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Discussion Starter #1
One of the things that keeps me from total enjoyment of my '73 Spider is the sometimes oily gassy smell to my trunk(boot), that impregnates coats, etc. traveling there. I've taken to carrying travel clothes in a waterproof motorcycle bag. The tank vent has been routed to the filler well, and the gasket on the fuel level sender has been renewed. I'm now convinced that the trunk lid gasket leaks exhaust gasses from negative pressure. Has anyone dealt successfully with this problem? A better gasket? Positive pressure to the trunk? Other thoughts? Thanks, Stinky Scott
 

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Richard Jemison
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Stink

Likely culprit is fuel filler hose and clamps.

Fuel tank vent should be out the bottom of the chassis.

A downward exhaust tip was the solution to exhausr gasses.
 

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I second the filler hose. First time I filled up the tank on my 84 Spider (with the top up), I almost gassed myself out of the car.
I inspected the filler hose and at first glance, it appeared fine. I pulled it off to inspect it and it was in really bad shape.
I replaced it, the filler neck shield and the sending unit gasket.
This link is from IAP that I watched that helped me out.

Video instruction on how to fix a gas smell in the truck of an Alfa Romeo Spider.

Good luck,
Les
 

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Make sure all the hoses are good and tightened correctly. On the vent system, the top hose going into the plastic vapor tank is attached to a metal pipe inside. Withdrawl that pipe and make sure it's not rusted shut (very common). If rusted shut it stops the vent system from working and can create positive pressure that migrates vapor to the trunk.

Check this thread. It explains it with pictures.

http://www.alfabb.com/bb/forums/carburetors-fuel-injection-air-intake/197849-postitive-pressure-fuel-tank.html
 

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Discussion Starter #5
Thank you all for taking time to answer. When I got my Spider two years ago, the fuel tank had corrosion, and after once chasing this unsuccessfully on a motorcycle tank, I replaced the tank with one from IAP. The neck size was not a match for my original, and I had a local sheet metal fabricator weld a correctly sized filler pipe on the tank. I replaced the filler hose, all the clamps, and found loose clamps and cracked hoses on the vapor system. I replaced all of these, cleaned out the steel pipe that projects into one of them, and even found a new old stock vent valve at Alfa Tacoma. I ran new tubing long enough to put the vent valve through the rubber cover of the filler box, into the area under the filler door. Thought this was very clever! My tubing is connected all the way to the engine, and the engine runs great. The only thing from your comments that I have not addressed (in two years. I wish I had read these comments all at once when I bought the car) is the downward curving exhaust pipe. Clarifying further, when I drive the car day to day, I don't notice the trunk smell. I just replaced my rear end with one from Daron @ Vintage Customs in Tacoma (He took it out of his GTV daily driver) and want to put some miles on it prior to Spring road trip. I drove about an hour on Hwy 16 each way, and my stuff in the trunk smelled like the rag bin in the garage. My exhaust is a nice ANSA system, and the tip sticks straight out, and maybe a little up. At speed on the hwy, I'm suspecting the negative pressure area behind the Kamm tail is holding the exhaust gasses, which can migrate into the trunk. Fitting the trunk gasket is a compromise between the lid closing or not. I don't have a small friend who could fit this from inside. I've been thinking about window gasket foam, etc, but a tailpipe curve is something new, even though I've seen them in IAP's catalog. How far down? Does it need to project below the airflow under the car?
 

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I had the Ansa up-swept tailpipe for a while on my '74 for a while. Tremendous amount of exhaust sucked back into the passenger compartment. Ditched that and went with the stock down-turned pipe and that fixed the problem
 
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