[Colo_Mustang]

I have a 1965 Mustang that expels gas fumes after it has been driven. The fumes get so bad I have to leave the garage open for several hours to air it out.

I have replaced the intake manifold and carb with an Edelbrock Performer manifold and a 600cfm carb and new fuel lines.
My car still smells like it is flooded out after I drive it and the garage fills up with gas fumes. The only thing I have not replaced is the fuel pump. Any ideas

[Veronica]

Hello. I think that the first thing I would do is look for leaks. Fumes as serious as what you describe would almost have to involve visible amounts of fuel. If the fumes dissipate after the car has been shut off, then you can rule out the gas tank and the long line that goes from the tank to the fuel pump, since it would leak all the time from there.

[Aloha66]

I had a similiar situation with my '66 and I think that my problem was related to the engine temperature - my engine was running way too hot and I think that the high engine heat was causing the fuel in the carb to evaporate creating the fumes.

I replaced the faulty temperature sending unit and bad 195 degree thermostat and now I dont have a fume problem.

[sooner65]

Had a similar problem with my '65. Turned out the accelerator pump on the carb was leaking onto the intake manifold and pooling on the manifold. It was hard to find the leak becuase it wouldn't leak unless you were pumping the accelerator. Most of it would evaporate when it was running, but sometimes it would accumulate enough that the fumes were pretty strong. Simple carb kit would do the trick if that's your source.

This may be one for Mythbusters, but my Grandpa told me that back in the day, dealerships or even car owners would have cars in their garage with these types of problems and when the coke machine or fridge would kick on overnight when the garage was closed up and there would be an arch/spark that would trigger an explosion in the garage. Seems like there would have to be a lot of gas in a small garage, but that's the story I was told...

[The Greek]

Sounds to me that the carb's idle circuit is too rich. Some carbs allow for adjustment of this circuit by altering the idle fuel restriction. (Making the restriction smaller.) A choke that isn't opening completely can also create the problem. Are the spark plugs black and sooty? Are the idle mixture screws almost adjusted all of the way out?

[Colo_Mustang]

There is no fuel leaking from the gas tank, I put in a new gas tank, fittings and line. The Carb is brand new Edelbrock 600cfm with performer manifold.
I replace the old carb and manifold due to this problem. Even with new carb and manifold the problem persisted.
I ended up taking it to a mechanic and he checks my Carb install, he fine tuned the carb and says everything is operating perfect. He even checked to make sure the float was not stuck.

The car is not over heating, I have checked to see if the gas was boiling in the carb after I turn off the car. A friend of mine suggested maybe pressure was building up in the gas tank, but everything there is factory spec (Tank, Float, Fuel Neck/rubber hose and gas cap).

There isn’t any fuel leaking on the floor, it is straight fumes from the engine?