tank becoming too pressurized. check out this link:
http://motorage.search-autoparts.com/motor...558/article.pdf
I was checking it again today. Started the car, drove it, smelled nothing at the gas door while running (heard hissing sounds I assume from the canister). No SES light at all.
Turned the car off, and was able to smell some odor (smelled more like charcoal than actual gas vapors) right by the gas door in about 2-3 minutes.
EDIT -- Car only has 25,800 miles, and recently passed the Goodwrench multi-point vehicle inspection at a Pontiac dealer (according to the sheet, the fuel system was also checked for visible leaks).
Turned the car off, and was able to smell some odor (smelled more like charcoal than actual gas vapors) right by the gas door in about 2-3 minutes.
EDIT -- Car only has 25,800 miles, and recently passed the Goodwrench multi-point vehicle inspection at a Pontiac dealer (according to the sheet, the fuel system was also checked for visible leaks).
It is possible to have a cracked cannister and very possible to have some loose hoses within the system. The entire system is supposed to be vacuum tight and the charcoal is not supposed to allow smellable vapors to be released if it is properly sealed up.
A very common problem is overfilling the gas tank. The reason why you are supposed to stop filling at the first click is becuz it is possible, in extreme cases, to overfill the tank and then gasoline will drain into the vapor canister. Yeah, I know....I always filled mine up as far as it could be filled and didn't concern myself with the possibility of overfilling the tank.
A very common problem is overfilling the gas tank. The reason why you are supposed to stop filling at the first click is becuz it is possible, in extreme cases, to overfill the tank and then gasoline will drain into the vapor canister. Yeah, I know....I always filled mine up as far as it could be filled and didn't concern myself with the possibility of overfilling the tank.
Quick question.
Would I still hear a "whoosh" (vapors escaping) when I open the gas cap if there was a leak somewhere?
Would I still hear a "whoosh" (vapors escaping) when I open the gas cap if there was a leak somewhere?
Yes you would but only when the car is off especially if you have a filled tank with 91 octane fuel. Not too much though. When the engine is running the purge selenoid is recycling the fumes up front. Last time I went to the GM they quoted me at $170 for a new canister. Have you ever done any fuel pump work?
No fuel pump work done.
Yes I know the purge solenoid recycles the fumes when the engine is running. I don't smell anything in the back when the engine is running, and I hear a slight whistle near the canister. It's when I turn the car off that I smell some vapors, kinda like charcoal.
I just have a feeling that if I take it to the dealer they'll just say they don't smell anything unusual. I guess I'll have to check it out myself if you are not supposed to be able to smell anything near the fuel dor (I'm talking about my nose being only an inch or two from the fuel filler area, or sniffing down into the inner fender through the holes just under the gas cap).
Yes I know the purge solenoid recycles the fumes when the engine is running. I don't smell anything in the back when the engine is running, and I hear a slight whistle near the canister. It's when I turn the car off that I smell some vapors, kinda like charcoal.
I just have a feeling that if I take it to the dealer they'll just say they don't smell anything unusual. I guess I'll have to check it out myself if you are not supposed to be able to smell anything near the fuel dor (I'm talking about my nose being only an inch or two from the fuel filler area, or sniffing down into the inner fender through the holes just under the gas cap).
QUOTE(97 Formula @ Feb 28 2009, 09:59 AM) 
No fuel pump work done.
Yes I know the purge solenoid recycles the fumes when the engine is running. I don't smell anything in the back when the engine is running, and I hear a slight whistle near the canister. It's when I turn the car off that I smell some vapors, kinda like charcoal.
I just have a feeling that if I take it to the dealer they'll just say they don't smell anything unusual. I guess I'll have to check it out myself if you are not supposed to be able to smell anything near the fuel dor (I'm talking about my nose being only an inch or two from the fuel filler area, or sniffing down into the inner fender through the holes just under the gas cap).
Yes I know the purge solenoid recycles the fumes when the engine is running. I don't smell anything in the back when the engine is running, and I hear a slight whistle near the canister. It's when I turn the car off that I smell some vapors, kinda like charcoal.
I just have a feeling that if I take it to the dealer they'll just say they don't smell anything unusual. I guess I'll have to check it out myself if you are not supposed to be able to smell anything near the fuel dor (I'm talking about my nose being only an inch or two from the fuel filler area, or sniffing down into the inner fender through the holes just under the gas cap).
Have been thinking about this one for awhile. I also had a similar problem and tracked it down to rotten hoses back there by the vapor canister. The hoses were old and dried up--had to be replaced. I think that might by the problem.
