Garage gas fumes

[67carry-all]

Was very excited to recently find garage space for my truck. Was very unexcited to find out shortly afterwards that the garage now is full of gasoline fumes. Near as I can tell, likely coming from the tank through the vented cap. I was hoping to have the garage as an enclosed work space for the truck, but not really possible due to the fumes. Better with the garage door open, but not so great with the current cold and rainy weather. Anyone else with this issue, and more importantly, good ideas on how to solve it?

[Accelo]

Very unlikely its from the venting cap. Epically this time of year.
I would look elsewhere.

[72afr]

Years ago, mine stank up from a cracked seal on the gas cap (not oem or oem style). Now it's from overfilling it.

[GASoline71]

Check all the rubber lines under the truck. There will be a short rubber fuel line from the tank to the hard line mounted on the frame, and then another from the hard line on the frame to the fuel pump. They get hard and brittle over time. Also check to see if the carb is leaking fuel at the throttle shafts, or from the fuel line inlet. What engine and carb do you have?

Gary

[howzzzit]

Originally Posted by GASoline71

Check all the rubber lines under the truck. There will be a short rubber fuel line from the tank to the hard line mounted on the frame, and then another from the hard line on the frame to the fuel pump. They get hard and brittle over time. Also check to see if the carb is leaking fuel at the throttle shafts, or from the fuel line inlet. What engine and carb do you have?

Gary

As stated the rubber line from the tank gets dry and brittle. On my 72 C10 there are 2 short rubber lines connecting the hard lines on the frame under the passenger door. Had one develop a bad leak while in the middle of nowhere and again in my driveway while warming up. I installed a new tank and ran new rubber lines where needed. I wish I had used fuel injector hose underneath. It isn't any fun trying to change those lines with fuel in the tank. Your lines may be slightly leaking. As you know it doesn't take much gas odor in your garage to perk up your senses. My truck has the charcoal canister. Had a little gas smell so I retrofitted to a newer style. Originals unavailable. Solved my gas odor issue. Good luck you'll find it.

[jabborabbo]

My garage has fumes were traced to a worn out fuel pump….

[howzzzit]

Originally Posted by jabborabbo

My garage has fumes were traced to a worn out fuel pump….

Good call. Had an Oreilly fuel pump with about 10 miles on it. Truck parked in garage for several weeks. Went out to the garage one night and smell a strong gas odor. The fuel pump was dripping from the cap where the pump was pressed onto the body. Like I said truck hadn't been driven in some time. Bought a better fuel pump. It's always something. Discovered a leaking wheel cylinder today. Crap.

[PbFut]

We, this could be a good thing. First, if the garage has any home appliances of any type, park truck outside until fixed. A pilot light or ignition spark can ignite gas vapors with really bad results. Even a light switch can light off vapors so be careful. It does not take much gas to stink up a garage. Look for signs of damp areas. May not be puddles. Also if it's a carb, hot engine will evap the drips and may not be easily seen. Good luck with the search. Mine was a hard hose at the pump to return line.

[don t. - 72gmc]

Put a piece (or pieces) of cardboard, red rosin paper, under your truck to find leaks.
HTH...Don.

[LUCKTRUCK]

for me, it was a leaking fuel pump. Never had issues with gas caps.

[jeffahart]

Originally Posted by 67carry-all

Was very excited to recently find garage space for my truck. Was very unexcited to find out shortly afterwards that the garage now is full of gasoline fumes. Near as I can tell, likely coming from the tank through the vented cap. I was hoping to have the garage as an enclosed work space for the truck, but not really possible due to the fumes. Better with the garage door open, but not so great with the current cold and rainy weather. Anyone else with this issue, and more importantly, good ideas on how to solve it?

I had this problem and solved it with a recirculating fuel line going through a filter with a vapor separator.

What happened and why this fixed it.
New gasoline blends have a low boiling point sometimes as low as 100 degrees. After the engine is shut off, it continues to heat up (no water or air flowing). Gas boils in carb, lines and pump. This floods the carb… and you smell gas. Plus, you have a hard start after engine sits about 15 minutes after a run.

Recirculating line routs the boiling gas back to the tank.
I did a recirculating setup with vapor separating filter. I don’t smell gas in my garage anymore, but I do still get an occasional hard start. I just slightly feather the pedal if the engine is warm and no problems.

Or you can move to an electric fuel pump in tank that requires a recirculating line. Or move to fuel injection. That is if heat soak is your problem.

Good Luck!

j

[72c20customcamper]

I get a gas smell when the we have these wide swings in temperature 40s-50s during the day and teens at night . My garages are not heated so it can swing by 20 degrees or more between night and day . It happens with every vehicle that vented to atmosphere. My Chevelle does it as the vent tube runs up into the trunk and then back down to outside under the car . As the tank cools at night it sucks in air and as it warms it expands and vents . When the temps are stable at real cold or warm the smell is gone .

[67carry-all]

Wow, great responses and ideas, thank you! The engine is a 292 with a period-correct Rochester 4G (4-jet) adapted to it (for a too-long explanation of why this carb, see this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=844048).

