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Survey - How low do you run your gas tank ?

3K views 25 replies 20 participants last post by  Jüri. 
#1 ·
Hi all

if my manual owner is correct my 02 ML500 has an 22 gal. gas tank. ML350 should be identical. I always go to the pump after the gas gauge is at lower end of E sign. At that point my mileage is usually 260-280 miles.

Curiously when I fill-up I usually can only put 17.5 to 18.2 gallons of gas. Now I don't expect to be able to resplenish it up to 22 gal. but still what account for such a big difference between 17 and 22 gal ? Any ideas ?

Also has anyone ran out of gas and later filled it up and noticed a big difference ?

I think for my part that Mercedes likes to keep its customers out of potentially dangerous situation by giving them a VERY large reserve.

Opinions welcomed.

Ps By the way I never use useless on board trip computer to give me remaining distance before running empty. Found it unreliable at best
 
#2 ·
They must have a large reserve because all the crap parts they put in for the gas gague. If you read around people have had tons of problems with filling up and the gas gague not going up. But I do not think it is with the 02 and up.
 
#7 ·
i always fill it up before it hit the 1/4 mark.
 
#11 ·
I notice light comes on just under the 1/4 mark on the fuel gauge of my 03 ML350. According to the trip computer I have 88 miles to go until empty. When I fill up with 88 miles to go I get about 17 Gallons of gas in the tank. If I ran it till empty I would get about 360 miles to a tank of Gas.
 
#12 ·
With raising cost of gas, I will top off my tank at least once a week and I look for stations who have the lowest prices. I rarely hit the 1/4 mark anymore.

I used to have the same issue where topping off the tank and fuel gauge will not show full. I had this fixed under my Starmark, it was the fuel sending unit.
 
#13 ·
I always let mine go all the way past the yellow light.. Because of the fuel gauge issue I have learned that I have more gasoline than it shows on my trip computer so I can drive it for a longer period of time.. All I have to do is park the car , let it sit for a little while and bingo.. I get an extra 2 gallons put in magically.. lol
 
#14 ·
uptown - 2/14/2006 12:26 PM

I always let mine go all the way past the yellow light.. Because of the fuel gauge issue I have learned that I have more gasoline than it shows on my trip computer so I can drive it for a longer period of time.. All I have to do is park the car , let it sit for a little while and bingo.. I get an extra 2 gallons put in magically.. lol
Magic fuel elves. Hook me up. [:D]
 
#15 ·
I run mine until it’s flat empty and the engine dies, then I call MBUSA Roadside Assistance. They give me two gallons of gas (for free!), which usually gets me to work and back, maybe out to lunch, and then I have to call them again![8D]

Seriously, I generally fill up when convenient, but I am usually around ¼ tank or less. I have driven until the TC told me I had 20 miles to go, which means I’d have had about 1.5 gallons in the tank and I was able to put 18 in, so that’s about right.
 
#16 ·
rudeney - 2/14/2006 3:10 PM

I run mine until it’s flat empty and the engine dies, then I call MBUSA Roadside Assistance. They give me two gallons of gas (for free!), which usually gets me to work and back, maybe out to lunch, and then I have to call them again![8D]

Seriously, I generally fill up when convenient, but I am usually around ¼ tank or less. I have driven until the TC told me I had 20 miles to go, which means I’d have had about 1.5 gallons in the tank and I was able to put 18 in, so that’s about right.

Never trust the trip computer i have driven for at least 20 miles when it said i had 0 miles left and the gas gauge was pinned on the line. I hate to go to the gas station and fill up with gas takes to long and people look at me funny so i only fill up when i hit 0 or if i am going on a long trip
 
#17 ·
Is anyone thought on running close to empty tank can give the fuel pump more stress and the tank can be filled with more air air?[8)]just the thought[:)]
 
#18 ·
JimB - 2/14/2006 5:55 PM

Is anyone thought on running close to empty tank can give the fuel pump more stress and the tank can be filled with more air air?[8)]just the thought[:)]
I would be more worried about the dirt and grime that supposedly builds up in the bottom of the gas tank over the years, i always get told dont let you car get that low or you will get junk sucked into your pump and lines.
 
#19 ·
Run it dry - push the button for MB service

I always let the light tell me when to fill it (then I ignore it for a while).

Doesn't the fuel in the tank cool the pump or something. Seems I remember reading we were not suppose to do what I have been doing for years (running it till almost dry).
 
#20 ·
I usually fill mine up when the needle is pretty close to E. I rarely get 300miles out of that, usually 280 or so.
 
