Howling noise from fuel vent

[Westwood]

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

[jpboxster]

Hello,

I have the same question and problem. It comes from the vent hole underneath the gas/fuel filler lid. Does anybody know, if that's normal or how to fix it?

Thanks!

[kikfm]

If you open the fuel filler compartment you will notice three vent holes to the right of the gas cap. One of those vents is catching air at certain speeds and causing the howling noise. If you get a little rubber hose to extend the vent that is causing the noise it will stop.

[spongebob]

I solved my noise by putting a piece of a regular car washing sponge in the hole.
It still makes ventilation possible but it breakes the airflow at the end of the hose.
I have heared about several people that have changed solenoids and hoses without sucess. This is an easier way to go.
As I had this noise just holding the engine on a certain rpm in neutral it cant be wind noise.

[Dar01]

Thanks for the tip spongebob!....I could not figure out this noise, it would happen when I would be steadily moving along.....let off the gas....noise goes away.....step on the gas, noise goes away....keep it steady.......HOWLING noise that I thought was the tranny!

Little piece of sponge and problem gone!!!!!!

Whew!....

Thanks to everyone who comes here and puts their experiences in writing....

[CA_Boxster]

Originally Posted by spongebob

I solved my noise by putting a piece of a regular car washing sponge in the hole.
It still makes ventilation possible but it breakes the airflow at the end of the hose.
I have heared about several people that have changed solenoids and hoses without sucess. This is an easier way to go.
As I had this noise just holding the engine on a certain rpm in neutral it cant be wind noise.

I was able to repeat it at varying RPM and engine speeds, but never really tried it in neutral. I reached the same solution. For me it was any time the car got level at a constant speed. Lift or lower the nose and it stops, but any constant speed caught the air just right.

The dealer's guess was that some vent valve was stuck open but it was going to be a long, expensive process of elimination to know. The little piece of rubber I stuck in there cost a lot less...

The real question: How close to crazy did this noise drive all of you and how long did it take you figure out it was coming from the freakin gas filler? My answer: Pretty damn close and way too long. The only thing worse than listening to that noise was knowing it was going to happen.

[Westwood]

Since I started this thread a long time (and three Porsche's later) ago I thought it appropriate that I pass along the final fix. Mine was a part, as I recall, called the Carbon Control Valve. when I pulled the inner fender liner loose it was way up there and was not very easy to get too. But replacing it did fix the problem. And as it turned out when I pulled it out it was cracked and that was probably why it was leaking air at the certain RPM and causing the howl.

I think Renntech was where I found the fix.

And yes, it drove me NUTS!

Roger

[CA_Boxster]

That's probably the valve the dealer mentioned to me.

[CenterIsl]

I am so damned grateful for this forum! I just yesterday bought an 03 Boxster S (Speed Yellow) and was out today for a long holiday drive with my wife (who, incidentally, LOVES the yellow) and we got that noise. She never hears noises, but this one she asked about. And a quick search and...damn, that just has to be the problem (I simply searched on "howl" and found this thread! I have EXACTLY the same symptoms). I'm going to sleep a lot better tonight...

[maxargonaut]

After lots of head scratching and three failed attempts by a local Porsche garage to diagnose this, I took it to a dealer and they replaced the "Fuel Tank Vent Valve" and valve housing and the problem went away. I was also having trouble filling the tank all the way (it would shut off after 3/4 of the tank or so, after which I had to baby the gas in until the tank was full). This took care of that too.

I tried the "put some sponge in the hole" fix, but (a) it made filling the tank impossible unless I took the sponge out first, and (b) under heavy accelleration the car hitched like it was running out of gas. I only ran into that latter problem once before I decided to live with the noise instead.

This fix cost me $800, but it's a great relief to have it taken care of finally.