Hello Folks
I have a 68 fastback Shelby tribute. All the body mods are similar to a shelby of the same year so hope someone has an idea of how to sort
Upon acceleration a very strong smell of petrol enters the cabin
Floats in carb are set correctly and zero petrol smell at the front of the car
I understand it can be the fuel filler rubber tube, the trunk lid seal, gas cap, exhaust tips not being long enough or gaps around tail lamps
My question is, what do you use to seal around the tail lamps and rear panel?
Cheers Peter
Look for leaky gas around the carb float bowl screws front and aft. I fixed that very problem on mine. Loose screw was letting gas percolate up the top of the carburetor.
But then you did say no smell of gas at front of the car.
Thank you. I will nonetheless look. Its such a sudden and heavy smell of gas immediately after acceleration its uncanny
Check the engine compartment while the engine is at idle and look for leaking gas around the carburetor then check the fuel lines. Also, buy yourself a fire extinguisher for any emergency while on the road. I have one in mine and thinking of getting a second one.
+1 on fire extinguisher(s) on board, and make sure they're Halon.
If you're describing fuel smell and not exhaust, then I'd also surmise it's something leaking at/in the carb.
If it's exhaust smell, my KR has always done that. I've always attributed that to exhaust entering through the trunk somewhere. Seems to be more prevalent at low road speeds.
But, that just smells like the 1960s to me. Part of the old car experience.
I realize that you're a very knowledgeable Mustang guy, so let us know what you find out the problem is.
I just had to change the fuel line. Seems 50 years old is a critical crossroad. The leak is usually just where you don't look.
Thanks folks
We have removed the bumper and tailight panel
Large gaps around the bumper mounts and zero sealing behind the decorative panel behind taillights
We will be dealing those up and see where we are
Also checking the carb as mentioned above but there is no smell at the front of the car.
It sure smells of fuel to me
Thanks for your suggestions. I sometimes think I know quite alot and othern times nothing at all
There was a recall on the 69 gas caps because the venting was igniting with the exhausts right below it. Put a non-vented cap on and see if the smell goes away?
Update
I have used thick plastic to cover the openings in the twilight panel, heavy duty the to secure. The rear panel attatched nicely and none of the plastic is visible from outside. I trimmed around the tail lamp openings in the rear panel and the lamps clipped in securing the plastic perfectly
I have noticed the flip open gas cap is missing the seal on the spring loaded piece that seals the tank
I also think the exhaust tips may be a bit short
I have driven the car yet to see if the smell has reduced
Cheers for all the advice
Peter
Quote from: shelbydoug on July 20, 2019, 01:27:23 PM
There was a recall on the 69 gas caps because the venting was igniting with the exhausts right below it. Put a non-vented cap on and see if the smell goes away?
Keep in mind that if you fit a non vented cap that you will have to add a vent somewhere else . You have to have a vent to allow air to displace the fuel in the tank as the fuelpump draws it out. In the case of the 69/70 Shelby the vent was added to the gas filler neck and routed over and down to the passenger side the wheel well and routed out of the trunk floor drop .
Agreed with Mr. Gaines.
This possibly/probably doesn't pertain to Mustang tanks, but I've been told that on Corvette tanks (C2 and C3) if you use a non-vented cap the gas tank itself can implode a bit as the gas gets used up and a vacuum inside is created.
Quote from: Bob Gaines on July 20, 2019, 07:21:29 PM
Quote from: shelbydoug on July 20, 2019, 01:27:23 PM
There was a recall on the 69 gas caps because the venting was igniting with the exhausts right below it. Put a non-vented cap on and see if the smell goes away?
Keep in mind that if you fit a non vented cap that you will have to add a vent somewhere else . You have to have a vent to allow air to displace the fuel in the tank as the fuelpump draws it out. In the case of the 69/70 Shelby the vent was added to the gas filler neck and routed over and down to the passenger side the wheel well and routed out of the trunk floor drop .
Probably some sort of a charcoal filter in that system would eliminate any possibility of fumes as well? You should be able to find one that works since all cars now have them new as part of the EVAP system.
Without a seal on cap, fuel can slosh out upon acceleration, esp. if tank pretty full. Even if the plastic stops the smell inside, you should of course address this issue.
Quote from: shelbydoug on July 21, 2019, 06:43:06 AM
Quote from: Bob Gaines on July 20, 2019, 07:21:29 PM
Quote from: shelbydoug on July 20, 2019, 01:27:23 PM
There was a recall on the 69 gas caps because the venting was igniting with the exhausts right below it. Put a non-vented cap on and see if the smell goes away?
Keep in mind that if you fit a non vented cap that you will have to add a vent somewhere else . You have to have a vent to allow air to displace the fuel in the tank as the fuelpump draws it out. In the case of the 69/70 Shelby the vent was added to the gas filler neck and routed over and down to the passenger side the wheel well and routed out of the trunk floor drop .
