Howling from the fuel tank area....

r1de23 · 04-21-2010, 12:47 PM

I started to hear an annoying howling noise coming from the fuel tank/fuel cap area. Now the only thing i can think it could be would be the fuel pump. any ideas?

Wayne 962 · Wayne 962's Garage

When was this, and what year is your car? If the tank vent system is not working properly, then you can get a vacuum build up in the tank and then leakage around seals. That might be a "howling". Or, it might be the fuel pump.

-Wayne

Pacific996 · 04-24-2010, 01:27 AM

Have you tried listening with the trunk open? I was thinking it might be in the a/c area that's right next to that area.

r1de23 · 04-27-2010, 06:40 AM

so i replaced the fuel pump in the mean time. and the noise is still there.

I noticed that the howling only occurs when i barely step on the gas pedal, then as soon as i left off it disappears. The noise also goes away after i step on the gas pedal beyond the "barely step-on" point.

Note: the A/C is never on when this occurs.

Is there some sort of pressurization system in the gas tank? what are all the components forward of the battery besides the fuel pump and radiators?

Jamikest · Jamikest's Garage

Remove the gas cap- is the noise still present?

Purge valve *could* pull a vacuum if there were multiple malfunctions (IE charcoal canister) just not likely...

Are you sure its in the tank area? Brake booster is also vacuum supplied on the drivers side.

r1de23 · 05-15-2010, 07:49 AM

noise it still present when i open the fuel tank. i found out where it is coming from... the hole behind the fuel door, when i put my finger over it, the howling stops.

where does this hole lead to?

r1de23 · 05-15-2010, 11:28 AM

Update: i looked up the part # on the clip in the picture and it lead me to the vent line for the carbon canister... any ideas?

Menmojo · Menmojo's Garage

I am having the same problem with my wife's 2001 boxster. I took the car to the dealer and the computer registered an error code for the carbon canister. It seems to be identical to your diagnosis. Have you come to a conclusion? I'm still looking for a solution and any ideas would be helpful.

Wayne 962 · Wayne 962's Garage

There is a solenoid that is activated in the engine compartment for a vent line to the tank / carbon canister. I'm not sure if a failure of this component would cause this noise, but it seems like it would be a likely culprit. The valve is electronically controlled and basically connects the tank to the intake manifold and pulls a vacuum on it when the engine is running. I'm not sure when this valve opens though. I think this and the fuel tank pressure sensor are the only two electronic components associated with the system?

-Wayne

murfboston · 07-20-2010, 10:21 AM

Hi guys,

I'm new to the forum, but have the same issue with my 2001 cab carrera. It seems like when there is a demand for gas the vacuum is created and makes this noise. I can have the car parked and turn the AC way up and the vacuum noise will start. If I put my finger over the hole the noise stops.

Did replacing the valves fix the problem, or is it the pressure sensor in the tank. Thanks for any insight.

Paul

sandersd · 07-23-2010, 12:35 PM

Check for wolves (or coyotes depending on the pitch of the howling). Sometimes they hide under the wheelwell behind the tire. I've even seen them in the trunk before although I never could figure out how they got in there...

murfboston · 07-26-2010, 07:32 AM

had no idea your mother hid in trunks

R2 Racing · R2 Racing's Garage

There are two valves under the right front fender that are the culprit of this noise. they open and close for tank venting and are not shutting off. Replace them and the noise will go away

murfboston · 07-30-2010, 05:42 AM

OK, thanks. I just wanted to make sure the pressure sensor in the tank wasn't triggering the valve to stay open.

calh4289 · 02-03-2013, 05:03 PM

I know that this is an old thread, but I was wondering if the noise was resolved and what was the fix?

txhokie4life · txhokie4life's Garage

Had it on a boxster -- replaced the purge valve underneath the intake and it went away.

Actually since getting under the intake was a PITA -- I bypassed the complete
line assembly from the lower front engine compartment to the other end of the valve
connection.

It's been about 3 years so my exact details are fuzzy, but no problems since.

I had done all the front of the car stuff to no avail before trying the purge valve.

Mike