Bad gas

[Tleg93]

There's a story here in PA about poor fuel quality. I wanted to post this message so that everyone who isn't already aware of the problem is made aware as it can cause significant damage to your fuel delivery system. The story primarily deals with a woman in PA who had recently purchased a new VW turbo and noticed a significant performance loss. Upon consulting a mechanic it was discovered that the car's fuel lines and filter were plugged up with a white gummy substance. The substance starved her fuel pump and ruined it. The total cost of her adventure was $795!!! It was also mentioned that PA has no fuel quality laws (at least for gasoline products) so beware. "Experts" have stated that they are in the process of analyzing the substance and claim they will soon know what it is and the fuel company says it has purged their system of all contaminants.

One of the things mentioned in the article was that, due to nonexistant fuel quality laws in PA, fuel isn't tested for contaminants such as chemicals, residue and bacteria. I had no idea that bacteria could live in gasoline and have some doubts about the truth of that. Any input?

Another thing mentioned in the article was a few steps you cold take to help keep your fuel system clean. I can't remember all of them but one stuck out to me. It said to refuel before the level in the tank drops below a 1/4 tank. I heard this before from a friend's dad (who just passed away, actually ) and I wonder if it's true.

[vrg3]

Huh, so that's one of the reasons gas is so cheap in Pennsylvania.

There are indeed some types of bacteria that can live in your fuel tank. Gasoline's not a friendly environment, but there's usually some moisture in there too. Since the water and fuel don't mix, the bacteria can live in the water.

If gas stations are doing their job right, they periodically stick a probe in the bottom of the storage tank to check for water, and pump it out if there is any.

I'm sorry about your friend's dad.

He was right though. Avoiding running your tank empty does help reduce the amount of moisture that can condense in the tank when the temperature drops at night (since there's less moisture-laden air in the tank). This makes the tank less attractive to bacteria, and also has other bonuses: it reduces the chances that the tank will rust through, it helps keep the fuel pump cool by keeping it submerged in fuel, and it reduces the amount of effort the fuel pump has to exert because the hydrostatic pressure helps it do its job. And, of course, it reduces the chances that you'll be stranded.

[evolutionmovement]

There's actually bacteria that eats oil. I know that's not gasoline, but it's still petroleum product.

Steve

[Tleg93]

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[vrg3]

There are some species of bacteria that actually do metabolize gasoline. What's more, they evolved on their own when prompted by humanity's contempt for Mother Nature!

http://www.abqtrib.com/archives/news02/ ... robe.shtml

[THAWA]

we actually have that oil eating bacteria at work. They use this special chemical to get rid of it, but I dont understand why. unless it's producing some sort of hazardous waste.

[Tleg93]

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[elkaboom]

If I'm not mistaken, the reason you're supposed to refill the tank closer to 1/4 full rather than empty is primarily because of the fuel pump; when the tank is closer to being empty, more fuel tank deposits are agitated and can potentially enter the pump, fuel lines, filter, etc..
I'm not entirely sure if this is accurate, but It does kinda make sense to me. Also, wouldn't less fuel in the tank (like when you're on fumes ) cause te pump to work harder/at reduced efficiency?
I dunno. I just got home from work and I'm a little spacey -also, my valves are chattering so I'm preoccupied...
Anyway, just my 2 cents worth.

[BAC5.2]

You get worse gas mileage the emptier your tank gets.

Try it some time. Measure the fuel economy for a full tank, then drive for 1/4 of a tank and refill. Then drive for 1/2 a tank, and refill. Then drive fore 3/4 of a tank, and refill. Then drive for almost the whole tank, and refill.

You'll notice you get GREAT gas mileage at the beginning of the tank, and then progressively worse mileage as the tank gets less and less full.

[vrg3]

Bob - That makes sense about the particulate deposits... But yeah, the hydrostatic pressure thing is what makes the pump work harder when there's less fuel in the tank.

Phil - Huh. I've never tested that. It doesn't make any sense to me; wouldn't you get better mileage when you're carrying less weight as fuel?

[BAC5.2]

I dunno. I noticed it last summer in my 95. First half of the tank would last forever, I'd see 100 miles out of the first 1/4 tank. Then towards the bottom of the tank, I'd see less and less miles to the 1/4 tanks.

[THAWA]

I think that's something dependant on the tank/pump and stuff. My civic would burn up the first 1/8-1/4 so fast, from then until the last 1/4 it would last forever. My mom's altima is great through the first 1/2 tank then it's eatin that shit up.

[vrg3]

Oh. That's just a function of how most cars' fuel gauges are designed. People like to have the "full tank of gas" feeling for a while after filling up, so the needle falls faster and faster as it falls lower and lower.

I remember reading about Lincoln (I think) having a problem with this. They put a digital gauge in one of their cars to measure the quantity of fuel in the tank with good precision and accuracy. They got all kinds of complaints when they started testing it; customers were like "This morning I filled up on the way to work, and by the time I reached work I no longer had a full tank!"

People are kind of dumb.

[mikec]

I would much rather have a gauge I can trust... Although through flying I've been trained to never trust a gas gauge, judging refills by the odometer is sometimes sketchy.

[legacy92ej22t]

I think it's that after filling the tank it takes awhile for it to register that any fuels been used. I can drive about 40 miles hwy before I notice the needle move off full. After that it seems to fall pretty steady.