17rdx

I recently got a 2017 RDX in January and have 1100 miles on the odometer. My MPG is about 13.9 (for mostly city driving). I think this is very low compared to the 20 MPG advertised on Acura's website. I'm pretty light on pressing the gas and brake. Also, I don't even turn the A/C on. I heard that resetting the ECU would raise the MPG. Is that true? Any recommendations? Thank you

RDX-Rick

You didn't complete your profile, so we don't know where you are located. If you are in an area with cold winters like I am in Ontario, then it is normal for fuel economy to drop during this time of year. My 2016 RDX has been through 2 winters now and my lowest reading was 15.1 MPG. If you allow your RDX to idle for long periods to warm up, then you will see less than that.

Are you determining your fuel economy from the RDX's information display, or are you calculating it by doing the math? I think you will have to wait for warmer weather before you know if you really have a problem. You may also need to check fuel economy on a long highway drive to see the best fuel economy possible. In my case the best tank I ever had was 28.8 MPG. So my range has been from 15.1 to 28.8 taking in to account both temperature extremes and city/highway driving.

RDX10

The other thing to note is that you still have to get past the break in period, wait till the summer and around 3000miles to see what it's like. It should improve steadily.

17rdx

Yes, I have done the math and it comes out to be about 13.8 mpg. My dealer told me that the break in period is 10,000 miles which I thought that it was ridiculous.

17rdx

I had a BMW X5 before and the MPG was way better than this car. I love this car but it's just the MPG that ruins it.

thoiboi

Winter blend fuel

RDX10

Ok but 13.8 mpg is ridiculous still even with winter blend.


OP, 10000mile break in is absurd, if it stays low in the next couple months and few hundred miles take it in and insist they look at it. 13.8 mpg is ridiculous.

17rdx

Thank you for replying! My dealer refused to reset the ECU and said that there's nothing for them to do (as of now).

R. White

My average is 22.8 with about 90% non highway driving. '17 AWD. I run regular grade Mobile and Shell fuel.

Doobiewah

I agree that 13.8 is quite low. We get around 20ish for mostly city driving, with 28 on the hwy at 80mph.

On some cars, you used to be able to disconnect the negative on the battery for an hour or so and re-connect to get the ECU to reset...not sure if this would work on the RDX, though. (of course you'd lose your settings.....)

OP: You didn't mention it; however, I presume you are running premium, correct?

17rdx

Yes, I'm using premium gas.

GrimXDR

I have 3500 km on 2017 RDX, 80% city driving in busy peak traffic, dash shows average of 14.0L / 100km (~16.8mpg). occasionally i see high numbers like 17-19L / 100km (12-13mpg) in slow and uphill traffic, but it averages out overtime.

17rdx

Do you guys think that there's something wrong with my car?

RDX-Rick

If it feels like you can accelerate with full power I doubt if you have an engine problem.

The cause could be

• You need a little more time to break in the engine.
• Economy will increase as the weather becomes warmer
• You let your vehicle warm up by letting it idle.
• Your tires are under inflated
• You have a seized brake caliper causing brake drag. Does your RDX roll to a stop quicker than expected?
• You are driving in sport mode the majority of the time, or in manual mode and you are keeping the engine running at higher than needed RPM's
• There is a problem with the fuel you are using. Try a different "Top Tier" brand.
• Try checking your fuel economy on a long highway trip to rule out your driving habits and traffic conditions are not the cause

17rdx

I use 76 gas and I have not experienced the brake problem. Thank you!

musty hustla

13mpg doesn't seem normal to me. Our 13 RDX does about 65% city driving* and LOTS of stop and go. We haven't gone below 20mpg ever.

*BTW we calculate our city/highway percentage based on average speed.

CanTex

We just passed 1700 miles and consistently get 26 - 27 on the highway, depending on my right foot and the speed limits, then 19 - 22 general around-town, not much stop and go. Like our last RDX, the indicated MPG is optimistic. That's miles driven divided by gallons used using a calculator, not what's shown on the dash. Our TLX's instrument panel indicator is pleasantly conservative with higher actual mileage than shown.

What concerns me now is range. I need to look it up but they must have shrunk the gas tank between the 2013 and 2017 models.

