Howling from fuel vent

[Westwood]

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I have a 2000 Boxster which has a howling noise from the fuel venting system. The PCA website has a few other people complaining about the same problem, but their advice is to see your dealer. Has anyone here figured out exactly what solenoid, vent, etc. is causing this? and how to cure it?

Thanks,

Roger

[PTEC]

I've seen the same situation and what fixed it was the fresh air shut off valve. This valve is only used during refueling and is part of the ORVR system. On the car I saw, when the tank would vent it would cause a howling sound which would stop if you put your hand over the vent for the ORVR system. From the way I understand the system that valve should only be open during refueling, if its partly open during the tank vent process, you'll get a howling sound. If the sound is coming from the ORVR vent line then its pretty much the only valve that could be causing it.

EDIT: It looks like its called the carbon control valve, part number 996.605.213.01.

When the car is doing it, undo the gas cap and stick your finger in the filler neck and activate the ORVR switch. If you hear a click and the howling stops, you probably need this valve.

Edited September 16, 2005 by PTEC

[Westwood]

Thanks,

Today I actually got frustrated and put a piece of tape over the vent hole behind the fuel door (when open) and no more noise. I was sure it was some kind of valve that was not closing properly.

Roger

[rdragon]

westwood - can you describe when you get this noise? i am experiencing some noise as well and never knew how to describe it but it does sound like howling (a bit).

[PTEC]

westwood - can you describe when you get this noise?  i am experiencing some noise as well and never knew how to describe it but it does sound like howling (a bit).

<{POST_SNAPBACK}>

The noise i ran into sounded like when you blow across the neck of a bottle just right and you get a howling sound. In my case the noise was most noticeable after a drive cycle.

[rdragon]

ptec - what do you mean after a drive cycle? thanks.

[PTEC]

ptec - what do you mean after a drive cycle?  thanks.

<{POST_SNAPBACK}>

Basically after allowing the car to come up to temp. The DME has to see certain parameters met in order for it to under go all of its tests like oxygen sensing regulation, tank venting, secondary air injection and the like. On the car i had, I could let it sit there forever and the noise would never happen. However, if I took it out for a quick spin I would notice the noise almost immediately upon return if I left the car idling.

[rdragon]

i see. thanks for info.

i seem to get my "howling" noise when driving in 2nd or 3rd gear intermittently...

[Westwood]

I just realized that I did not follow up. The carbon control valve is what needed to be replaced. Not a bad job, I went through the wheel well, but now wonder if you could pop out the headlight and get at it. It did take care of the howl. Funny, when I removed the old one it came out in two pieces. Wonder if it was cracked and I broke it removing it?

Thanks for all the help guys, and let's hope this helps someone else fix theirs.

Roger