MPG not so good

Tara Lowry · Feb 6, 2017

I was wondering if anyone has had any issues with poor fuel economy. I have had my 2015 GLA 4matic for a few months. I work 114 miles from where I live and make the drive 9 times a month roughly. My fuel economy hasn't been that great. Mercedes says there is nothing wrong but it has gotten worse. My drive is mostly flat. Last time all Hwy I got 25 there and back 27 mpg. I drive it in economy at that is 99 and 88 percent.
Thanks
Tara

Wayne · Feb 6, 2017

Speed makes a big difference. On our 45, at 60 mph we get just over 30mpg (this was in Europe with 93 octane, figures drop by 2 with California 91 gas). At 110 mph we drop to 20. This seems to be fairly linear, dropping about 2 mpg per 10 mph increase. I found I could do better with hills where I could engage sail mode. This was true with Pam's Lexus RX400h as well. Getting good gas mileage is a different paradigm than it was 20 years ago.

turbolink · Feb 6, 2017

Welcome to the GLA forum Tara. Sorry to hear your mileage experience, would seem like you should have better performance. I see from your photos that you're driving in the Economy mode as you mentioned, but you didn't say if you are using the minimum octane fuel requirement, 91 or 92. How is your ECO start/stop system working? That can gain a mile or two per gallon depending on varying circumstances.

Also, in your 114 mile drive, do you have a lot of traffic or stoplights? Do you do other short distance travel besides the 114 mile trip? One of the console screens monitors your realtime mileage performance, up and down as you drive, as opposed to the average mileage screens you showed. That could give you valuable insight to what's sucking down fuel. I am averaging about 26 MPG in short distance island driving in the Comfort mode, so your experience might not be too far off expectations. I've only gotten over 30 MPG once when I drove one of our three freeways that goes 20 miles or so. Would love to see how I'd do on a US mainland long distance trip.

Most of all, are you doing full fill-ups to the same point (usually the first nozzle click) and resetting all your screens to the default settings, as well as doing manual math of trip odometer miles divided by gallons of fuel to compare numbers? It might be your computer readout is skewed by not getting reset upon fill up. I find the two rarely agree for me, with no real correlation either way.

BTW, if 82 MPH is your standard speed, that might be a clue as well.

caug · Feb 6, 2017

colder weather will hurt mpg.
lower pressure in the tires during cold.
traveling speed,
also most importance is that the gas quality changes for cold weather with special additives use by gas companies at least in MAss.
so tuning the cars also not a good idea due to the additives in the gas.
C

23481 · Jun 1, 2017

Unbelievable marvelous high MPG !!!

Tara Lowry said:
I was wondering if anyone has had any issues with poor fuel economy.

The GLA 250SUV (non 4Matic) delivers amazing high MPG for such a fast accelerating SUV with high ground clearance.

I just made an epic road trip from Orlando to NJ, and then northward on to Portland ME and Booth Bay Harbor. After 9 hours of driving (non continuous), 576 miles, at average speed of 63 mph my average MPG was 34.5 mile/gallons !!! This is phenomenal, the ride of this car at 75 mph is absolutely marvelous. I have front strut brace, first oil change at 4,750 miles and Nitrogen filled tires at F 33 psig and R 29 psig respectively. The ambient temperature throughout the trip was about 58ºF - 84ºF.

I used extensively Distance Pilot Distronic, I had it set at 75 mph when traveling on I95 all the time, with exception coming out of NYC at Saw Mill Parkway.

Foxbat121 · Jun 1, 2017

On my recent trip from Washington DC to Toronto, a round trip for about 1000 miles, my average MPG is around 29mpg. 2017 GLA 250 4matic and 2 passengers. Average highway speed is about 65 to 70mph. This has been the best I have seen on any AWD cars I have ever driven (I have owned many Subarus).

Speed is a main factor for fuel consumption. Most passenger cars are design to have best fuel mileage at 55 to 65 mph. Higher speed will cause higher fuel consumption.

rjpeaks · Jun 1, 2017

I am at about 12 MPG. worse than my S4 with the 4.2 V8. walk with a limp...

m-type · Jun 2, 2017

lol race start at every light on the pch?

