today i noticed each time i started up the car i hear very noticible hissing sound from my fuel tank area. After about 1 mins the hissing sound becomes a fain hissing sound.

Car start (hot) and drives normal.

Any idea what may be happening?

 

I had this! It's the evap purge control valve. It sits right behind the back wheel on the fuel tamk side. Has a little plastic pipe coming out that attaches to nothing.

5 mins to attach, $200 from the Dealer, I should've tried ebay first.

BTW I was getting codes 0807, 0903 and 1008

 

It's your fuel pump, it gets quieter when your tank is full.
Perfectly normal.

 

My tank was 85% full when i heard the hissing noise. Each time i started the car today, i hear it and then the noise subdues.

i hope its not the 200 bucks purge vavle

 

is it difficult to replace the purge valve by myself? or did u just reattach that hose and the noise was gone??

 

Would you know a small exhaust leak if you heard it? (Honestly, not trying to be offensive). I know my exhaust is leaking, and I have hissing from the rear of my car too.

 

hmm, i really dont think so because the hissing noise went down by its self after around 1 mins or less while its at same rpm. And i also reved the engine and exhaust tone sounded normal

i hope its just the hose that may have been disconncet. i dont know yet but i ll check in the morning

 

i looked thru the haynes manuel but i did not see a evap purge valve near the fuel tank. I only saw a hose that says goes to the EVAP sollenoid in the engine bay......

 

It's there, near the drivers side wheel I think, with a black plastic splash sheild. I wouldn't sweat it though unless it throws a code.

 

I got the same noise as well. I know that I have a slight hole in my exhaust manifold but that's located in the front. I do hear it after my car's been idling for abit. My car, however runs very well.

 

KRRZ350's right, the purge valve will throw codes and make your CEL come on.

When the engines running it depressurizes the tank (I think) and while you're cruising down the freeway, the purge valve opens to suck all the gas condensate out of the carbon evap canister. If the valve gets stuck open, as mine did, then when you get out of the car you hear the hissing of the air going through the valve. If you open the gas tank and let all the air in, the hissing will stop because you equalized the pressure.

Replacing the valve is very easy. I did it in 5 mins without even getting my hands dirty. 2 bolts, swap, screw, your done.

But if you're not getting an engine light on then it may be something else.

 

ok i checked the noise this morning and i believe its comming from the inside of the fuel tank. Just after around 10 secs of each start ups the hissing noise subdues alot but i still count hear it faintedly. And i my CEL light did not come on.

i hope this hissing is normal..

 

its your fuel pump, leave it be.

 

Try this, turn your key to the on position without starting or turning the engine over.. Listen very carefully for a whining or funny noise from the rear of the car.. If u hear a brief noise it's probaly the fuel pump

 

hmm i just started hearing this noise right now...kinda like under my fuel tank...sounds like how when you turn the key to the on position there's this buzz sound but when car is on the buzzing sound is constant...kinda annoying =/ but i just did what xlr8r says by opening the gas tank and closing it again...the sound is gone now. thanks

 

I thought the hiss was normal. It happens on my 88 as well. Goes away after awhile I believe, but then again I dont pay attention to it after driving.

 

It's your fuel pump and a sign that the fuel pump is tired. New/like-new fuel pumps are very very quiet and never hiss.

 

I thought you get a Hummmmmm when the fuel pump is tired or about to go.

 

yeah, i can hear the same thing you are talking about. when i drive off to the drag strip, you can hear everything alot easier with no interior. I hear exactly what you are talking about and agree with sober. i dont think anything is wrong.

 

I figured nothing was wrong. I would have to agree myself.

 

i think it is your purge control valve .. might be sticky or somthing just not opening up all the way to release presure.. or the absolute pressure sensor mabe not workin right.