Fuel line one-way valve?

[RenaissanceMan]

Hey there-

Helping my father sort out some issues with his '80 Fiat Spider restoration. Noticed there was some sort of one way valve (shape is somewhat similar to a distributor vacuum advance, fwiw) that was on the return line. However, the previous owner had it mounted backwards. Is this valve original, and if so, should it be mounted on the fuel send line or the return line in front of the firewall? Thanks for any insight. We are trying to correct a bunch of errors that the previous owner made while trying to get the car running.

[tima01864]

Fuel injected?

[PhillySpider]

On FI cars there is a funky looking valve in front of the drivers side rear wheel. They clog, mine was causing vacuum in the fuel tank that caused sputtering and stahling until I'd open the gas cap to relieve pressure...If you have one, replace it!

[RRoller123]

+1. This is what it looks like. There is a slightly higher pressure in one direction over the other. Damned if I can remember which way it goes, and it is snowing here now so not going to look. Easy to change, always gets clogged with gunk from the charcoal cannister. It is on the fuel tank to charcoal cannister vent line, which provides makeup air to the fuel tank, and helps maintain an above atmospheric system pressure while allowing vapors to flow both ways.

[MIGHTY 8]

Hi

Had that happen to me as well. Hell of an issue to track down....simple in the end as it is to correct.

I’ve swappwd to Webers from FI. did you replace yours, what suggestions are there to simply toss it?

[RenaissanceMan]

Fuel injected?

No, a single Weber.

[RenaissanceMan]

So we ended up just removing that valve since it seemed redundant, and in the process discovered a cut in one of the fuel lines. Replaced the line and the car is running well again. It's nice when solutions are simple.