How empty is empty?
12-21-2005, 12:22 PM
#1
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How empty is empty?
When my gas guage gets down to 1/8 of a tank, the trip computer is telling me that I have 5 miles left in the tank. That doesn't seem right.
Not wanting to be stranded, I always dutifully fill the tank at this level. The real question is, how low can you go on the guage before you run the tank dry?... And will the trip computer go into negative mile left? Surely at least one of you has run the tank dry, no? Let's hear your story!
--Phil
Not wanting to be stranded, I always dutifully fill the tank at this level. The real question is, how low can you go on the guage before you run the tank dry?... And will the trip computer go into negative mile left? Surely at least one of you has run the tank dry, no? Let's hear your story!
--Phil
12-21-2005, 12:38 PM
#2
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I always test that
With every new car, I run it dry to see what the gague would show. It was really exact science with the B5 and C5 cars, with the B7 and C6 it's less precise. But I can tell you that you are really dry when the needle is half its thickness below the low red mark. In other words, the upper half of the needle is still touching the red mark, the lower half is against the black bground.
At that time, the trip computer has been showing Zero for ~20 miles.
Just make sure that you run out at a safe place. I do it at night on a multi lane local road with lots of parking areas. And carry extra gas with you =)
At that time, the trip computer has been showing Zero for ~20 miles.
Just make sure that you run out at a safe place. I do it at night on a multi lane local road with lots of parking areas. And carry extra gas with you =)
12-21-2005, 04:54 PM
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Re: I always test that
Thanks guys, for your reports. I've hesitated to run the tank dry deliberately because the manual advises against it, and I believe damage can be caused to the emission systems and/or fuel injection.
--Phil
--Phil
12-21-2005, 05:48 PM
#7
Yup, fuel pump usually lives in the tank and is cooled by fuel.
<center><img src="http://www.ukcar.com/features/tech/Engine/injection/Injection/fuel-injection-diagram.gif"></center><p>Also, when injectors snap closed without a cushion of fluid to soften the full force, it tends to damage the needles. I can only imagine this is even more critical with the FSI system.
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12-22-2005, 10:02 AM
#8
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After a period of time, moisture (water) and other junks
settle on the bottom of the fuel tank. If the car is sucking up the last few liters of gas mixed with water and junks, there will be risk that the water will damage the engine, and the junks will clot the fuel filter and starve the engine.
12-22-2005, 12:16 PM
#9
True, crap does collect down there, but not as bad as before. The sealed systems
we use today along with plastic or alloy fuel tanks instead of steel ones, have helped reduce contamination a great deal.
