What's the vent inside our gas filler door?

[jefla]

I've a 2000 base w/ 44k mi.

What is the deal on the vent inside our gas filler door, toward the front of the car. Mine occassionaly blows enough air to be audible from the cabin while driving. When its "blowing" I can make it stop by lifting off the throttle.

I recently posted a topic about a whistling sound (http://www.renntech.org/forums/index.php?showtopic=15582), and yesterday finally figured out that this vent is the source of the sound.

jef

[kbull88]

Hi Jef,

I have a 2000 C2 and I get the same kind of noise. But it doesn't occur until I exceed +100 mph. It sounds like a buzzer or a card stuck in the radiator fans. How did you discover it was vent in the gas door? Where is exactly are you talking about in the gas compartment?

Have you fixed it?

Please let me know so I can check it out on my car too.

Thanks, Han

[Loren]

Many times a whistling sound heard at speed is a misalignment of the front bumper cover and the front hood.

To find out for sure put a piece of tape across the hood and bumper seam and see if it still happens.

[kabel]

I think the "vent" your referring to is actually just a drain hole for any gas that may happen to spill over during fueling...

[jefla]

Here's my fuel filler; the vent is at the top right and drain hole at bottom center. Revved to about 2500 rpm the vent definitley whistles (darn near loudly) due to blowing or sucking air (sorry about mising this detail, I was so excited when I finally ID'd the source of the noise I didn't stop to make that note). When whistling, if you cover the vent it stops. Also, as noted in the earlier post on this if you change engine speed it will stop. I think it's part of the evap purge system. Also, my mpg seems to have fallen off considerably.

Re Han's question about how I nailed this down, my wife hung her ear waaaay out the car and we at first figured out it was coming from the right front, then inside the fuel filler.

PS I finally located an earlier applicable post, which said the noise is caused by a bad (unidentified) valve in the fuel system.

Definitely looking forward to your collective replies.

Jef

[Highlander]

I think the "vent" your referring to is actually just a drain hole for any gas that may happen to spill over during fueling...

Yup, that's exactly what it's for.

[jefla]

I'm not inquiring abou the drain hole in the center lower portion of the filler (see pic), but the other hole, which I beleive is a vent, at the top left.

[kabel]

ah! sorry Jef. Pictures always clear things up, I never noticed that other vent.

[jefla]

I finally went to the PCA tech website, and found part of an answer to my dilema. The question presented was: "awhile back I posted a message on a howling sound at certain RPM's. I finally found the source...a vent in the fuel filler cavity. This vent (the one facing the front of car) appears to be part of the emmisions control system and at about 3000 RPM has enough suction to howl fairly loud. I put tape over the vent and the sound went away. The car seems to run better (vacuum leak?) Is this normal? If not, what should I tell the dealer to fix? I have had the car in twice and they didn't get as far as I did in finding the source.

PCA's reply was: "The system you are talking about is ORVR. This system recover the vapors let out of you gas tank when you fill up your car. It only works when you fill up your car and insert the nozzle into the filler neck. When you take off your cap, push in the flap and you should hear a click for the system to start. You might have a problem with the system, if you have vacuum in that hose when the car is running, you have an issue and should go to a dealer. Peter Smith - PCA WebSite - 9/17/2002

First, my thanks to PCA.

So, it appears that my mystery noise is a vaccuum leak in the ORVR, which could explain why my mileage,and possible performance, has dropped. Given this info, does anyone have experience w/ the ORVR or can you direct me to a schematic of the system? BTW, I had a similar experience w/ my mechanic as did the PCA poster: my mechanic thought the sound was the cooling fan ......

Jef

[mrgylex]

I have the whistling noise when my car is idling, very loud...had me completely lost as to what was the issue..i have very rough idling and loud exhaust note..I really hope this fixes the issue....What was your resolution to this issue, took it to the dealer?..please help