Pretty sure there's no leak at the carb end - there was after my initial carb rebuild, so I've been on top of it checking for leaks and it looks pretty well sealed up. The carb does vent the bowl to the atmosphere, but the gas smell can be so strong for so long, I'm thinking this isn't the problem (though it was one of the reasons I had a 2-bbl prior to this carb - I was able to vent the bowl to a carb canister).

I believe the fuel pump is ok, but I'll take a closer look at it over the next few days. How does one set up a recirculating fuel line with the filter and vapor separator? This is new to me - thought this was just for electric pumps/fuel injection.

I'll put some rosin paper under the truck after its next drive - curious as to what it may show. I'll take a look at the rubber lines under the truck - almost positive they're original; probably a good idea to replace them regardless. I'll also double check the seal on the gas cap. Light switch would be the only spark concern in the garage - I keep a window open to minimize the chance of too much vapor build up with a resulting unexpected surprise.

[HO455]

Is this on a Carry All? If so there is a short piece of fuel hose in the fuel line on the passenger side about where the B- pillar is.

Here are links for more information on EEC the fuel vapor system. If is is for a 67 Burban then you will have to add a vent tube in the tank. I put one in my sender as part of my plan to switch to a non-vented cap. The Burbans (And also Blazers I believe) have a different vent loop set up than the pickups do. Pickup vents in first photo.


https://67-72chevytrucks.com/vboard/...d.php?t=601940

https://www.67-72chevytrucks.com/vbo...d.php?t=842591

Suburban tank vent tube.

http://67-72chevytrucks.com/vboard/s...d.php?t=699716

And more information on Burban venting.

https://www.67-72chevytrucks.com/vbo...d.php?t=687417

[Papa Smurf]

Originally Posted by howzzzit

As stated the rubber line from the tank gets dry and brittle. On my 72 C10 there are 2 short rubber lines connecting the hard lines on the frame under the passenger door. Had one develop a bad leak while in the middle of nowhere and again in my driveway while warming up. I installed a new tank and ran new rubber lines where needed. I wish I had used fuel injector hose underneath. It isn't any fun trying to change those lines with fuel in the tank. Your lines may be slightly leaking. As you know it doesn't take much gas odor in your garage to perk up your senses. My truck has the charcoal canister. Had a little gas smell so I retrofitted to a newer style. Originals unavailable. Solved my gas odor issue. Good luck you'll find it.

Has this happen to me on a 72 sierra. Shop that installed a new gas tank used the old hose to reconnect to line going to the fuel pump. It was rotten and kinked. Didn't see drip on floor because it dripped inside frame rail and ran to the back. It evaporated before it could drip off. Still left the smell. It's an easy fix, but kinda hard to find.

[67carry-all]

Yes, I should have clarified, this is for my '67 Suburban. That B-pillar hose appears intact but original, so probably a good idea to replace it. No drips on the paper overnight after a drive and I don't smell any gas along the frame rails. The garage didn't smell too badly of gas this morning with overnight temps in the low 40's. The gas cap gasket is pretty badly cracked, so will replace the cap after it comes off back order. The venting info is interesting and very helpful; I'm going to do the simple stuff first and see how it goes and will look into venting the tank if needed. Would a new sender have a vent tube for this; would it need to be for a later model Suburban?

Thank you again for all the helpful responses.

[HO455]

I don't know if you can get a factory sender with the vent tube in it. I believe (but not positive) the later tanks had the vent in the tank not the sender.

I modified mine by drilled a hole in it and soldering a tube in. See the 2nd post down in the link.

http://67-72chevytrucks.com/vboard/s...698377&page=16

The PO of my truck couldn't get the engine to run with a no fuel situation. He replaced the fuel pump but it still wouldn't pick up fuel. He dropped the tank and replaced the sock still no fuel so he plumbed an electric fuel pump in by the fuel tank. He said when he turned the fuel pump on that little hose looked like a sprinkler in the yard. Fuel was spraying every where. The hose didn't leak with out pressure but sucked enough air to keep the mechanical fuel pump from pumping fuel to the carb. .

Having heard that story I always recommend replacing that hose.

[jeffahart]

Originally Posted by HO455

I don't know if you can get a factory sender with the vent tube in it. I believe (but not positive) the later tanks had the vent in the tank not the sender.

I modified mine by drilled a hole in it and soldering a tube in. See the 2nd post down in the link.

Ya, there's plenty of room on the top of that sender. I just drilled and used a bolt on bung and some washers. It's at the top of the tank, I've had no trouble with the bolt on. I used about 5" of rubber hose on both ends and hard line running down the tank and through the cab.... and so on.

It eliminated the gas smell when parked in the garage, but I still get some carb issues with that ethanol boil off. And it's worse with the low octane gas. That's been my experience so far.



j

[67carry-all]

Been a while since I posted about this, but figured I'd update - maybe it'll help someone else. I began (and ended) with a new gas cap. Took a bit of time before the vendor had one in stock, then I waited for warmer weather to see how the fumes were under different weather conditions. Bottom line - the new cap took care of about 99% of the fumes when the truck is parked in the garage, very happy about that (old cap rubber gasket was cracked and generally in poor shape)! This won't be the answer to everyone's issue like this (as noted by the various experiences above), but sometimes there's a simple answer to a problem. Wish it were all this easy!