That said, there were times when even after the repair, it was always a warm day in the spring, that a slight gas vapor could be smelled. It could be that with the high vaporization of winter gas, a warm day just overwhelms the vapor canister and some of the stuff gets out.
Maybe you should remove the inspection plate and check all the hose for possible cracking and sloppy fit. There is also an inherent bug back there....one of the hoses is glued to the nylon line that comes from the front of the car...the glue goes bad and the hose comes loose. I don't know of any way to fix this short of replacing the hose and using a small round spring type clamp (available at any parts store).
QUOTE(Me Too @ Mar 4 2009, 02:23 AM)
Have been thinking about this one for awhile. I also had a similar problem and tracked it down to rotten hoses back there by the vapor canister. The hoses were old and dried up--had to be replaced. I think that might by the problem.
That said, there were times when even after the repair, it was always a warm day in the spring, that a slight gas vapor could be smelled. It could be that with the high vaporization of winter gas, a warm day just overwhelms the vapor canister and some of the stuff gets out.
Maybe you should remove the inspection plate and check all the hose for possible cracking and sloppy fit. There is also an inherent bug back there....one of the hoses is glued to the nylon line that comes from the front of the car...the glue goes bad and the hose comes loose. I don't know of any way to fix this short of replacing the hose and using a small round spring type clamp (available at any parts store).
That said, there were times when even after the repair, it was always a warm day in the spring, that a slight gas vapor could be smelled. It could be that with the high vaporization of winter gas, a warm day just overwhelms the vapor canister and some of the stuff gets out.
Maybe you should remove the inspection plate and check all the hose for possible cracking and sloppy fit. There is also an inherent bug back there....one of the hoses is glued to the nylon line that comes from the front of the car...the glue goes bad and the hose comes loose. I don't know of any way to fix this short of replacing the hose and using a small round spring type clamp (available at any parts store).
I was also wondering if "hot" meeting "cold" has something to do with it. I just took it for a nice 15-20 minute ride (I don't drive it everyday). Still runs great, and still no SES light (I assume OBDII will care about even the slightest fuel leak, especially with the EVAP system).
However, it seems I still smell some gas vapors right after a ride, although it goes away pretty quick and just lingers around the fuel door/cap. And I usually smell it where the heat is tryung to escape from underneath the car (most likely from the exhaust).
take a look at the rubber ring around the gas cap. Is it dry or cracked? If so either get a new rubber ring see if that helps. New Gas Gaps with ventilator sell for around 20-25 bucks at the dealer. The ones at Autozone or O'Reileys (<--not Checkers anymore) are allright but if you look closely they have no ventilator. I think this could build up pressure in the tank.
QUOTE(xXGhosTBirDXx @ Mar 13 2009, 12:33 PM)
take a look at the rubber ring around the gas cap. Is it dry or cracked? If so either get a new rubber ring see if that helps. New Gas Gaps with ventilator sell for around 20-25 bucks at the dealer. The ones at Autozone or O'Reileys (<--not Checkers anymore) are allright but if you look closely they have no ventilator. I think this could build up pressure in the tank.
I recently replaced the gas cap (Stant locking gas cap, not vented). The original one was not a vented design either. I looked up the part for my car and according to the shet, this is the correct cap for my car.
As I stated before, I still hear a "whoosh" when I unloosen the gas cap, so I believe the rubber seal is seated properly. Are you saying I should be using a vented cap?
EDIT -- Or could it just be the gas cap saturated in fuel vapors (since it is not a vented cap)?
**FINAL EDIT** -- Apparently my replacement gas cap was defective. Just installed another new one, gas smell is gone!
I think I spoke too soon. After coming back from another ride, I was still able to notice some gas smell (not as much as before however, and once again, need to be very close to the gas cap to smell it).
My car is coming up for inspection soon (no SES light). Is there a chance I set off codes even though there is no SES light (if the computer thinks there is a leak in my fuel system)?
My car is coming up for inspection soon (no SES light). Is there a chance I set off codes even though there is no SES light (if the computer thinks there is a leak in my fuel system)?
nah i would not worry about it.
Just came back from another ride, still watching this closely.
I was still able to smell slight vapors from inside the gas door. But as I was backing up, I stopped smelling them. Then I smelled a slight vapor again as I crouched down beside the left rear tire (away from the gas door). Keep in mind the vapors are not very strong (nowhere near as strong as if I unlossened the gas cap).