Probably some sort of a charcoal filter in that system would eliminate any possibility of fumes as well? You should be able to find one that works since all cars now have them new as part of the EVAP system.
No extra filter needed for 69/70 gas cap vent recall because the fumes were vented to the outside of the car.
Thanks folks for the advice, it is always appreciated
May I ask, if I want to install the cork gasket that is normally on the plunger portion of the flip down lid, what sort of adhesive I recommended?
Cheers. peter
Check that top of tank isn't rusty.
Quote from: Bob Gaines on July 21, 2019, 10:31:39 AM
Quote from: shelbydoug on July 21, 2019, 06:43:06 AM
Quote from: Bob Gaines on July 20, 2019, 07:21:29 PM
Quote from: shelbydoug on July 20, 2019, 01:27:23 PM
There was a recall on the 69 gas caps because the venting was igniting with the exhausts right below it. Put a non-vented cap on and see if the smell goes away?
Keep in mind that if you fit a non vented cap that you will have to add a vent somewhere else . You have to have a vent to allow air to displace the fuel in the tank as the fuelpump draws it out. In the case of the 69/70 Shelby the vent was added to the gas filler neck and routed over and down to the passenger side the wheel well and routed out of the trunk floor drop .
Probably some sort of a charcoal filter in that system would eliminate any possibility of fumes as well? You should be able to find one that works since all cars now have them new as part of the EVAP system.
No extra filter needed for 69/70 gas cap vent recall because the fumes were vented to the outside of the car.
You're missing the point. It is not "needed" but is helpful in eliminating the fume smell
Hello, 98SVT, Tank is as new
I had a car a few weeks ago. Was working on it, Real nice car, pulled up the trunk mat and noticed a glinting on the top of the tank.....nope, was seeing the fuel sloshing around!!!! there were bloody great holes in the top. Bottom looked perfect. Amazing the things you see working on these cars
Floors glued in, no welding
Full one piece USED floor pop riveted in
Rear quarters 25% made up of Galv sheetmetal that was skimmed both sides to hide the work to a causal glance.
Exposed wires from here to the moon
The fun continues
When there is a fuel smell inside the car from my experience it has always been because of one of the following problems:
1. The hood is not adjusted properly so that it is not contacting the rubber seal at the cowl. Hood adjustment required.
2. The rubber seal between the hood and the cowl is missing or torn or shrunken.
OMG that sounds like text for a lawsuit.
Hello, 98SVT, Tank is as new
I had a car a few weeks ago. Was working on it, Real nice car, pulled up the trunk mat and noticed a glinting on the top of the tank.....nope, was seeing the fuel sloshing around!!!! there were bloody great holes in the top. Bottom looked perfect. Amazing the things you see working on these cars
Floors glued in, no welding
Full one piece USED floor pop riveted in
Rear quarters 25% made up of Galv sheetmetal that was skimmed both sides to hide the work to a causal glance.
Exposed wires from here to the moon
The fun continues
Quote from: Royce Peterson on January 09, 2020, 09:12:57 AM
When there is a fuel smell inside the car from my experience it has always been because of one of the following problems:
1. The hood is not adjusted properly so that it is not contacting the rubber seal at the cowl. Hood adjustment required.
2. The rubber seal between the hood and the cowl is missing or torn or shrunken.
All good points and may be most typical on a regular Mustang but on a 67-68 Shelby it typically has to do with the poorly sealed tail panel more times then not. For those not familiar the sheet metal Mustang tail panel were cut out to make room for the Shelby taillight assemblies and fiberglass tail panel . 67 were especially cut out crudely. Wide gaps around the Shelby installed parts are consequently typical. Poorly sealed from the factory is putting it mildly. Some 67/68 were worse then others. The good news is that 68 Shelby's are easier to seal up the tail panel area then 67. There are various threads about sealing up for less smell. It sounds like the OP is on the right track.
This may or may not be of help but I have functional lower brake scoops and I was careful with the installation as far as making sure they sealed with strip caulk and silicone in addition to riveting the hoses back onto the flanges. What I found on my vehicle is that I had left the upper scoop vents open. I can only assume it was creating a vacuum and pulling exhaust in through the smallest of orifices. The tank was sealed with the strip caulk as well as the tail lamp panel from the inside and sealer was used from the panel to the edge of the trunk sheet metal. ( I have an early car with the flat panel that doesn't have the lip that rivets.)
-Keith
Just finishing up the story on some of my older posts
On this particular car we resealed the tail light panel. We removed the light panel, As Bob mentioned the openings for the back of the lights were letting the fumes in, We taped heavy duty black plastic over the whole area and put the light panel back in and then trimmed carefully where the sockets for the lights came through and inserted into the light panel, the sockets pinned the plastic against the tail lamp housings and this cured the fumes immediately.
Peter