Fuel Smell in Garage?
- Thread starter fsts2k
- Start date
Kevin, if you have any cars in your garage that are carbureted then you'll likely have a faint smell of fuel some, or all, of the time. It's the fuel in the float bowl evaporating out through the air filter in many cases, or the usual gradual seeping of fuel that carbs can allow for.
Sometimes the vent lines associated with the evap system on injected cars can go bad and allow fumes to seep out too - worth checking.
My wife calls it "gearhead cologne"
Sometimes the vent lines associated with the evap system on injected cars can go bad and allow fumes to seep out too - worth checking.
My wife calls it "gearhead cologne"
Seymour Snerd
Lifetime Supporter
Given you have an SPF it might be a problem to solve. Some of them have a leak around the top of the filler neck where it is welded intermittently ("skip welded"). Possibly your dealer will replace these. Search for Lynn Miner's posts, especially in the how-to section.
Also, EFI cars with long runs of fuel hose sometimes seep fuel through the hose itself.
And of course it wouldn't take much of a leak downstream from the fuel pump or downhill from the tank output to cause a problem. Since people seem to like multiple fuel pumps and labyrinthine fuel systems on these cars, there are a lot of connections to be concerned with. It just takes one galled or loose AN hose connection to do it.
X2 on what Alan said...
Also -
Beware of inexpensive or budget brand braided hose. This is a very common malady with less than premium hose. It's actually documented pretty well on other forums.. Like the fittings, I purchase only Aeroquip brand hose and fittings. I've not yet had a problem with either..
Venting of the fuel system -
You can run your vent lines through a charcoal canister system.. Go to your local Salvage yard and find the one that fits well in the space you have allocated.
Venting of the canister itself can be done in a number of ways. You can normally find the ventilation diagram on the underside of the hood from the car you take the canister from.
Also -
Beware of inexpensive or budget brand braided hose. This is a very common malady with less than premium hose. It's actually documented pretty well on other forums.. Like the fittings, I purchase only Aeroquip brand hose and fittings. I've not yet had a problem with either..
Venting of the fuel system -
You can run your vent lines through a charcoal canister system.. Go to your local Salvage yard and find the one that fits well in the space you have allocated.
Venting of the canister itself can be done in a number of ways. You can normally find the ventilation diagram on the underside of the hood from the car you take the canister from.
Jack Houpe
GT40s Supporter
There is no charcoal canister in these cars that I know of but is an excellent addition, being you have EFI the fuel is in movement all the time being pressurized and depressurized causing heating and vapor, the only way for the vapor to escape is through the fuel caps in the front. Most EFI SPF cars remove the rubber fuel cap gasket to allow move depressurization of the fuel tanks and yes it causes fuel smell in your garage most all the time except winter.
Not sure I am going to be able to determine this, therefore I will post a picture this weekend and maybe it will be obvious
I saw a post on this, based on the quality of most components I am hoping they are high end Teflon coated fuel lines but will check, good call.
Agreed, probably need to go through each connection one by one
Thanks Randy and Jack, good idea on the venting. Where would I look for the vent hose to route into the charcoal canister?
Jack Houpe
GT40s Supporter
Kevin you will have to make a line from the intake manifold to the canister and it will have to have a check valve in the line. Depending where you put the canister you will have to T into the fuel vents on the filler neck of each of the tanks. I hate to say it but it will be a lot of work, real tight spaces. Thats why my garage smells like gas.
Seymour Snerd
Lifetime Supporter
I'm sure I've seen a picture of the guilty filler neck somewhere; I'll try to find it.
Re finding a hose leak, you might consider one of these:
AN Hose Pressure Test Kits - SummitRacing.com
It allows me to plug one end of a line while the other end is closed with a schrader valve. Since my fuel system has a pressure gauge anyway, I just use shop air to pump it up and see if the gauge needle falls.
In the case of my car, where the fuel log ends in two separate hose barbs, I just put on a single piece of hose, one end on each barb and pressurise the other end at the gas tank fitting. Tests the whole system (except the tank and the carbs, obviously)
Also, there's an interesting thing to check on in the last post of this thread:
http://www.gt40s.com/forum/superformance-gt40s/29512-none-locking-gas-cap.html
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kevin,
If you have braided hose(s), and you don't know their age, or if you got any off Ebay etc., you need to put them through the bend test. Each size of AN hose is supposed to have a minimum radius of turn that it will sustain. You should put each hose through that bend and keep your ears open. Any fuel line that has been sitting idle for several months without fuel in them, will dry out and is subject to cracking when bent. If they are dried out then the fuel will work its way through the hose and you will get that constant smell. If you hear the crunching sound when bent, the hose needs to be thrown out. Oil lines and water lines are not so brittle. But if they have touched fuel any time in their life, then they will. I thought I was saving a bunch of money buying my fuel lines and An fittings off Ebay. We wound up throwing almost half of them out. didn't know about this until one fuel line leaked like a sieve. Then we tested and redid a bunch of them. So we probably came out about even.