I assume I don't have any current or pending trouble codes since the ride I took today was to the inspection station, and the car passed.
EDIT -- 2 hours later, no more smell anywhere. I wonder if what I was smelling could be unburnt exhaust fumes?
I was still able to smell slight vapors from inside the gas door. But as I was backing up, I stopped smelling them. Then I smelled a slight vapor again as I crouched down beside the left rear tire (away from the gas door). Keep in mind the vapors are not very strong (nowhere near as strong as if I unlossened the gas cap).
I assume I don't have any current or pending trouble codes since the ride I took today was to the inspection station, and the car passed.
EDIT -- 2 hours later, no more smell anywhere. I wonder if what I was smelling could be unburnt exhaust fumes?
You shouldn't smell any gas coming from anywhere. If the car had any gas vapors coming from it, it would have failed the GM/Federal tests for vapor emission. That said, it might be tuff to stop some vapors. The only thing that I can suggest is to remove the inspection cover at the rear of the left rear wheel well and start tracing the vacuum lines while looking for loose vacuum hoses. This is a problematic area on the car and once fixed with new vacuum hoses, it pretty much stays fixed.
Ok, I really think I fixed this one permanantly now.
I checked the canister once again and didn't smell anything in that area. So I examine the gas cap and once again, the seal was not sealing the cap to the filler properly.
After having another gas cap not sealing properly (Stant gas cap), I decided to try a CST locking cap (from Autozone). The cap itself looks weird, but the rubber seal looked better, and seems to work MUCH better. Now, I really can't smell anything anymore!
I checked the canister once again and didn't smell anything in that area. So I examine the gas cap and once again, the seal was not sealing the cap to the filler properly.
After having another gas cap not sealing properly (Stant gas cap), I decided to try a CST locking cap (from Autozone). The cap itself looks weird, but the rubber seal looked better, and seems to work MUCH better. Now, I really can't smell anything anymore!
I think that I mentioned in this thread or another about the GM gas cap. When they get old, the white plastic swells up and gives a false tight feeling--it clicks, but the 0-ring doesn't seal. Don't know whether it is age or exposure to gas vapors that causes this problem. I wrote to GM and even called them about this problem, but they wouldn't answer. If you tried a new GM cap and it still did the same thing, then it is age that does it--the plastic is unstable.
A vacuum leak at the cap will cause a problem with the way the engine runs. The vapor canister purge valve operates at a set engine parameter and if all it does is suck outside air instead of stored vapors in the vapor canister, the engine won't run properly at that time.
A vacuum leak at the cap will cause a problem with the way the engine runs. The vapor canister purge valve operates at a set engine parameter and if all it does is suck outside air instead of stored vapors in the vapor canister, the engine won't run properly at that time.
QUOTE(Me Too @ Apr 20 2009, 05:04 PM)
I think that I mentioned in this thread or another about the GM gas cap. When they get old, the white plastic swells up and gives a false tight feeling--it clicks, but the 0-ring doesn't seal. Don't know whether it is age or exposure to gas vapors that causes this problem. I wrote to GM and even called them about this problem, but they wouldn't answer. If you tried a new GM cap and it still did the same thing, then it is age that does it--the plastic is unstable.
A vacuum leak at the cap will cause a problem with the way the engine runs. The vapor canister purge valve operates at a set engine parameter and if all it does is suck outside air instead of stored vapors in the vapor canister, the engine won't run properly at that time.
A vacuum leak at the cap will cause a problem with the way the engine runs. The vapor canister purge valve operates at a set engine parameter and if all it does is suck outside air instead of stored vapors in the vapor canister, the engine won't run properly at that time.
Nope, the first 2 new caps I tried were made by Stant (locking gas cap). That's why I tried the CST from Autozonem so far so good (can't quite understand this since the very first Stant locking gas cap I installed 10 years ago worked fine all those years, and the new ones were not sealing properly within the first week of installation). I also can't figure out why the car passed inspection since the cap was not sealing properly (yes they did the gas cap test during inspection)??
Throughout the time I've been trying to troubleshoot this issue, I never had a drivability problem. The engine was (and is) still running great.
Thank's for this thead guys. Gotta go get my new tires for the Bird tomarrow, so anyway I noticed on my ''97 Saturn that the sealing surface was rusted on the gas filler as Me Too mentioned. Original GM cap. Mileage hasn't been the greatest (no codes) . figure I'll stop at Autozone and pick up a CST cap. I sanded the rust off today. Again, nice tip. 
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