Right_mr · Jun 2, 2017

i've only done 3700 miles (in my 2017 GLA 45) but will soon do a 700 odd mile round trip in a week's time when i take a road trip to the southwest of the UK. So far, the overall MPG has crept up to 25.6mpg. A lot of my driving is urban driving. Best i've been able to do on short journeys (approx 30 miles) including motorway driving is 35mpg. I had used BP 97 fuel up to this point but have now switched to Shell 99 which seems to make the car run smoother. I'll update you guys on how my long journey goes in terms of fuel economy

rjpeaks · Jun 2, 2017

jump in my man...

recent cars: S4 Avant, 335 M-sport, Porsche 981, now this.

In other news, son's car hit this afternoon. bummer

Born2fly · Jun 3, 2017

I noticed poor fuel eco when I first bought the car, then I discovered that not every car dealership that sells a car used will check the air filter in the engine. https://www.knfilters.com/air_filter/mercedes_benz_gla250.aspx Probably the best air filter for the engine to date. I'm still running a 18.00 air filter which can be acquired from Rock Auto as I've been told all MB filters are nothing but Mann Filters re-labeled( MB Price for new air filter $54.and then another $50 just to put it in. Save yourself the heartache and grab a T-20/25 torx bit unzip 4 screws plop in new air filter, re-screw back into place and presto. Next up is the spark plugs. I've noticed running newer spark plugs that the engine has gained some MPG's coincidence I'm not sure but logic tells me that it only makes sense( The newer Laser Irridium from NGK) are pre-set from factory, but a lot of stuff needs to be moved in order to get at the plugs ( Have a mechanic do it, it'll cost $150.00). If you allow the engine to breathe cleaner air, and the MAF sensor is getting sufficient air, engine can breathe more and generate more MPG's. Also as many have mentioned tire pressure. It really doesn't matter whether or not the car has Nitrogen or regular air.

Tuning the car could be an option however.......to me it sounds like there's something else clogging the system.

There's another thread dealing with spark plugs on here.

23481 · Jun 9, 2017

Born2fly said:
.... I've been told all MB filters are nothing but Mann Filters re-labeled.... I'm not sure but logic tells me that it only makes sense( The newer Laser Irridium from NGK) are pre-set from factory, but a lot of stuff needs to be moved in order to get at the plugs ( Have a mechanic do it, it'll cost $150.00). If you allow the engine to breathe cleaner air, and the MAF sensor is getting sufficient air, engine can breathe more and generate more MPG's.

Yes ... MB engine oil here in US is re-branded Mobil 1, and air/oil filters are re-branded Mann. My experience with spark plugs, specially with the extra long life the NGK Iridium sparks is that after 60K miles (on my 2009 BMW) is that it will "freeze" and impossible to unscrew them. First they are very deeply embedded and spark sockets are of very thin wall, I would yank them out at 50K miles or so, clean them and re-install with anti seize thread compounds. The MAP sensor will fowl up after 50K miles or so. All you need to do is (CAREFULLY) spray with MAP sensor cleaner spray. If you touch the sensor element you ruined it.

Nitrogen filled tires is a preference, there a lots of skeptics that do not see the benefit this. It is used in the military, commercial fleet and in aviation. It is proven to preserve the malleability of the inner rubber walls, slow down dry rot, increase longevity of TPMS and more volume stable to due to temperature fluctuations. I know at least that my MB dealer (Maitland FL) uses nitrogen, so does one other giant retailer - Costco (they use green colored valve caps).

The best mileage I got (34.2 mpg) was when I filled up my full tank with Sunoco brand Ultra 93. I have yet to find gas with 100 octane.

Boxster986S · Jun 5, 2017

Made a quick 150 mile round trip to Indianapolis last weekend, mostly on I65 cruising with traffic somewhere between 77 and 88 MPH. Got 34.0 MPG southbound with a tailwind, 31.5 MPG on return against the wind. My GLA 250 has 30K miles and was running 93 octane fuel.