Bill
If you have braided hose(s), and you don't know their age, or if you got any off Ebay etc., you need to put them through the bend test. Each size of AN hose is supposed to have a minimum radius of turn that it will sustain. You should put each hose through that bend and keep your ears open. Any fuel line that has been sitting idle for several months without fuel in them, will dry out and is subject to cracking when bent. If they are dried out then the fuel will work its way through the hose and you will get that constant smell. If you hear the crunching sound when bent, the hose needs to be thrown out. Oil lines and water lines are not so brittle. But if they have touched fuel any time in their life, then they will. I thought I was saving a bunch of money buying my fuel lines and An fittings off Ebay. We wound up throwing almost half of them out. didn't know about this until one fuel line leaked like a sieve. Then we tested and redid a bunch of them. So we probably came out about even.
Bill
Seymour Snerd
Lifetime Supporter
Here's a picture, courtesy of Lynn Miner, of the filler neck of P2133 taken from below where it's welded to its mounting collar, which in turn is sealed to the body with a cork gasket. Note that the weld around the top of the neck is not continuous. I believe this is a source of fuel vapor leakage.
Dimi Terleckyj
Lifetime Supporter
Hi Alan
From your photo I would suggest that if those rubber fuel hoses shown are not teflon lined you will get vapour leaching out through the rubber.
I used the best rubber fuel hoses I could get and still after about 7000 Kms I started getting fuel vapour smell so strong I could not stand to be in the car.
Replaced all the rubber hoses with Stainless braided teflon lined hoses and no more fuel smell.
Well worth the effort and cost.
Dimi
From your photo I would suggest that if those rubber fuel hoses shown are not teflon lined you will get vapour leaching out through the rubber.
I used the best rubber fuel hoses I could get and still after about 7000 Kms I started getting fuel vapour smell so strong I could not stand to be in the car.
Replaced all the rubber hoses with Stainless braided teflon lined hoses and no more fuel smell.
Well worth the effort and cost.
Dimi
Seymour Snerd
Lifetime Supporter
It turns out that on the upper side of that skip-welded flange, at least on my car P2160, the entire periphery of that joint is continuously welded. Thus interruptions in the weld underneath are not necessarily evidence of a leakage path. You can inspect the upper side by simply unscrewing all the SS flathead screws around the "Monza" cap and removing it.
I also discovered something else interesting about this construction. As you can see from the photo the steel filler tube with its welded-on flange is in turn attached to a ~6" dia. aluminum plate by four peripheral screws (one of which is visible in the photo). The steel flange and the aluminum plate (which is thin soft aluminum) are intended to be sealed to each other in order to prevent fuel overflow from draining down into the sponson rather than flowing down the hose to the right. On my car there were two problems with that:
- Any force on the filler neck flange or its surrounding aluminum plate can easily separate them and break that seal. This can easily happen removing the filler neck or the hoses attached to it. The plate should really be more like 1/8" thick. Pulling hard on the overflow hose barb can also distort the flange.
- Whoever applied sealant to mine didn't do it well enough to prevent a leak anyway.
- If yours is leaky and you spill any gasoline around the filler neck, it will leak into the sponson rather than running down the overflow tube to the ground.
- You could check for such a leak by temporarily plugging, say with a piece of tape, the overflow hole (~5 mm hole next to the filler cap), flooding the area with some harmless fluid, and checking for dripping into the sponson (which you would see by removing the sponson front access panel and inspecting around the front of the fuel tank).
- If you decide to remove your filler neck and/or the vent or drain hoses connected thereto, be very carefull not to bend the aluminum away from the steel flange in the vicinity of the drain hole.
- Better yet, or if your seal is already broken, you can easily fix the root cause by removing the filler neck and hose assembly, dissassemble the filler neck and plate, straighten the flange and the plate, seal both up properly, fasten back together with the four screws, and then add a fifth screw to the outside of the drain hole. This will vastly strengthen the structure around the drain hole. If you're more ambitious, make a new plate from something stiffer. It's just a huge washer with some holes drilled in it. 1/8" aluminum or 16 ga stainless seem about right.
Charlie Farley
Supporter
Don't light a match and go looking for the leak.
Why do you think i have no eyebrows ??
Why do you think i have no eyebrows ??
Seymour Snerd
Lifetime Supporter
Upon further research I re-discovered this related post:
http://www.gt40s.com/forum/superformance-gt40s/28382-gas-leak-very-puzzling.html
It turns out that "early"cars, P2160 included, do not have the sponsons and filler neck area isolated from the cabin. Later cars (I don't know the cutover) enclose the vertical channel through which the filler pipe runs in sheet metal so that any fuel or fuel vapor there or in the sponsons is kept away from you and your passenger.
