deacon17

Whenever the car is turned off after being driven even only a few miles, I get excessive whine from the gas tank that goes away if I unscrew the fuel cap to let the built up gas out. My question is, is this indicative of any kind of problem, such as a failing fuel pump? I haven't ever heard of anyone having this problem and appreciate any opinions on the matter as I have had a few sporadic problems with my fuel system (occasional stalling, hard starting, etc.).

sunbitz

Well, we know it's not likely to be fuel that is leaking, because fuel does not whine.
Air/vapors would be what I consider to whine.

So I doubt it would be the fuel pump. Unless there is vapor in there as well.

I'm gonna throw a wild guess here and say it may be your gas cap.
Perhaps it was threaded wrong the last time you filled the car with gas. If not....

Can you pinpoint where the whine is coming from??

Do you smell any vapors in or around the car after driving it??

Could it be you drilled a hole near the gas tank area and the drill bit tapped into the gas tank??

Ken88GTA

I just replaced my fuel pump and my car still makes that noise (no, that's not why I replaced it) so I don't think it's an indication of a failing pump. Most likely its either the gas cap not sealing or I did notice a white plastic thingy attached to the tank vent line, maybe it's bad?

Ken

Yarnboy

I've had the same problem for a long long time. I can hear it when I am about to run out of gas too..It sounds like the fuel pump sucking in air..but I'm not sure why it would be when there is gas in there. It also goes away if you unplug the charcoal canister. Try it! If anyone ever solves this mystery, I'd like to hear about it.

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deacon17

That's weird, at least now I know I'm not the only one dealing with it. Checked my cap and filler neck and didn't see any visible problems with either--no cracks, dents, etc. And it occurs at any time after driving, whether the tank is empty or full. Even if I unscrew the cap and let the pressure out, it builds back up and starts again in a minute or so.

sunbitz

Deacon...
Have you been able to pinpoint where the whine is coming from?

And I'n not talking about the rear of the car near the gas tanks type of thing.

Does anyone know if there is a vent system in the gas/fuel systems for vapors to vent?

I'm kinda thinking on the lines of there might be a vent hole either in the gas cap or somewhere for fumes to vent and some crap has plugged that hole causing it to whine/whistle.

This is truly a strange problem.
I've never heard of such a thing.

I can't wait to see what it could be.

I'm staying tuned.

RB83L69

I'll tell you excactly what it is. BTDT.

There is a little plastic pressure relief valve in the rear end tunnel, just inboard of the left wheel, where the fuel lines come down from the tank and make their bend to go horizontal through the driveshaft tunnel. That plastic valve is bad. My car made a noise like a goose honking or somebody blowing their nose; it would usually do it in little short blasts a few seconds long each, maybe 5 or 10 times depending on how warm the car was. I had to drive the car on a hot day, drive it into the garage and jump out and jack it up and crawl under there, and wait for it to do it, before I finally found it. It did it for I guess 3 or 4 years before it finally drove me crazy enough to find it.

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deacon17

Thanks for the tips. I will try to pinpoint that location and make sure that's it as soon as I get it out on the road again and drive it enough to build up some pressure in fuel system. Will keep you updated. . .

BenDoe

Is it a whine like a pressure leak, or a while like the pump is still running. To find out, disconect the battery and see if it goes away. I had this problem when i got my car, and it turned out that the oil pressure sending unit was bad. It is a sensor that will turn the fuel pump off when the oil pressure drops(in case of an accident, or no oil). The owner of the car before me didn't fix this problem and ended up running the engine out of oil and seizing the engine... that sucks. The sensor is near the filter, up and to the front of the car. You can get to it from under, or above the car(if you don't have headers).

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sunbitz

RB83L69 & Deacon

RB83L69 is most possibly correct on this one. I checked through my Chilton manual and it says the same thing.
Worth taking the time and searching for it.