Wayne · Jun 5, 2017

FWIW, I have found the higher octane European fuel returned better mileage than the 91 octane we have in California.

GLAowner · Jun 6, 2017

I think the real culprit is ethanol in US gas - with inherently a lower energy content. We all pay for that and lose.

rjpeaks · Jun 6, 2017

we have selected gas stations that carry 100.

https://www.6speedonline.com/forums/997/142051-socal-100-octane-pump-gas-list-locations.html

and yes it is very pricey. There's one in Newport.

GLAowner · Jun 6, 2017

Using a octane rating above the nominal 93 gets you nothing. It's not the lower 91 that yields lower MPG; it's the ethanol blend. 91 lowers performance (peak power/torque) but has little effect on MPG because the ECU adapts to the lower octane with the appropriate engine mapping.

Ideally these engines should get ethanol-free 93 octane gas - to get the advertised performance/MPG.

One can blend 100 octane with 91 to get the prescribed 93 (no benefit in going above that). Doing that one gets the nominal performance. But that does not improve MPG, because ethanol is still there and in addition 100 octane usually has ethanol.

Wayne · Jun 7, 2017

Energy density is a bear. We have ethanol because we have farm subsidies. Without a better catalyst, more energy goes into getting ethanol than we get out of it.

GLAOwner is spot on and I am kicking myself for having forgotten what he has pointed out!!!

BTW, ethanol can be really bad on seals and has caused some fires due to leaking gas in older classics. This is not a problem for modem cars, but I swear I have lost more than a couple chain saws and other yard tools on account of it. The gas pumps stop pumping. I now spend ridiculous sums of money to buy small cans of premixed gas from Home Depot and it has paid off with tools that no longer fail.

GLAowner · Jun 8, 2017

Wayne said:
...I have lost more than a couple chain saws and other yard tools on account of it. The gas pumps stop pumping. I now spend ridiculous sums of money to buy small cans of premixed gas from Home Depot and it has paid off with tools that no longer fail.

A shame, really! A product I have been using on older cars is StaBil 360 Ethanol Treatment. I wonder if that would work for small gas powered tools.

Even though modern cars are certified to use E10 I see no harm in using StaBil 360 on those too (1oz/5gallons of gas).

Fbsdmd · Jun 7, 2017

We have a local Sunoco station that has ethanol free 93 at one pump. I might try a few tanks. Don't what the price is, but it's undoubtedly more. Might be worth mixing 89 with ethanol and the ethanol free 93. Is it possible where you live that there are stations that sell ethanol free, and you don't know it?

Wayne · Jun 9, 2017

Use caution with anti seize on spark plugs. You shouldn't. See the attached photos from my 997 book. Or look it up on the web.

The atmosphere is almost 80% nitrogen. This is more inert than oxygen and does not absorb water that can amplify pressure change with temperature. I like nitrogen in my tires. But I use atmosphere when in my garage or at gas stations.

23481 · Nov 10, 2017

Wayne said:
Use caution with anti seize on spark plugs. You shouldn't. See the attached photos from my 997 book. Or look it up on the web.

I couldn't agree with you more that using anti seizing compound on any fastener will cause the thread to "creap" as shown on your photos. The lubrication provided by the anti-seize compound will "over torque" the thread thereby exceeding the torque limits. I set the sparks to a lower value; of course the danger is that it may cause gas blow by.

Right_mr · Jun 23, 2017

Right - so here are some stats for my journey back from cornwall:
Miles travelled: 270
MPG: 30.7
Average speed: 55mph
Driving modes: a mix of some comfort and a lot of sport
Petrol used: Shell V Power and some residual BP 97 octane
Time taken: approx 4 hours 40

It is worth pointing out that there was hardly any motorway involved apart from a few miles on the M3 motorway. The rest of the journey was exclusively A roads being the A31, A30, A303 mainly with speed limits ranging from 30, 40, 50, 60 and 70 miles per hour and moderate traffic in some parts. There were tons of roundabouts and slow vehicles that needed some swift overtaking.
The journey also involved some high speeds too to make up for the heavy traffic for some parts of the journey and the low speed limits for various portions of the journey so i would be averaging around 95mph for quite a few national speed limit sections of the journey which is how i managed to keep my average speed of 55mph decent enough.

