Gasoline odor

Richie
Richie Senior Contributor
edited November -1 in HUDSON
Hello everyone, could some of you more knowledgeable people please point me in the right direction to identify where a serious gas odor might be coming from. The gas odor only is there while driving, I have run the engine in the garage for hours at a time with no gas odor. In less than a mile of driving the gas smell is really bad. I stopped the car several times and opened the hood quickly and there is no sign of a gas leak. I took the gas tank off today thinking maybe the vent on top was leaking and the fumes were being sucked up in the trunk and into the interior. No leak at the vent, just replaced the hose and clamps, but still have the smell. I ran the engine in the garage for 30 minutes tonight at low and high rpm and cannot find any visible leaks. The fuel pump is dry at all rpms. Checked all lines and connections while running in the garage. Any ideas are appreciated, thanks, Richie.

Comments

  • faustmb
    faustmb Senior Contributor
    My car had it's share of gas fumes. The largest offender was a leaky fuel pump. I installed an AMC pump and the fumes are gone. I would remove the air cleaner while you look for leaks to be sure you have good visibility of the entire carb. I still have a small leak around the butterfly shaft, but it's not large enough to create a drip or a noticable odor.



    Also check all of the lines from the carb to the hard line under the frame rail very thoroughly. I had a leak at that connection due to a damaged fitting. It's hard to see from above.



    Matt
  • Richie
    Richie Senior Contributor
    faustmb wrote:
    My car had it's share of gas fumes. The largest offender was a leaky fuel pump. I installed an AMC pump and the fumes are gone. I would remove the air cleaner while you look for leaks to be sure you have good visibility of the entire carb. I still have a small leak around the butterfly shaft, but it's not large enough to create a drip or a noticable odor.



    Also check all of the lines from the carb to the hard line under the frame rail very thoroughly. I had a leak at that connection due to a damaged fitting. It's hard to see from above.



    Matt



    Thanks Matt, I will remove the air filter tomorrow and see what happens. I followed the hard line from the fuel pump all the way back to the tank and found no leaks with the car running and also with it not running. Thanks again. Richie.
  • Unknown
    Unknown
    I don't exactly fit into the "knowledgeable" group, but my stepdown had constant fumes a while back. Mine also only smelled while driving, mostly after making right turns.



    I did the same as you, started looking at the usual suspects up front and underneath, but had no success. The fumes were strong enough to give you a headache.



    There is a "vent" hose that goes from the top left rear of the gas tank, that goes over the frame rail, through the trunk floor, and then attaches to the gas tank filler neck inside the trunk. The fitting/connection on my car was cracked and loose allowing fumes to escape into the trunk/car but did not ever look wet.



    I bought a brass fitting with threads and screwed it into the filler neck where it was previously attached, re-attached the hose and the fumes are gone.



    You might take a look. It was an easy fix..... once I found it.



    Terry
  • Clutchguy
    Clutchguy Senior Contributor
    Richie,you need to check the gas cap real close.Sometimes the gasket shrinks around the cap and then allows the gas fumes to come into the trunk via around the filler neck rubber seal inside the gas tank door.I have looked for this very smell,and it doesn't seem to be leaking and does not smell just sitting.I believe the fuel sloshing around in the tank while driving causes the vapors,then since the car is traveling at some kind of speed,it allows it to push those vapors into the trunk.An easy way to check this is to seal off the rubber gasket,and then leave the gas tank door open while test driving the car.After driving the car,open the trunk and verify the smell is not stronger than before your test drive.Also make sure to pull the engine oil dipstick and verify there is no fuel smell to it,just for safety.
  • bob ward
    bob ward Senior Contributor
    Also check the soldered connection where the fuel pipe comes out through the tank. As it is up high on the tank, it only has petrol against it when you are on the move or when you have a very full tank.
  • Geoff
    Geoff Senior Contributor
    I go along with the advice already given, it is obviously movement of the car that is causing the problem. Perhaps the fuel outlet fitting , or a bad gasket around the fuel sender unit? Good luck.
  • Richie
    Richie Senior Contributor
    52 kahuna wrote:
    I don't exactly fit into the "knowledgeable" group, but my stepdown had constant fumes a while back. Mine also only smelled while driving, mostly after making right turns.



    I did the same as you, started looking at the usual suspects up front and underneath, but had no success. The fumes were strong enough to give you a headache.



    There is a "vent" hose that goes from the top left rear of the gas tank, that goes over the frame rail, through the trunk floor, and then attaches to the gas tank filler neck inside the trunk. The fitting/connection on my car was cracked and loose allowing fumes to escape into the trunk/car but did not ever look wet.



    I bought a brass fitting with threads and screwed it into the filler neck where it was previously attached, re-attached the hose and the fumes are gone.



    You might take a look. It was an easy fix..... once I found it.



    Terry



    Thanks Terry, I will give that a check today, hope it is that easy !! Richie.
  • Richie
    Richie Senior Contributor
    Clutch guy wrote:
    Richie,you need to check the gas cap real close.Sometimes the gasket shrinks around the cap and then allows the gas fumes to come into the trunk via around the filler neck rubber seal inside the gas tank door.I have looked for this very smell,and it doesn't seem to be leaking and does not smell just sitting.I believe the fuel sloshing around in the tank while driving causes the vapors,then since the car is traveling at some kind of speed,it allows it to push those vapors into the trunk.An easy way to check this is to seal off the rubber gasket,and then leave the gas tank door open while test driving the car.After driving the car,open the trunk and verify the smell is not stronger than before your test drive.Also make sure to pull the engine oil dipstick and verify there is no fuel smell to it,just for safety.



    Doug, thanks for that idea, I will try that today. I did check the oil level several times to be sure it did not increase and that there was no smell of gas. I will seal that filler tube gasket and do as you suggested. Thanks, Richie.
  • Richie
    Richie Senior Contributor
    Bob Ward, thank you , I checked the fuel line connection and fittings at the tank when I had the tank out. I also pulled the sending unit out and made sure that all gaskets were sealed good. No sign of leaks even when I turned the tank up on its side to test for leaks, There was about a gallon of gas still in the tank. No leaks at those points. Thanks again, Richie.
  • Richie
    Richie Senior Contributor
    Geoff C., N.Z. wrote:
    I go along with the advice already given, it is obviously movement of the car that is causing the problem. Perhaps the fuel outlet fitting , or a bad gasket around the fuel sender unit? Good luck.



    Geoff C., Thank you for your input. I did check the outlet fitting and also the sending unit & gasket. I will re-check all that today. I believe you are right about the movement of the car causing the problem. Thanks again, Richie
  • [Deleted User]
    [Deleted User]
    Richie,

    I had a strong gas odor when driving my 54. I too thought it might be the vent tube at the trunk. Then I noticed that it was not as strong when my cowl vent was closed. I couldn't find any leaks, so I decided to check the carb settings. My float level was way too high! I lowered it and have not had the odor since. It may re-occur but for now it is gone.
    Bob
  • Richie
    Richie Senior Contributor
    BJ__TN wrote:
    Richie,



    I had a strong gas odor when driving my 54. I too thought it might be the vent tube at the trunk. Then I noticed that it was not as strong when my cowl vent was closed. I couldn't find any leaks, so I decided to check the carb settings. My float level was way too high! I lowered it and have not had the odor since. It may re-occur but for now it is gone.

    Bob



    Bob I have been working on several possible causes today and will continue tomorrow. I will give that idea a try and see what happens. I made some progress today, but haven't finished working yet. Thanks, Richie.
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