Hi all

If my car has 3/4 of a tank or less. I get a whining sound comming from the gas tank after the car is shut down. Its some type of pressure build up. Buy turning the gas cap a little counter clock wise, the pressure vents, a strong smell of gas occurs and the whining stops. strangly, this does not happen in the cool of the morning when i park at work. However, park at home in the afternoon and it happens.

Anyone have this problem and figured it out. I'm guessing some pressure relief system is not working correctly.

I did a search but no helpful results...Thanks

 

Under your car by the fuel tank look for a white color vent valve toward the driver side. This is the vent for your gastank. It may not be venting properly. There not very expensive. Have to get them from the delaer tho.

 

ok...Thanks. Got the part number for those who do a search later. It is # 10033125.

$17.84 from gmpartsdirect.com.

I guess the best way to see if its working is simply try and blow through it.

Thanks a Ton...

 

I looked at the valve and have one on order. Did not try and blow thru it.

I will post after install and let you know.

 

Well...got it installed and still have the whine.

Any ideas. Someone must have delt with this before.

 

maybe the gas cap is not venting properly.the whining may be the release valve working.try running it home w/out the gas cap & see what happens.just a thought.goodluck

 

Our cars have non vented gas caps.

Since u already replaced the fuel tank vent valve, have u made sure the Evap canister side of things is actually purging the excess vapor(pressure) from the tank.

Also a plugged or almost plugged fuel filter could cause the pump to strain as well.

Could try dead heading and seeing if the fuel system holds pressure at the pump when the key is off. If it drops quickly most likely the check valve in the fuel pump is bad.

Most of that doesnt count since u said its after you have driven that car and parked it. check out the evap can/purge valve.

later
Jeremy

 

ok, Thanks I will!

 

The problem has become worse. The pressure is so great that the gas cap becomes damaged. It becomes hard to get off. After that, can't get the gap back on. The threads will not engage and the top of the cap just ratchetts.

Had the small black valve and the relay to the canistar replaced. No differance.

I am at a loss.

 

I'm having this same problem, only I'm sure the whining is the fuel pump, which was just replaced. After about 15 minutes of driving, the pump starts whining. After about 45 minutes of driving, the car stalls at a stop and is very difficult to restart. When is does re-start, the engine does not run normally and chugs, like it is gas-starved. This situation is accompanied by lots of pressure in the tank. My mechanic is at a loss and says he checked the vapor cannister valve. I have searched... does anyone know of other causes, other than the pressure relief valve (gm pn 100333125) or the cannister valve? Please help... first it was the tranny, then a new fuel pump to replace a recently installed one and I'm almost broke...!!

 

I beileve the pressure relief valve at the axle is for sucking air in, not venting it outwards. It keeps a vacuum from forming in the tank. The bad side is that driving your car in deep water (or from a flood) can result in the tank taking a big ole drink of water. Don't ask me how I know. :-(

 

In my tank the line to the canister was plugged in the sending unit, I capped it off and spliced a "T" fitting into the line going to the vent in the back, connected that to the canister

 

we wrapped the muffler to block the heat from boiling the gas in the tank. this was another symptom.... i could hear the gas boiling after the car wouldn't start. it would only bog down, it must have been a vapor lock situation... i've driven around town and on the freeway for about an hours with only the slightest whine from the tank.

 

Hey I am curious did you get this resolved? I have had this issue with my IROC for years and have never figured it out.