Strange Gas Mileage From Recent Fill-Up - Really Odd
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
Strange Gas Mileage From Recent Fill-Up - Really Odd
I haven't had the chance to fully diagnose the issue "yet". But as I usually do when pumping gas, I fill it up to the top. I'm not the type to pump just a little bit here and there. Either all or nothing.
Allow me to preface with...
- Entire fuel system & gas tank has been replaced last year (the recall)
- I haven't floored it or driven crazy during this past fill-up
- I haven't left the car on or running
- I always reset the gauge after pumping gas
So... a few days ago, I was almost out of fuel. Probably a bad habit, but I usually pump gas when the light goes on. I filled it up all the way. I avoid "over-filling".
I get in the car, turn it on, and reset the gauge (miles driven from the last fill-up). It's typically between 315-355 miles on a full tank.
A couple days later, as I'm sitting at a red light. I glanced down at my gauges and noticed that I'm at half (which is fine). I drive a relatively good amount of miles day-to-day.
The only issue was... at half tank remaining... it showed only 69 miles driven!
That's when I wasn't sure what to think. I'm now at a 1/8th of fuel remaining and only 119 miles driven.
Kinda' odd. Has anyone experienced this?
Now I'm worried what the next fill-up will be like.
Allow me to preface with...
- Entire fuel system & gas tank has been replaced last year (the recall)
- I haven't floored it or driven crazy during this past fill-up
- I haven't left the car on or running
- I always reset the gauge after pumping gas
So... a few days ago, I was almost out of fuel. Probably a bad habit, but I usually pump gas when the light goes on. I filled it up all the way. I avoid "over-filling".
I get in the car, turn it on, and reset the gauge (miles driven from the last fill-up). It's typically between 315-355 miles on a full tank.
A couple days later, as I'm sitting at a red light. I glanced down at my gauges and noticed that I'm at half (which is fine). I drive a relatively good amount of miles day-to-day.
The only issue was... at half tank remaining... it showed only 69 miles driven!
That's when I wasn't sure what to think. I'm now at a 1/8th of fuel remaining and only 119 miles driven.
Kinda' odd. Has anyone experienced this?
Now I'm worried what the next fill-up will be like.
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Joined: Dec 2015
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From: Dublin,OH. Ft Myers, FLA
E63 AMG 2007
Do you think the mileage recorded is correct? That is to say do you think you are getting much lower miles per gallon, or that the miles driven are not being accurately measured? Could be the gauge is not accurate?
Last edited by Dublinoh; May 11, 2017 at 04:42 PM.
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From: In the Shadow of the Tetons
2013 ML350 Bluetec
Not related to your question, but in my opinion it is a bad idea to run the tank less than 1/4 full. Why? Because the fuel pump is immersed in fuel to keep the pump cool. Running the tank empty deprives the pump of its cooling bath and results in an early demise of an otherwise long-lived system. And... How embarrassing would it be if you needed to quickly get out of town but your tank needed to be filled first because you were down to only a few gallons?
To your query: What Dublinoh said. Is your gauge (either fuel gauge or odometer) reading accurately or are you actually getting crappy mileage?
To your query: What Dublinoh said. Is your gauge (either fuel gauge or odometer) reading accurately or are you actually getting crappy mileage?
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From: In the Shadow of the Tetons
2013 ML350 Bluetec
I may not be able to walk away from an E55 in the short run (but with 350 torques I'll not be too far behind), but it sure is nice to get nearly 800 miles out of a tank of diesel fuel if I want to... 
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
Not related to your question, but in my opinion it is a bad idea to run the tank less than 1/4 full. Why? Because the fuel pump is immersed in fuel to keep the pump cool. Running the tank empty deprives the pump of its cooling bath and results in an early demise of an otherwise long-lived system. And... How embarrassing would it be if you needed to quickly get out of town but your tank needed to be filled first because you were down to only a few gallons?
I never knew that concept. Now that I know, I won't let it reach the "gas light" anymore. I appreciate the passing of your knowledge.
Regarding your last sentence... LoL. Unfortunately, it's happened a lot. Haha.
To your query: What Dublinoh said. Is your gauge (either fuel gauge or odometer) reading accurately or are you actually getting crappy mileage?
I never knew that concept. Now that I know, I won't let it reach the "gas light" anymore. I appreciate the passing of your knowledge.
Regarding your last sentence... LoL. Unfortunately, it's happened a lot. Haha.
To your query: What Dublinoh said. Is your gauge (either fuel gauge or odometer) reading accurately or are you actually getting crappy mileage?
When the car was stock, I usually filled up around the range of 315-330. After all my mods, I still get descent mileage. there were two rare instances when I actually reached 355 miles. Only cause I drove like a grandma the entire tank. I was curious to see the most miles I can pull off. LoL. Doesn't usually happen though.
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From: Cypress, TX
'06 E55, '15 Jeep SRT8, '94 Mustang GT
Are you sure that the pump actually filled your tank? We had an issue a few weeks ago with a local station. My Jeep normally takes ~$60 max for a fill-up. I was halfway watching the fill-up and noticed that it had reached $75, then stopped directly at $80 showing that it had pumped around 30 gallons, but my tank only holds 25. Without going into a long story, which can be given later on request, we got a refund for the extra 5 gallons, then started to leave and found that my gas gauge was only halfway full. After more arguing, they bagged the pump and refunded us another 12 gallons of fuel, claiming it was a calibration issue.
I'd watch the rest of your tank for additional signs of a problem before diagnosing something that may not exist.
I'd watch the rest of your tank for additional signs of a problem before diagnosing something that may not exist.
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Joined: Sep 2014
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From: Worldwide
2007 Mercedes E63 AMG
wow...the most I ever got was 320 miles 100% freeway driving. combined I usually pull 240-270 a tank. I usually fill up before empty though, but calculated mpg with 100% freeway driving was 20-21 mpg
maybe your sender unit is going out or dirty? my Audi A4 does the same if I don't always drive to empty and fully fill up often. usually it's because the sender unit is dirty.
if you do find out what is wrong please report back. good luck!
maybe your sender unit is going out or dirty? my Audi A4 does the same if I don't always drive to empty and fully fill up often. usually it's because the sender unit is dirty.
if you do find out what is wrong please report back. good luck!
Last edited by hachiroku; May 16, 2017 at 01:55 AM.
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2001 E320 Wagon, 2006 LBZ Silverado, 2007 E63 (sold), 2001 E55 (sold)
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From: Dublin,OH. Ft Myers, FLA
E63 AMG 2007
My last 300 mi highway trip mileage was 22.7, with a three gallon reserve that's 380+ miles. Also don't forget some of us have 21+ gallon tanks and some have 16+ tanks.
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From: Alexandria, VA
07 E63 AMG, 10 C63 AMG, 07 E63 Designo, 07 E350, 09 C300, 07 C230
also it's not a good idea to ever let your car get extremely low on fuel, as there is sediment at the bottom of your tank, and that sediment could possibly get sucks up in your fuel pump, filter and lines. 
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From: MA
2008 E350 4Matic, 2011 E350 4matic
I think a key question is what was the mpg reading. That will tell you how many gallons it thinks was consumed to get to the 69 miles. If it's under 7, then everything is probably fine. Otherwise it's either a gas leak, bad pump, bad gas gauge etc.
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
My mistake was I never bothered to look at what my MPG was. I was so caught up with the fact I only drove 69 miles to half a tank that I didn't bother to check the other readings.