#21 ·
I usually go 1 week between fill-ups and I am between 1/2 and 1/4. I never had a fuel gauge problems on the '03 ML350 and ran it down to empty only a couple times. Max fill was about 19.8 gallons.

Gas Mileage is better on the new ML and the gauge works too. [:D]

The pump sits in a well and there is a filter on the inlet so the pump is always submerged.
 
#22 ·
rudeney - 2/14/2006 3:10 PM

I run mine until it’s flat empty and the engine dies, then I call MBUSA Roadside Assistance. They give me two gallons of gas (for free!), which usually gets me to work and back, maybe out to lunch, and then I have to call them again![8D]

hahahaha thats a good one there rudeney...i was thinking...damn thats a great idea..always get 2 free gallons with every fill up lol!

i fill up when convenient..but never below the 1/4 from the bottom...unless you are on the 5 freeway...in between cow farms -.- lord knows there be a lot of cow crap out there...
 
#23 ·
Hey all.

I have an `02 ML320 and have the same issues. I average around 375 - 400km per tank. I also find the upper gas meter (### until empty) completely useless. It actually went up to 1800km until empty once on the highway driving at about 65mph for an hour or so!!

Anyway, I find that during the summer when the temperature goes up, that my gas needle will be at 1/2 tank 1 minute, and at 3/4 the next =) Crazy unpredictable.

I have found a way around the fillup problem though. I find that by holding back the circular plastic flap attached to the handle of the fuel pump nozzel while filling up, that it will continue filling until completely full. I was told by a service guy that the reason the ML prematurely triggers the pump to shut off before the tank is full is cause of the gas tank design. Apparently too many vapours collect while filling and trigger the pump sensor. SO, by holding back that circular flap, you allow some of those vpours to escape and stop the sensor from triggering early!

Crap thats a mouth full and a half!! [:D]
 
#24 ·
Whoever fills up at 1/4 mark is using less, than 70% of the tank capacity. That means waste of time and gasoline for pulling to the pump. I never have seen accurate fuel gouge in my life and I always drive by odometer. On cars with daily meter I reset it after each fill and at one point of ownership I take a can and drive it on reserve. My old VW diesel would make 120 miles, with fuel gauge showing absolute ZERO. I know, that our (wife) ML will make 300 miles on the tank, unless I drive on the desert with cruise control set at the limiter speed.
The problem with pump nozzle kicking prematurely is the vent tube, that connects to the fill pipe about 3" below the cap. Most of the tanks at the end of filling process produce some foam, that backing up thru that pipe shuts the pump off. In big RV tanks the diesel foam will shut off the pump with 20 gallons "air bubble". I always restart the pump 3 times, what gives me additional 2 gallons to the tank.
BTW I noticed, that when I speed up hardly on the 3-rd gear, I can get few miles above the limiter speed, before the computer "wakes up" and cuts it down. Anybody else with that experience?
 
#25 ·
RE: Run it dry - push the button for MB service

Andrew2004az - 2/14/2006 4:58 PM
I would be more worried about the dirt and grime that supposedly builds up in the bottom of the gas tank over the years, i always get told dont let you car get that low or you will get junk sucked into your pump and lines.
JimB - 2/14/2006 5:55 PM
Is anyone thought on running close to empty tank can give the fuel pump more stress and the tank can be filled with more air air?[8)]just the thought[:)]

gwwaterman - 2/14/2006 5:26 PM
Doesn't the fuel in the tank cool the pump or something. Seems I remember reading we were not suppose to do what I have been doing for years (running it till almost dry).
As Andy pointed out, the pump is in a well on the bottom of the tank, so it’s bottom. If there is any sludge or junk on the bottom, it’s going to get that regardless of whether the tank is full or nearly empty. Luckily, there is a particulate filter on the pump so that shouldn’t be a problem.

As for using the fuel as a lubricant or cooling device, it does do that, but again, the pump is always surrounded by fuel until the very last few ounces, so the engine will die and the pump will shut down before overheating.

Fuel is used to cool and lubricate the injectors and there is a slim possibility that running an engine completely dry could cause damage, but it’s very rare. When I worked at the dealership, we had at least one car on the lot run completely out of fuel once a week. The worst one was an S500 that I ended up driving around in for two days before it quite stuttering and hesitating, but after that, it was fine.
 
#26 ·
RE: How low gas? As far as possible, as Kajtek1 says.

I have once gone 467 miles on 23.05 gallons and three times have filled over 25 gallons on a tank. I always plan on driving as far as possible on a tank as I get less mileage sitting at a station. I normally go over 400 miles on a tank and average 17.56 miles per gallon since day one at 75K to date.

Enjoy, - - - <b><font color=#831525>Jüri</font></b>.
 
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