That means that if you experience the leaking described in my post above, you're going to smell it inside the cabin, probably pretty much immediately.
No smoking.
It also occurs to me that the isolation implemented later is probably more crash-worthy in that if any part of the fuel storage (tanks and filler neck) are suddenly compressed (as in the famous picture of Mk II crash test below) perhaps the fuel will go "up and out" rather than all over you and your passenger who are sitting pretty much next to a couple worm-clamped rubber hoses that close the fuel storage.
With this knowledge in hand, I am motivated to investigate methods for retrofitting the same kind of isolation in my "early" (60+ cars =~ 1/4 of total production?) SPF GT40.
http://www.gt40s.com/forum/superformance-gt40s/28382-gas-leak-very-puzzling.html
It turns out that "early"cars, P2160 included, do not have the sponsons and filler neck area isolated from the cabin. Later cars (I don't know the cutover) enclose the vertical channel through which the filler pipe runs in sheet metal so that any fuel or fuel vapor there or in the sponsons is kept away from you and your passenger.
That means that if you experience the leaking described in my post above, you're going to smell it inside the cabin, probably pretty much immediately.
No smoking.
It also occurs to me that the isolation implemented later is probably more crash-worthy in that if any part of the fuel storage (tanks and filler neck) are suddenly compressed (as in the famous picture of Mk II crash test below) perhaps the fuel will go "up and out" rather than all over you and your passenger who are sitting pretty much next to a couple worm-clamped rubber hoses that close the fuel storage.
With this knowledge in hand, I am motivated to investigate methods for retrofitting the same kind of isolation in my "early" (60+ cars =~ 1/4 of total production?) SPF GT40.
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Seymour Snerd
Lifetime Supporter
I figured it was a natural consequence of messing around with all those 50-yr. old SW fuel pumps....:heart:
Seymour Snerd
Lifetime Supporter
In a conversation about something else Dennis Olthoff made a comment the other day related to this problem I thought I'd pass on. This issue was mentioned in another old thread but not quite in this context so I thought it would be good to gather all the causes in one place.
The locking fuel caps vent the tank to the atmosphere via a tiny maze-like structure inside the fuel cap. The "roof" of this maze is supposed to be the rubber gasket that seals the cap. However, that roof tends to sink into and therefore block the maze, which in turn blocks any venting. Whenever the fuel warms, the tank pressurizes and fuel vapor seeps out past the several hose-clamped connections in the filler neck, perhaps more suddenly than if the vent mechanism were working properly.
The fix is to bypass the mazed by cutting a groove across it deep enough that that the rubber gasket cannot sink in and block it. I don't recall the exact disassembly sequence for the cap but I do recall that it was simple and obvious.
The locking fuel caps vent the tank to the atmosphere via a tiny maze-like structure inside the fuel cap. The "roof" of this maze is supposed to be the rubber gasket that seals the cap. However, that roof tends to sink into and therefore block the maze, which in turn blocks any venting. Whenever the fuel warms, the tank pressurizes and fuel vapor seeps out past the several hose-clamped connections in the filler neck, perhaps more suddenly than if the vent mechanism were working properly.
The fix is to bypass the mazed by cutting a groove across it deep enough that that the rubber gasket cannot sink in and block it. I don't recall the exact disassembly sequence for the cap but I do recall that it was simple and obvious.
Seymour Snerd
Lifetime Supporter
One more thought on the fuel cap "maze" vent issue : If you want to get "diagnostic" about this you could use one of the two vent fittings (1/2" hose barb) either at the front of the tank or (more easily) near the top of the filler neck to pressurize (lightly!) the whole system to determine if and where it vents. You'd probably want to plug the hose(s) leading to your fuel pump, but at that point if you pump air into the system you should be able to detect it coming out of the sides of the fuel cap.
If not, it's either going somewhere else (and is thus possibly a source of fuel smell) or it's not venting at all (which means you have the above problem).
I did something similar with the tanks out of the car to make sure my fuel sender and gasket was not leaking, and plugged the tank spigot with a large rubber cork. At about 5 psi it popped out of the neck and shot up into the air in a very entertaining fashion. You can do the same thing with carefully-applied duct tape which will swell a bit under pressure and thus allows you to watch the pressure build (and release in the case of a leak).
If not, it's either going somewhere else (and is thus possibly a source of fuel smell) or it's not venting at all (which means you have the above problem).
I did something similar with the tanks out of the car to make sure my fuel sender and gasket was not leaking, and plugged the tank spigot with a large rubber cork. At about 5 psi it popped out of the neck and shot up into the air in a very entertaining fashion. You can do the same thing with carefully-applied duct tape which will swell a bit under pressure and thus allows you to watch the pressure build (and release in the case of a leak).
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