Elkriver
Member
I am having gasoline fumes bad at idle and highway speeds, any ideas what to check?
Gasoline fumes on my Cuda 440
- Thread starter Elkriver
- Start date
Xcudame
Well-Known Member
Choke first as Dave69 said. Also check and see if the carburator(s) are leaking onto the intake.
Deathproofcuda
Well-Known Member
Is this a recent problem/change on a car that is familiar to you, or is the car new to you?
Chryco Psycho
Well-Known Member
Tuning for sure
Also everything at the rear of the car , trunk seal , taillight seals , any open holes or rust in the rear 1/4 panels or trunk drops inside the 1/4s , you should not be smelling fumes at highway speed at all .
Also everything at the rear of the car , trunk seal , taillight seals , any open holes or rust in the rear 1/4 panels or trunk drops inside the 1/4s , you should not be smelling fumes at highway speed at all .
Mopars & Missiles
Well-Known Member
- Joined
- Jan 1, 2012
- Messages
- 234
- Reaction score
- 104
Check to make sure the VENT tube has a tube on it that runs outside of the trunk compartment. It should vent down under the car to the frame rail.
A previous owner of my Challenger had removed that line at some point, for some unknown reason and I had really bad gas fumes inside the car until I finally figured out that the vent line was missing. Fumes were just vented inside the trunk from the gas fill pipe, smelled so bad that I could hardly stand to drive the car. Installed a vent tube going under the car to frame rail and problem solved.
This is for a 70 Challenger, a Cuda may be different, and then again maybe not.
A previous owner of my Challenger had removed that line at some point, for some unknown reason and I had really bad gas fumes inside the car until I finally figured out that the vent line was missing. Fumes were just vented inside the trunk from the gas fill pipe, smelled so bad that I could hardly stand to drive the car. Installed a vent tube going under the car to frame rail and problem solved.
This is for a 70 Challenger, a Cuda may be different, and then again maybe not.
Last edited:
Elkriver
Member
all that is ok no fuel in oil and no sign of leakage?
Elkriver
Member
choke is working properly
Elkriver
Member
car is new to me but I just had the six pack carbs rebuilt and had the gas tank changed, I really never drove it before this change
Elkriver
Member
I will check for openings into the cabin space .
Elkriver
Member
I will check this diagram out and see what I have
Elkriver
Member
I did check the fuel pump and it seems to be an after market with *8lbs and 80GPH rating but it has no unit downstream to relieve the excess fuel r pressure? that may be a problem??
Deathproofcuda
Well-Known Member
Have you looked at the plugs?
Where is timing at?
How are your carb tuning skills?
You own a six pack carbureted musclecar. If you ever want it to live up to its potential, go buy a Holley book, a tuning kit, wideband O2 meter, and start watching some Youtube videos.
Where is timing at?
How are your carb tuning skills?
You own a six pack carbureted musclecar. If you ever want it to live up to its potential, go buy a Holley book, a tuning kit, wideband O2 meter, and start watching some Youtube videos.
sixpactogo
Well-Known Member
May not be your problem but one that I had a few years ago. My car always smelled of gas while driving and I could never figure out why. I checked for leakage everywhere and couldn't find it but stumbled on it by accident one day. It would never leak at idle but one day I was messing with the timing and had the engine revved to 2000 RPMs and noticed a drip at the fuel pump connection. It wasn't a bad leak but enough to cause the smell. Apparently it doesn't take much of a leak since I never saw any fluid on the ground or garage floor until that day. Hope you find it cuz I know how aggravating it can be.
I would pull the Air cleaner and do a real good inspection under the hood at high idle.
PS: I see you have no return line but that should not be your problem. If you develop vapor lock problems then you may need to add it.
I would pull the Air cleaner and do a real good inspection under the hood at high idle.
PS: I see you have no return line but that should not be your problem. If you develop vapor lock problems then you may need to add it.
Elkriver
Member
Just had the plugs and wires replaced again, less than 500 miles on last change, have a slight miss at idle but goes away on higher revs. I had the six pack carbs redone by a professional carb shop and they seem fine, I just want to be able to drive it without getting gassed to death. I had a 67SS chevelle that i did not drive enough and had a lifter stick on it and it would eventually free up after I drove it for while, the miss on the Cuda seems to mimic the same miss??, I am going to check the fuel lines for leaks at higher rpm's and see if I have something showing up and the vent line on the new tank, Thanks for the suggestions!
Deathproofcuda
Well-Known Member
Personally, I wouldn't hang my hat on the fact that a professional carb shop rebuilt your carbs, unless they also installed them on the car and then tuned it. If they didn't, then all they can provide is a general "out of the box" tuning setup that should at least allow the car to run. Since you can really F-up your car by running too lean, they probably err on the side of caution and have tuned the carbs to run slightly rich, just like Holley does from the factory. Just like any new out of the box carb, if you don't make the effort to tune it properly, you're leaving power on the table and will probably always smell like a gas station.
As far as plugs go, I wasn't suggesting that they are old. I'm asking if they look like the car is running too rich, which would point to a tuning issue as opposed to a fuel or exhaust leak into the car as others have suggested.
As far as timing goes, hopefully you are not just running it at the factory spec, which is like 5 degree BTDC for a 70 440-6 car. It's probably going to be happier with another 10 to 15 degrees of advance at idle, but that's a whole nother ball of wax to get into.
Good luck with it.
Check every hose, line, and connection for leaks. Then check your fuel pressure. Much more than 5# can cause eye burning richness and bleed over.
Chryco Psycho
Well-Known Member
8 PSI can over fill the carbs , you should be in the 5.5 PSi range , might need a regulator , have you checked the float height , it has to be done with the car running .
Elkriver
Member
Yes the plugs do indicate it is running rich, as far as the timing goes,, it starts right up without any hesitation, and seems to be ok on acceleration, a little hesitation, but runs out ok, but not what I thought the 3 duece setup used to be like on older carbs setups?! Anyway, that is another problem all to itself. I will check the float levels again, check for fuel leaks at a higher rpm, check for proper venting and maybe put a regulator inline before the carbs? depending on what pressures I find tomorrow, I am going to go buy or rent a gasoline pressure gauge outfit and know for sure the pressures I am working with. more info later, Thanks for all the help
I have seen stock low performance fuel pumps put out over 12# of pressure. Check the line pressure at the carbs with a t and a fuel pressure gauge. Thanks for letting us know it's a 6 pack set up. (at least we think it is) If it hs Holleys, a backfire could cause a blown power valve and a rich running condition. Any old Mopar mechanics in your area? It sounds like you may be over your head. 6 Packs can be a turd to set up correctly and keep adjusted and in tune.
Similar threads
