Is this a vented gas cap?

[BigB]

Hi All,

Just wondering if this is a vented gas cap? I need to run one for my fitech efi.

Thanks.

 

[Lawndart]

It looks like one, however I have had to punch a couple like that to get them to vent properly. Blow on it an see.

 

[broncnaz]

Yes its vented. Most caps are. Some vent both outward and inwards but most only vent inward. Vented caps are usually considered to vent inward so you dont create a vaccum on the tank. You really dont want them vented to release vapors to the air that can be bad especailly if you park in a garage.

 

[BigB]

Thanks for the replies guys!

Broncnaz: Does it vent off internally and suck fresh air back down the vent line from the filler neck? That makes sense.

 

[BigB]

It looks like one, however I have had to punch a couple like that to get them to vent properly. Blow on it an see.

Did you punch it with your fist?;D

What do I do to make this work as mine is not venting. There was a massive vacuum on the tank. I tried blowing on it and got no joy.

 

[Lawndart]

However they are suppose to work, none of mine did. On my '67 F100 the tank would not vent and vapor lock. Take the cap off and you could hear the air rush in.
I took a punch and attacked the inside center piece. After a good hit, a fine spring came out behind the center portion. All well now. I did the same for the two new "vented" caps I purchased for my Bronco (all came from LMC, but a common manufacturer).

 

[BigB]

However they are suppose to work, none of mine did. On my '67 F100 the tank would not vent and vapor lock. Take the cap off and you could hear the air rush in.
I took a punch and attacked the inside center piece. After a good hit, a fine spring came out behind the center portion. All well now. I did the same for the two new "vented" caps I purchased for my Bronco (all came from LMC, but a common manufacturer).

Thanks mate, I'll give it a whirl.

 

[Lawndart]

Here is a crappy pic, but may assist. After I prick punched it, I could see a portion of a spring. Took a pair of needle nose pliers and removed it.

Damn, look at that rubber on a lest than a year old cap....

 

[BigB]

Nice one, cheers!

 

[BigB]

Gave it a quick hit with the punch and now I get air movement.

Thanks again!