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From the manual: it says that "If the range is below 50 km refuel the car, otherwise the engines functions are not assured, and damage may occur".

Sound very ominous. Engine damage? Anyone know why this is written like that?

Jonas
 

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well most petrol tanks tend to build a bit of "Sludge" in the bottom of them, as I am led to believe, and putting that through your engine can't be good.

Besides which, the computer will probably never be 100% accurate, so 50km range could mean 40 or 30...
 

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My personal " best " is range=21km!
At that point I only managed to squeeze in 63 L in the tank!
The fuel measuring system is calibrated well on the safe side IMO! cherrsagai
 

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cidair said:
My personal " best " is range=21km!
At that point I only managed to squeeze in 63 L in the tank!
The fuel measuring system is calibrated well on the safe side IMO! cherrsagai
well actually, judging from the fuel consumption of the M5 we've seen to date, it might have been true... :eek:
 

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You guys are lucky! If I get past 41 miles to empty, it starts dropping at a fast rate to the 20s, and the car starts to misfire and trip the SES light. I have learned to take the E39's fuel warning light VERY seriously, because it means I am literally about to run out...
 

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Nisse said:
From the manual: it says that "If the range is below 50 km refuel the car, otherwise the engines functions are not assured, and damage may occur".

Sound very ominous. Engine damage? Anyone know why this is written like that?

Jonas
Here's a theory....when the tank goes dry, the in-tank pump may continue to run open-loop as the fuel itself is needed for lubrication and cooling. Hence, the pump burns up and may even contaminate the system.
 

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There is also the rumor that if you run the car empty you will have to go to the dealer to have the fuel system purged to get air out of the line, otherwise the engine won't run properly. Of course, I have never been able to prove that myself, the couple of times I have run out of gas, a simple fillup fixed the problem.
 

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Nisse said:
From the manual: it says that "If the range is below 50 km refuel the car, otherwise the engines functions are not assured, and damage may occur".

Sound very ominous. Engine damage? Anyone know why this is written like that?

Jonas
Gasoline is heavier than water. When the tank gets this low, there is a good chance that more water will go through the fuel line in the last gallons. Also, keeping a tank low adds to condensation and corrosion of the exposed surfaces and further contamination of the fuel. Keeping the tank full helps the engine get a better overall quality of gasoline and keeps the tank itself in better shape (unless we have a non-corrosive tank?)
 

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Digi said:
Gasoline is heavier than water. When the tank gets this low, there is a good chance that more water will go through the fuel line in the last gallons. Also, keeping a tank low adds to condensation and corrosion of the exposed surfaces and further contamination of the fuel. Keeping the tank full helps the engine get a better overall quality of gasoline and keeps the tank itself in better shape (unless we have a non-corrosive tank?)
Bearing in mind that I have to refuel my car every 2-3 days (so far my worst range on one tank is 92 miles. Ouch!!) I tend to run it pretty dry. So far I've discovered that with --- showing as the range I can get at least 15 miles around London. That's about 2 gallons on the consumption I've been getting... It doesn't seem to have had any adverse effects on my car.
 

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Digi said:
Gasoline is heavier than water. When the tank gets this low, there is a good chance that more water will go through the fuel line in the last gallons. Also, keeping a tank low adds to condensation and corrosion of the exposed surfaces and further contamination of the fuel. Keeping the tank full helps the engine get a better overall quality of gasoline and keeps the tank itself in better shape (unless we have a non-corrosive tank?)
Not sure I follow the logic there. If gasoline is heavier that water, the gasoline would go through first.... that is unless there is some sort of gravity defying phenomenon going on in the tank. Or the fuel outlet from the tank is above the bottom which isn't logical or practical in being able to use all the fuel in the tank if necessary.
 

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Filthy Monkey said:
Bearing in mind that I have to refuel my car every 2-3 days (so far my worst range on one tank is 92 miles. Ouch!!) I tend to run it pretty dry. So far I've discovered that with --- showing as the range I can get at least 15 miles around London. That's about 2 gallons on the consumption I've been getting... It doesn't seem to have had any adverse effects on my car.
If you get 92 miles out of a tank, that is 6MPG. I assume there may have been some fuel left on that oaccassion. But even basing it on the 15 miles for 2 gallons, that is really bad consumption. Do you use launch control at all the traffic lights? Or is the traffic that bad? If it is the later, I can't see any pleasure in driving the car under such conditions.
 

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beamaphile said:
Not sure I follow the logic there. If gasoline is heavier that water, the gasoline would go through first.... that is unless there is some sort of gravity defying phenomenon going on in the tank. Or the fuel outlet from the tank is above the bottom which isn't logical or practical in being able to use all the fuel in the tank if necessary.
It means you'll be sucking some water when the tank is nearly empty and the gas is sloshing around, making for a high percentage of impurities. It sat high on the gas on the full tank. Now you have no protection.
 

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beamaphile said:
Not sure I follow the logic there. If gasoline is heavier that water, the gasoline would go through first.... that is unless there is some sort of gravity defying phenomenon going on in the tank. Or the fuel outlet from the tank is above the bottom which isn't logical or practical in being able to use all the fuel in the tank if necessary.
I think he meant gasoline is lighter than water.
 

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beamaphile said:
Or the fuel outlet from the tank is above the bottom which isn't logical or practical in being able to use all the fuel in the tank if necessary.
Most tanks have floating pickups (attached to the arm that measures fuel level), meaning they don't just suck fuel out of the bottom of the tank. Since most impurities sink to the bottom, the lower you run it, the more likely you will pickup some impurities if there are some in the tank.
 

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By the way, I'm surmising that the same issues can apply to the tanks storing gasoline at the service station. It is possible for gasoline pumped into your car from the bottom of the tank to be God-awful. I once filled the near empty tank of my Porsche 928 at a rural service station in North Carolina. My car ran for a few beats and then crashed right there in the service station and couldn't be restarted. The 928 went to my Atlanta dealership by flatbed wrecker.

For it's resuscitation the 928 required that the fuel injectors be replaced, the fuel delivery system be repaired, and the gas tank be drained. I was shown a sample of the gasoline that was drained from my tank. It was BLACK and entirely opaque.

That event has somewhat shaken my confidence that pumped gasoline is always what it should be. Every time I see an "out of gas" sign on a service station pump, I'm prompted to wonder what was being pumped just before the sign was posted and the pump closed. Remember those little glass bubbles on the side of the pump that allowed you to see the gas being pumped? I wish the pumps still had them.

Richard
 

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After landing a date with my dream girl (a supermodel) in 1990 and taking her for a drive in my '83 911 SC Coupe with bad fuel gauge and running out of gas in some real nasty neighborhood (short cut),I would never be caught dead in any car with less then 1/3 of the tank.
 

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beamaphile said:
If you get 92 miles out of a tank, that is 6MPG. I assume there may have been some fuel left on that oaccassion. But even basing it on the 15 miles for 2 gallons, that is really bad consumption. Do you use launch control at all the traffic lights? Or is the traffic that bad? If it is the later, I can't see any pleasure in driving the car under such conditions.
London traffic - It really is that bad! On the occassion that I do actually get out onot the open road I generally kick the arse out of it through frustration so the fuel consumption doesn't really improve!!
 

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absent said:
After landing a date with my dream girl (a supermodel) in 1990 and taking her for a drive in my '83 911 SC Coupe with bad fuel gauge and running out of gas in some real nasty neighborhood (short cut),I would never be caught dead in any car with less then 1/3 of the tank.
You'd be surprised how many people think that it costs less money to drive around on a near-empty tank, my two college-age daughters among them.

Richard
 
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