Raw fuel smell---FIXED????

[madkaw]

I dealt with a raw fuel smell on my car since the resto last year. My case is unique since I am running a none stock fuel tank on my 71. Since i ran true dual exhaust I retrofitted a CJ-5 gas tank in my Z. I utilized the original vent box and all it's hoses on the jeep tank.

The raw fuel smell appears on hard left turns where the gas sloshes towards the fuel door. I never saw any indication of leakage anywhere, so I assumed this is a vapor leak-go figure with the Z vent box. I can stick my head under the car around the tank and smell a slight wiff of fuel just sitting there in the garage, but see nothing.

I decided if I could slightly pressurize the system i could identify an vapor leak. I decided to use the crankcase vapor line in the engine compartment as a place to pressururize the system. I set up a blow gun with a seperate regulator so I could just barely push air thru the system. WARNING-don't put too much air into this closed system.

With the air just trickling thru the system, I could hear the air escaping and I found the leak exactly by spraying down all the lines with some soapy water. The bubbles verified that I had a pin hole in my filler neck(that i made) and fuel vapors were being forced right into the interior.

Next i will be making a some kind of one way flapper door inside my filler neck to keep any fuel from sloshing up there in the first place.

[Bruce Palmer]

Nice piece of detective work. That there's "mechanican" folks.

[Walter Moore]

Good job Steve.

[tlorber]

Good fix.

I just recently found a source of gas fumes as well. The recess where the gas cap is was caulked to the rear quarter panel at manufacture. There were two pin holes in this caulking (I had a friend spray some alcohol in the area while I looked inside and noticed the liquid running down inside the quarter panel). I recaulked this from outside and inside, and then spray painted over it. I have yet to see if this has completely resolved my problem, but it has certainly reduced it

[ZCurves]

Steve - I have to say that this has indeed saved me a bunch of time. I will attempt your technique on my own Z to see if I can track down my own fuel odor. Thanks for the tip.

[madkaw]

I want to reiterate about the air pressure. It takes hardly a trickle of air to do this---so be cautious or you will have new leaks;)

[Oiluj]

I'm impressed!

[madkaw]

Just an update. Now that i am actually driving the Z again, I can verify that the raw fuel smell is gone. It is obvious thta the pin hole i found was the culprit. How nice it is to throw the car into a corner and not have to worrry about fuel being in the wrong place.