Fuel Gauge question
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Joined: May 2004
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From: Cerritos, CA
2004 E320
Fuel Gauge question
Does the half circle on the fuel gauge in the instrument turn black when your tank is completely full. On my guage all the bars turn black except for the very top one and it annoys the hell out of me 
My SA said that is normal. How about your guages? I've attached a picture.
My SA said that is normal. How about your guages? I've attached a picture.
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From: FL410
'05 E320 CDI, '08 BMW X5 4.8i, '11 Duramax 2500HD
Just rimmed my tank on the CDI and it too isn't black... guess it's a bug in the software. I'm **** and generally go crazy with stuff like that, but I have to tip my hat to you, you're really picky!
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From: North Scottsdale, AZ
'71 Pinto
Originally Posted by Yonask
Does the half circle on the fuel gauge in the instrument turn black when your tank is completely full. On my guage all the bars turn black except for the very top one and it annoys the hell out of me
Anyway here’s how I see it, the upper half circle is white because it is not the black bars that indicate filling but rather the white bars. As the tank empties black dominates the gauge and therefore the lower half circle is black; white – full, black – empty.
Last edited by konigstiger; Jul 14, 2005 at 09:12 PM.
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From: Valley of the Sun, Arizona
2011 E550, 2013 GLK
I just use the gauge as a rough approximation. Use the trip computer and call up the range remaining. It'll give you a better indication of how far you can go before you need to start looking for fuel.
Last edited by BudC; Jul 15, 2005 at 01:10 AM.
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From: Canada
2004 E500 / 2001 C240
It makes sense. Empty and full are not the same thing..
Black is empty, full is white. Look at it as the white is the fuel.
So it drops down and that black part of the tank is now empty.
Black is empty, full is white. Look at it as the white is the fuel.
So it drops down and that black part of the tank is now empty.
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From: Sacramento
'08 AM Vantage V8 - '03 E500
Originally Posted by atssystems.com
It makes sense. Empty and full are not the same thing..
Black is empty, full is white. Look at it as the white is the fuel.
So it drops down and that black part of the tank is now empty.
Black is empty, full is white. Look at it as the white is the fuel.
So it drops down and that black part of the tank is now empty.
Yonask: Some air remains in the tank even when when it's topped up in the filler neck, and M-B engineers left the half-circle in the fuel gauge unfilled to represent the air remaining in the tank. Actually, I made that up and I have no idea whether it's true, but feel free to use it, no charge, if it makes you feel better about the gauge.
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From: Canada
2004 E500 / 2001 C240
Originally Posted by DWP
M-B engineers left the half-circle in the fuel gauge unfilled to represent the air remaining in the tank. Actually, I made that up and I have no idea whether it's true,
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From: Cerritos, CA
2004 E320
Originally Posted by DWP
Some air remains in the tank even when when it's topped up in the filler neck, and M-B engineers left the half-circle in the fuel gauge unfilled to represent the air remaining in the tank. Actually, I made that up and I have no idea whether it's true, but feel free to use it, no charge, if it makes you feel better about the gauge.
I guess that works for me...
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From: Central California Coast
2004 SL55, 2005 E500 Wagon
Human factors engineering
I filled up my tank today, noticed the gauge, and thought about this thread.
I think the reason the engineers left the little half-circle at the top is to let you know whether the tank is full or empty, even if you don't know whether white is fuel or black is fuel. If you didn't know (and I think the way the engineers did it is backwards from what I would expect: I would expect white to be fuel; black seems to be the absence of anything), and the display were all white, the tank could be full on it could be empty. Same thing with all black. All you have to know is that more fuel raises the demarkation between white and black, and less fuel lowers it.
There's a test to see whether my reasoning is right. If it is, and the engineeers have thought this thing through, when the tank is dead empty, the little half-circle at the bottom of the tank should remain black. I've never run my tank all the way down, so I don't know whethter htis is true or not. Does anybody?
Jim
I think the reason the engineers left the little half-circle at the top is to let you know whether the tank is full or empty, even if you don't know whether white is fuel or black is fuel. If you didn't know (and I think the way the engineers did it is backwards from what I would expect: I would expect white to be fuel; black seems to be the absence of anything), and the display were all white, the tank could be full on it could be empty. Same thing with all black. All you have to know is that more fuel raises the demarkation between white and black, and less fuel lowers it.
There's a test to see whether my reasoning is right. If it is, and the engineeers have thought this thing through, when the tank is dead empty, the little half-circle at the bottom of the tank should remain black. I've never run my tank all the way down, so I don't know whethter htis is true or not. Does anybody?
Jim
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From: Los Angeles / Orange County
2005 E500 / 1993 MR2 Turbo
Bottom line is, if one doesn't know whether or not the fuel tank is full or empty they shouldn't be driving a mercedes. you shouldn't let the fact that the top semi-circle doesn't illuminate...come on now, you're driving a mercedes benz.
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From: Central California Coast
2004 SL55, 2005 E500 Wagon
Originally Posted by jameson75
Bottom line is, if one doesn't know whether or not the fuel tank is full or empty they shouldn't be driving a mercedes.
Jim
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From: Los Angeles / Orange County
2005 E500 / 1993 MR2 Turbo
Originally Posted by CASL55
Imagine that you've just picked up a rental car at Frankfurt airport, and it's an E class. Imagine that you've never driven a current-issue E. As you drive out of the parking lot, wouldn't you like to know if the Hertz folks really filled the tank?
Jim
Jim
respectfully I fully understand the dilemma you pose. However, we talkin in the masses here, but when you rent a vehicle, they usually make it a point to tell you and mark on the rental sheet how much fuel is left, so that one will know how much fuel to return the car with. It also comes down to common sense, when I first purchased my E500, I took a look at the gauge and new that the tank was full, by the black indicators. Reason being is if you take a closer look, the black indicators have a thin white line in between them, suggesting that the background is white and the black bars are the marks that move down as your fuel is consumed.
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From: Central California Coast
2004 SL55, 2005 E500 Wagon
Originally Posted by jameson75
respectfully I fully understand the dilemma you pose.
I don't know about you, but normally when I rent car at an airport, there's nobody from Hertz to look at the fuel gauge. I just walk down the row of cars until I find my name in lights, throw my bag in the open trunk, and get in. The key is in the ignition, and the contract is on the seat. I drive away, showing my driver's license and the contract to the gate attendant on the way out. Except for him, at no time have I talked to a Hertz employee.
Jim
