Vacuum sound

[feddomw]

Searching didn't give me any results, so here goes:
on my current 100, when I remove the gas cap to fill 'er up, I always get a strong and long vacuum. So, air rushing in to the tank, as if it is sealed ander underpressurised.

I can't remember my previous 100 having this, just occasionally. Engine runs great, FWIW, even when I'm running on fumes. But do we all have this? Is this something I need to chase down?

 

[Trunk Monkey]

Some pressure in fuel tank OK?

 

[feddomw]

Thanks! I didn't search for "pressure" because I thought it was the inverse: vacuum in the tank, not overpressure.

 

[Julian Stead]

Mine is like that, I think it is normal. Have you got a charcoal filter that could be blocked, I dont have one fitted so it might be different.

 

[feddomw]

No clue. My 100 is GCC spec and I don't think they are big on emissions, so I'll leave it for now. Engine runs fine, and judging by the comments on prices for a new charcoal canister, I'll skip it.

 

[Trunk Monkey]

I just searched for "gas cap", title, 100 section.

 

[feddomw]

And I just walked out to my car and discovered that the big black plastic thing next to my battery in the engine bay (which I had been wondering what is was for) is my Charcoal Canister housing with all the assorted tubing going in and out....

I have OEM sub-tank, guess they can't place it in the rear with that installed. At least it will be easy to work on if needs be.....

 

[2001LC]

Normal to have some air sound "hiss" when removing gas cap, more so on hot days. No hiss and rough running (lean fuel mixture) is often bad gas cap.