fuel odor

[Pete Munroe]

Kristen,

If you have a mechanical fuel pump, look at the bottom of the unit...if it is shiny clean, it may be leaking.

For years my 67' 327" Corvette had a awfull fuel smell...could never find it.

Finally, I ended up under the car with the engine hot and running and the crimp that hold the lower housing on a GM style pump was seeping like crazy all 360 degrees.

It only leaked obviously when it was running...it would evaporate almost immediately after shutting off and I wouldn't notice it was/had just been wet.

The pump was very clean while the rest of the front of the engine was standard oily road film...anything clean is suspicious.

Replaced the pump, no problem since...that was 10 years ago.

On another note, I did not know ethanol was more volatile than gasoline, don't think it is. But the refiners can vary the "Reid Vapor Pressure", (rate of evaporation at a given temperature) of the gas stock to suit the time of year.

Summer, higher vapor pressure to avoid vapor locking due to heat, winter, lower vapor pressure to help starting and general runability on a cold engine.

The "Reid Vapor Pressure" is critical in fuel used in aviation, trying to use MoGas, car fuel, can lead to problems in some light planes as the tendency to vapor lock due to extreme changes in altitude.

Some of the a/c systems tolerate the vapor locking tendency, some not so good.

Fortunately, its not likely to get your Cobra 5000 feet straight up to see if you have a problem though.

Pete