CanTex

We just passed 1700 miles and consistently get 26 - 27 on the highway, depending on my right foot and the speed limits, then 19 - 22 generally around-town, not much stop and go. Like our last RDX, the indicated MPG is optimistic. That's miles driven divided by gallons used using a calculator, not what's shown on the dash. Our TLX's instrument panel indicator is pleasantly conservative with higher actual mileage than shown.

What concerns me now is range. I need to look it up but they must have shrunk the gas tank between the 2013 and 2017 models.

17rdx

Thanks! I contacted Acura

srpuywa

I drove my wife's 17 base model yesterday and was getting 25-31 mpg on the gauges

012TL-GLM

Winter fuel this season has been worse than i can remember mpg wise in all our vehicles. I have a silverado that normally gets 13, lucky to get 10, my charger (on nice days) is down to around 15 in town, and our '16 RDX AWD is averaging 16 in town. We just took a 500 mile road trip last weekend and my average went up to 28 according to the computer. A couple days of stop and go driving brought it right back to 16. I drive it like i stole it so im not going to complain, love the get up and go of the 3.5

17rdx

My mpg went up to 14.4 so I guess it would go further up.

Ludepower

I pick up my rdx this weekend. How do you guys calculate your gas mileage. I'm an idiot I know.

horseshoez

iTrader: (2)

Easiest way is to look at the computer; the car calculates it for you.

egads

I think the instant MPG is not accurate enough for anything beyond casual interest.

Here is the real way to calculate MPG:

Fill the tank only until the pump clicks off.
Reset one of the two trip mileage meters.
Next time you buy gas, fill again the same way.
Divide the miles shown on the trip meter by the gallons used to refill.
That is the actual MPG (or as close as you can get because fuel pumps may vary)

I personally always get a receipt and write down: the trip miles, the total miles, and the MPG result from doing the division.
The total miles can come in handy if you forget to reset the trip miles when refueling. There is a setting in the MID to have one of the
trip miles reset whenever you refuel. When doing it that way, you have to write down the trip miles before opening the fuel filler door.

My wife uses a little book, I keep the receipts in a clip. For tax purposes I usually put the year in large letters on the first & last one.

horseshoez

iTrader: (2)

Hmmm, I would argue the Average MPG is considerably more accurate than the old school miles divided by gallons approach. The best approach is to compare the running average from the Average MPG display and compare it to the running average of say, 10 tanks of fuel. Odds on bet they are within a few percent of each other. Once you determine a correction factor (which in the case of my car is -0.9%), then you can accurately determine your fuel economy for any given tank.

ronvanr

What did the car say your average MPH were?

fogdoctor

OK, here it is: I get literally 10% better fuel economy with 87 than with 91 octane. Therefore, I'm back on the Wawa/Sunoco/Exon 87 octane swill and I am back to 27-28mpg. If I switch to 91 I will go back to 23-24mpg with the same mostly highway driving at the same speeds (lots of cruise). Not sure why I does it but I can reproduce it at will so obviously I will be using 87 from this point on. I am not able to feel any difference in performance with the standard tune.

I'll may do the Ktuner stage 2, in which case I would have to go back to 91 but short of that there is no reason to run higher octane in the RDX IMO unless you just like to burn money. Is anyone (without more boost and/or advanced timing) seeing any performance advantages or MPG advantages with 91 over 87?

horseshoez

iTrader: (2)

Ten percent??? LOL, sorry, not buying.

fogdoctor

I would not either but that is what mine does on my mostly highway commute at 60-70mph. If I put in higher octane, fuel economy drops by 3mpg within about 1 tank. No, it does not make sense but I can reproduce it.