Overall , the fuel economy is very respectable given how i was pushing the vehicle with lots of fast accelerating etc.

ahhl · Oct 19, 2017

i am getting about 9km/l ie about 25mpg.
short travelling urban area daily 30km total. takes about 2 hours. in comfort mode.
atm testing the eco mode, whether any different

TheThirdPhase · Nov 11, 2017

OP doesn't have a 45 though...

Without location info, it's impossible to be sure, but especially as the GLA is FWD based, I don't see the point in the 4MATIC version. FWD is just fine in the snow (What gets people is usually the "stopping" part, on which all vehicles are on equal ground), and the AWD linkage and weight eat fuel economy. The 250 doesn't have enough power to suffer from torque steer (and Honda just proved that bar is climbing ever higher), so to me, there is no reason to buy the 250-4 over the 250. If you suffer from severe winters you should have snowies anyways, and in a pinch one can always back their FWD vehicle up the hill.

I think the 4MATIC version is a "buyer peace of mind" money-add with limited at best actual benefit. Even on the 45 you're very aware when it brings the back end in. I'd really like an STI-style selectable center diff, but MB is new to the AWD game, and that diff and the driveline are very specialized hardware.

Fbsdmd · Nov 11, 2017

I've had mine for two winters, and though there hasn't been a lot of snow, there has been enough to get a feel for how the GLA deals with it, and it did very well. It was 17 deg F this morning; snow can't be far off, it will be fun to try again with the new tires. I have had several FWD cars over the past years, and have found all of them to be quite good in the snow. Definitely agree-we're all in the same boat when it's time to stop.

ahhl · Nov 12, 2017

tested over weekend 500+km highway
i am getting 32mpg, not impressive considering i am driving in Eco mode

compare to my old Fiat Grande (12yrs old) , I am getting 42mpg on highway driving recently

Sent from my HUAWEI MT7-TL10 using Tapatalk

Art Krummel · Jan 10, 2018

I haven't rated mpg yet - waiting for a long trip. if I get 32 mpg I will be happy - my 2012 Honda CRV got about 30 mpg.

Eugene_C · Jun 24, 2018

On the Highway I'm getting 32-34 mpg exit to exit with premium fuel. I set it the adaptive cruise at about 73-76 mph and just leave it there. In straight 100% city driving I get 19-22. In mixed or intermediate driving I get 25-28 mpg. Car is 2016 AWD.

schorert · Jul 20, 2018

I get around 20-22mpg around town with spirited driving sprinkled in....I'm amazed that if I'm on it pretty hard that the GLA45 gets around 14mpg... still better than my 8cyl AMG that averaged around 12...and could be driven down to about 9mpg.

Wesleypalms · Jul 31, 2018

1500 miles into our trip this summer getting 32.2 mpg with a 4matic. Driving about 3 miles over the speed limit. San Diego to Spokane through the Eastern Sierras, Tahoe, Reno, Boise then up the 95 to Coer Dalene and Spokane. Very pleased with the mpg, ride, and passing power. We'll be in Seattle soon to see our new grand daughter

gbarringer · Jul 31, 2018

Wesleypalms said:
1500 miles into our trip this summer getting 32.2 mpg with a 4matic. Driving about 3 miles over the speed limit.

What is the general speed limit. Driving 3 miles over 55 and 3 miles over 65 or 70 can make a big difference. Is the 32.2 using the display on the car or by miles divided by gallons used. I find the display is reporting a higher number than when you divide miles by gallons used.

Wesleypalms · Jul 31, 2018

Good question about mpg vs mph. The average speed limit was probably 65. There were a few places as fast as 80 in Idaho. Some mountain passes were 55. I think I will check the gallons used and see compare it to the cars computer.

MPG not so good

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