Why my MPG is low?

mattozgur · 06-15-2023, 02:35 PM

Hello folks!
My cars gas consumption is too high. Why is that?
2015 428i F32 using 93 octane Shell/Chevron
My best is 18.1 mpg while driving very slow on eco mode which is still low.
Just replaced O2 sensor and nothing changed. Spark plugs were changed 15k miles ago. Please help me solve this.
I have used Liqui Moly jectron injection cleaner, nothing changed.

Billfitz · 06-15-2023, 05:02 PM

Quote:

Originally Posted by mattozgur

My best is 18.1 mpg while driving very slow

You get the best mileage on the highway between 60-70 MPH, the worst in town.

F36_Paul · 06-20-2023, 08:27 PM

Our 4 cylinders just suck on gas during city driving. My city mpg is about the same as yours. Highway its 25-30mpgs.

chowser51 · 06-21-2023, 05:54 AM

'19 x2 m35i engine. mixed driving only gets me 26ish mpg. never use eco mode. best i got recently was on a 450 mile trip on Monday. It was 31mpg. Lots of A/C and some traffic jams. And lots of speeding. lol
Refilled when we got here and doing a lot of stop and go in city traffic. will see if it gets as low as yours. I always fill with 93 octane.

fe7565 · 06-23-2023, 04:15 PM

What engine is this? I have a 328i N26 and get about 26mpg in the city and 39mpg on hwy (based on the car's own mpg measurements).

I've never used eco mode after a first few months...did not see much of meaningful difference, but seems to limit acceleration).

Billfitz · 06-23-2023, 04:21 PM

11.7 MPH isn't average city driving, it's crawling. My bicycle is faster.

beefyman · 06-24-2023, 12:07 PM

Quote:

Originally Posted by Billfitz

11.7 MPH isn't average city driving, it's crawling. My bicycle is faster.

Yep, 78hrs to travel 886 miles at 11.3 mpg. Crazy!

Perhaps you should reset and see what the next tank gives you?

chowser51 · 06-24-2023, 04:58 PM

Quote:

Originally Posted by fe7565

I've never used eco mode after a first few months...did not see much of meaningful difference, but seems to limit acceleration).

I used it in my 430 to see it was about and that limited acceleration sucked. Especially if you need to get out of a dangerous situation. Hit the gas and it lags. That’s why I never use it.

S3RIES28 · 06-26-2023, 11:45 AM

Were your injectors changed/coded? this happened to me when i replaced injectors before i coded them to ECU.

06-15-2023, 02:35 PM	#1
mattozgur Registered 0 Rep 4 Posts Drives: BMW 428i F32 Join Date: Mar 2023 Location: Miami iTrader: (0)	Why my MPG is low? Hello folks! My cars gas consumption is too high. Why is that? 2015 428i F32 using 93 octane Shell/Chevron My best is 18.1 mpg while driving very slow on eco mode which is still low. Just replaced O2 sensor and nothing changed. Spark plugs were changed 15k miles ago. Please help me solve this. I have used Liqui Moly jectron injection cleaner, nothing changed. Attached Images Last edited by mattozgur; 06-15-2023 at 02:41 PM.. Reason: adding pics
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06-20-2023, 08:27 PM	#3
F36_Paul New Member 0 Rep 24 Posts Drives: 2018 BMW 430ix Join Date: Mar 2022 Location: jersey iTrader: (0)	Our 4 cylinders just suck on gas during city driving. My city mpg is about the same as yours. Highway its 25-30mpgs.
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06-21-2023, 05:54 AM	#4
chowser51 Colonel 2034 Rep 2,814 Posts Drives: F33 430 and F39 M35i Join Date: Feb 2009 Location: Cleveland, OH iTrader: (3) Garage List 2018 BMW 430i xDrive [0.00]	'19 x2 m35i engine. mixed driving only gets me 26ish mpg. never use eco mode. best i got recently was on a 450 mile trip on Monday. It was 31mpg. Lots of A/C and some traffic jams. And lots of speeding. lol Refilled when we got here and doing a lot of stop and go in city traffic. will see if it gets as low as yours. I always fill with 93 octane.
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06-23-2023, 04:15 PM	#5
fe7565 Lieutenant Colonel 553 Rep 1,590 Posts Drives: 2012 BMW 328i N26 Join Date: Nov 2013 Location: United States iTrader: (0)	What engine is this? I have a 328i N26 and get about 26mpg in the city and 39mpg on hwy (based on the car's own mpg measurements). I've never used eco mode after a first few months...did not see much of meaningful difference, but seems to limit acceleration). __________________ Help each other: if you manage to fix your issue (especially with help from this forum), don't be a dck and disappear. Follow-up by posting the solution so you can help others. Last edited by fe7565; 06-23-2023 at 04:28 PM..*
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06-23-2023, 04:21 PM	#6
Billfitz Lieutenant General 8270 Rep 16,120 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	11.7 MPH isn't average city driving, it's crawling. My bicycle is faster.
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06-26-2023, 11:45 AM	#9
S3RIES28 Enlisted Member 21 Rep 31 Posts Drives: F30 328i M Sport Join Date: Sep 2016 Location: Lime Rock, CT iTrader: (0)	Were your injectors changed/coded? this happened to me when i replaced injectors before i coded them to ECU.
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