Could it be minor differences in the way I drive? I suppose, but I'm on cruise control a ton so I don't think that is it.

samiam_68

Is your car fully stock or do you have mods?

iHondaGuy

Really Fuel economy drops with high octane. Anyone else experience this? That's like a double whammy - pay more for the fuel and get less gas mileage.
I've been putting 93 octane from Shell on both the Acuras because that's what is "recommend". I'm tempted to try the lower octane (87) on a continual basis but just afraid of messing up the car since I plan on keeping it for longer. The other day the TLX got a fill up - I asked for 93 but the guy put in 87. I didn't realize it after I got the receipt. I ok with it once in a while and the car isn't driven like it would benefit from the high octane anyways.
I'm no expert with octane, engines and mpg, but if the engines can take 87 octane without risk that would be great.

horseshoez

iTrader: (2)

There is no explanation for it because it doesn't happen. It may happen in that person's mind, but in reality, sorry, NOT.

hans471

When people compare mileage between "high" and "low" octane fuel they often do it with a very small and irregular drive cycle. There is no way you can fill up the tank with one, then fill up with the other and compare. The sample size is just too small and the variables are just too great. I use to have a long commute to work (like nearly an hour each way) and for fun I decided to do some testing. To make the results more accurate I ran the vehicle for one month (30 days) on each type of fuel and compared the numbers. While this was not 100% controlled it was at least a much better sample size than one tank of each. What I found was that I did get a very small increase in fuel economy with the higher octane fuel. Now, this was interstate driving at higher speeds during rush hour through the country side so there were driving conditions where the higher octane fuel would have benefited the vehicle.(Higher speed and engine load). The test vehicle was a Mitsubishi Eclipse, five speed manual, with the twin cam, four valve higher performance engine. The vehicle ran fine on either the high or mid level octane fuel. The mileage difference was there, but it was small. When I did the final math the results were clear: A very slight increase in mileage but a larger increase in price of fuel. In simple terms: With the high octane fuel it was much more expensive to run the car. If there was a performance difference I couldn't feel it driving on a public street at normal legal speeds.
I have tried both 93 and 87 octane fuels in my RDX. I can tell no difference in either during the normal driving I do. I see no reason to pay a much higher price for the 93.
BTW, as most of you know, 93 octane fuel is "recommend" for the RDX, not "required". Also, if you research this subject you will learn that the higher octane fuel is rarely needed in normal driving . High temperatures, heavy load and lots of boost...yes it will help under those conditions. Normal driving...not required and a waste of money.
For fun and knowledge here is a good 46 minute program on Modern Marvels about the history of gasoline. It has a good bit of information on octane in it.

Jordster

So, it can DEFINITELY take 87 without consequence (as per the manual). It's the same engine is in the Accord, save for some of the plumbing. It's stated power is 252 hp in the Accord (where regular is "recommended") and 272 hp in the RDX (where premium is "recommended") but it's all marketing - the 272 hp puts it at the top of the class for 4-cyl luxury compact crossovers. If you're never pushing past 60% throttle or so, the higher octane fuel will make no difference. On the other hand, going to Shell is a good idea. Clean top-tier fuel is worth the money over no name gas almost every time (depends on the no-name gas, of course).

I don't own an RDX (yet) but I do own an Accord 2.0T. I ran premium for the first few thousand kms. Then I switched to regular and almost never went back. I track my mileage and noticed no change at all. I don't feel a lack of performance, though I rarely floor it.

egads

The second generation RDX (2013-2018) is a V-6. That engine, with a 87 octane recommendation is used in the Pilot, Odyssey, Ridgeline, and V-6 Accords. Also used in the MDX & RDX with a 93 recommendation. The engines in the Acura's are supposed to be tuned for the higher octane. However, with modern electronic engine controls, that tuning is dynamic, so it will adjust to whatever octane is used. There are folks with Pilots & Odysseys who use the higher octane when towing.

But the main point here should be the use of Top Tier fuel. That is pretty much any name brand & Costco.

horseshoez

iTrader: (2)

I know lots of folks advocate for Top Tier fuel; however, there really isn't any benefit, short term or long, from using any fuel which meets the minimum fuel standards in the U.S. and Canada. Long story short, Top Tier fuel is more of a marketing gimmick than anything.

egads

Top Tier is actually an additive package, like techron. My sister in law, who is the very definition of cheap, would always use the cheapest gas she could find.
She ended up paying the difference in having random misfire codes cleared by her mechanic.

horseshoez

iTrader: (2)

Nonsense, no way you can link the issues with your sister in law with non-Top Tier fuel.

vealboy

Could a dirty MAF sensor effect mileage?