gta ta

My GTA sounds like a cow or a fog horn every 15 minutes.

Every 15 minutes there is a deep vibration that sounds like a cow's moo or a fog horn. It comes from the fuel tank area. I notice the gas cap has pressure behind it when I take it off. I think the tank is not venting. It only does this when it is driven a distance.

Anybody know what is wrong????

85transamtpi

Mine kinda makes some sound from the back that I guess could be described as a whine or moo. For me its the fuel pump, fill 'er up and the sound goes away (only happens with less than 1/4 tank)

-peace

Azure

I'm so sorry if I come off as an as#hole here, buy when I read that post ("...that sounds like a cow's moo...") I literally laughed until I cried...haha...."MoooooO!" lol lol lol!


...sorry. =(

gta ta

I thought people might get a kick out my subject...

This noise is only made when car is not running and is parked. When It first started I thought maybe the horn or fuel pump so I disconected the battery. It still makes the sound with battery disconnected. It is not the fuel pump I know what it sounds like. This sound is real loud!

85transamtpi

interesting...

I didnt think I would call it a cow sound. That loud huh? you thought it was the horn?!? The car has to be turned off and parked?

Now you got me thinking...

too bad I cant come up with anything

I'd like to know what it is when you figure it out. Anyone else got any ideas?

BuddyLeeX

mine sometiem ssoudns liek a frog

Corry

Has Tom Green been near your car recently? lol! My guess would be some sort of venting issue, pressure going out the right size/shape hole can make some odd noises, metal under changing pressures can also make some odd noises (i.e. you always see the submarine movies where the sub sinks to deep levels and you hear that noise? That would be an extremily exagerated (sp?) case of the tank itself making the noise)
Post the solution when you find it, and everyone start watching Tom Green to see if you see a trans am mooing at people
Corry

No4NJunk

your getting vapor lock..... or a case of it anyway. There is a ventilator cap attached to the bottom side of the drivers side back seat tub. Its black and white and it faces the rear differential. They get clogged up sometimes so you might want to check it out. I'm pretty sure your car doesn't have one but if you have a carbon canister tear it out. The filters can get real dirty and have the same effect.

gta ta

Now we are getting some where. It is related to the Gas tank because if I open the gas cap and vent it then it will not make the noise anymore till driven again. It comes from the region of the gas tank. every 15 minutes. You can set your clock by it. But this only happens if it is driven for a distance. WHen I had it on a friends rack I notice some kind of filter vent on the end of a hose from the tank. I have thought that might be pluged up with dirt.

Yes I have a canister! SO I sould disconnect it? WHat about all the sensors on it? Never thought about that...

Yes it is loud enough to hear inside a two story house every 15 minutes all night long.

Flash84Z28

I think your t/a is mutating into a cow! I'm LMAO at the sight of your neighbors' lights comming on every fifteen minutes at 2:30 in the morning thinking you bought a cow or something.

I'm pretty sure you canno't just disconnect the the canister, you will probubly end up with a vacume leak. Although I do recommend dumping the canister unless you have very picky emmisions.

-Matt

No4NJunk

Tear the canister out!! there aren't any sensors on it....at least there wasn't any on mine. Plug the vacuum line with a screw so you won't have a leak. As for the Ventilator cap. Take it off...remove the innards, clean everything then put it back in. I left the springs and valves out of my cap and it helped everything but i guess you can leave the stuff in.

Patrick007

I thought that if you removed that canister you would get some NASTY fuel smells. Also.. what would you do with the other lines running from the canister. The vacuum line is easy enough to plug but what about the line that goes to tank? vent it out the back or what.... thnx guys

Patrick DeGrosse Jr.

Flash84Z28

I think most of that nasty smell is taken out by the cat. I have never had a canister on my car (removed when I bought it), but I think you can just plug the fuel return line (goes to tank) with a screw, or cap it off at the tank.

-Matt

Patrick007

So that isn't the main tank vent? I though the tank vented right there.. is there another place? or is that the hose facing the diff that you were talking about? thnx

Patrick DeGrosse Jr.

gta ta

Yes I guess they are not sensors but some kind of controls to open and close the canister. there are two sets of wires going to the canister and two electral connectors on top of the canister. So I can just on plug them and let them hang then?

WHat is the vent cap? You mean the gas cap? Should I get a vented cap because mine is not vented... Mooing stops when I open gas cap...

Thanks for the replies! You guys are great...

No4NJunk

No...not a vented gas cap..a ventilator cap. Just as I said it is underneath the car. Jack the rear up or crawl under there and you will see a bunch of lines on the drivers side on the back of the rear seat tub. Next to all the brake lines is a ventilator cap. Its about as big as a camera film container. Its got a black base and a White cap on it. Take it off and clean it or remove the Valves and springs on the inside so it will always be open. This lets fresh air into the tank while the vapors go through another line to the carbon canister to be vented out. Follow the line that goes from the canister to the back of your car. It will be a metal line all the way back until it reaches near the ventilator cap then it turns rubber and goes up to the top of the tank. Where it turns rubber, unhook it and stick a Specter clear fuel filter on it...this keeps bugs and **** from getting inside your tank. This will let the gas vapors vent from behind the car instead of under the hood. Its relatively simple..really ..As for the canister, chuck it. Unplug the wires and get rid of that thing. This should solve all of your problems. And DON'T plug up the fuel return line. This will cause flooding in some cases among other problems. There is nothing wrong with the return line...leave it alone. Hope this helps.

gta ta

Wow Thanks for the great reply. You have told me every thing I need to know.

Should my gas cap be vented??? It is not

RB83L69

gta is partly right, the sound is made by that valve he is referring to. It is just inboard of the left rear swaybar end link mount. My car used to do that although I would describe the sound as being more like the car blowing its nose.

Just get a new one, they're available at the dealer, don't tear up your car's gas tank vent system. That's not a really bright idea.

Leave your canister alone.

Your gas tank is supposed to be pressurized. In fact, many (if not all) newer cars will set a trouble code if the gas cap is not on properly, since it is an emissions issue.

gta ta

Okay Its not mooing it's blowing its nose! Best description yet. Is the gas cap supposed to be vented?

No4NJunk

I just sent you an email on this but no its not supposed to be vented.

TheIgnitious

Since I've replaced my gas tank I've noticed this noise... I think I found the ventilator cap you all are talking about.. It is about fuel filter size in width, but only about an inch tall with a big hole cut out on the end? It looks kinda like the inside of a speaker. Anyways when I replaced gas tank I just stuck old one on, but it literally vibrates my car. Pics anyone? (Old CFI lines were cut, so all my stuff moved around)

L98GTA87

iTrader: (1)

Definitely brought this thread back from the dead!

Not sure what's the cause of the vibration. Hopefully someone with better knowledge on this issue will chime in and give you some insight.