[Midnighter427]

Hey guys, I’ve been on a 6 month journey to try an figure out why I’m getting bad mpg on my 2013 accord v6 manual. So far I’ve done my brake pads/rotors, new tires, alignment, balancing, air filter and cabin air filter changes. I also use 0w-20 oil to do my oil changes but living in Toronto I’m getting 22L /100km (Roughly 10mpg). I’m wondering if this is what I should be getting and if it’s regular or not to get this mpg. If not, what could potentially be wrong that I may be overlooking? I’ve done three different diagnostics at 3 different shops including Honda which provided a report with all data showing everything is fine. Every place has done a scan along with checking the tires. I’m somewhat hopeless and don’t know where to go from here. Just trying to figure out if my expectation is just too high for the mpg or if there’s actually something wrong. And if something is wrong then where to go from there.

I also get good mileage on other v6 cars so I know it’s not my driving that’s causing it.

 

[WiiMaster]

What mileage? O2 sensors can make a huge difference on the J series.

How are your short and long term fuel trims? It's probably a good idea to invest in a scanner that can read the live data.

 

[Midnighter427]

What mileage? O2 sensors can make a huge difference on the J series.

160k km

How are your short and long term fuel trims? It's probably a good idea to invest in a scanner that can read the live data.

Do you have a discord I can dm you at or anything of the sort?

 

[Spacedave]

From the long term trims, it seems you are running rich. Perhaps your fuel injectors do not shut off completely and need to be cleaned. A bottle of Techron might clear it up; MAP sensor also might need to be cleaned, inexpensive if you do it yourself..

 

[OmegaSupreme]

Your fuel trims look good to me. Are you keeping your RPMs under 3k when driving in the city? Do you have a tune?

For reference: Long Term Fuel Trim and Short Trim Fuel Trim - INTEGRATED SOLUTION TRADING

 

[sequoiasoon]

From the long term trims, it seems you are running rich. Perhaps your fuel injectors do not shut off completely and need to be cleaned. A bottle of Techron might clear it up; MAP sensor also might need to be cleaned, inexpensive if you do it yourself..

I never noticed a difference using Techron. I found BG 44K to be much better for me. Others on BITOG also recommend Gumout with REGANE.

OP- you say new but what tires? Stock size? Stock rims? Larger rims normally have more weight and more needed to get moving and stopping. Any other mods like "performance" air filters? With the new brakes is parking brake releasing all the way? Some on here reported rusting of the mechanisms even though you use everyday (happened to me on my manual Sonata and Corolla also). How much stuff in the trunk?

What is your shift point around town and how fast do you get there? I enjoy driving manual and in 1, 2, 3 might find 6500rpm approaching quickly but mine is 4cyl. Once on the highway 6 gear cruise is with traffic.

9 years in Canada - any leaks underneath where you might smell fuel from corrosion of lines? I don't know if Honda has the same, my Corolla had a bad temperature sensor when cold but it was only for the ECU not fans. It would run like garbage at start from the extra fuel but no trouble codes.

 

[Midnighter427]

From the long term trims, it seems you are running rich. Perhaps your fuel injectors do not shut off completely and need to be cleaned. A bottle of Techron might clear it up; MAP sensor also might need to be cleaned, inexpensive if you do it yourself..

Would it be better to replace them or would cleaning them be just as good?

I never noticed a difference using Techron. I found BG 44K to be much better for me. Others on BITOG also recommend Gumout with REGANE.

OP- you say new but what tires? Stock size? Stock rims? Larger rims normally have more weight and more needed to get moving and stopping. Any other mods like "performance" air filters? With the new brakes is parking brake releasing all the way? Some on here reported rusting of the mechanisms even though you use everyday (happened to me on my manual Sonata and Corolla also). How much stuff in the trunk?

What is your shift point around town and how fast do you get there? I enjoy driving manual and in 1, 2, 3 might find 6500rpm approaching quickly but mine is 4cyl. Once on the highway 6 gear cruise is with traffic.

9 years in Canada - any leaks underneath where you might smell fuel from corrosion of lines? I don't know if Honda has the same, my Corolla had a bad temperature sensor when cold but it was only for the ECU not fans. It would run like garbage at start from the extra fuel but no trouble codes.

Haven’t found any leaks so far. I upshift between 2.5-3k and the everything on the car is stock apart from aftermarket 18 inch rims and I have new 255/45/r18 summer tires that were put on a few weeks ago. The parking brake works fine as I haven’t really found anything that isn’t working so far. Hope that helps 😊

Your fuel trims look good to me. Are you keeping your RPMs under 3k when driving in the city? Do you have a tune?

For reference: Long Term Fuel Trim and Short Trim Fuel Trim - INTEGRATED SOLUTION TRADING

Always below 3k rpm and it hasn’t been tuned so far. The car is bone stock

I’d like to include that the car kills a lot of gas on idle, at times where I’m waiting for a friend occasionally for 20 minutes or so the fuel gauge will go down by a bit where I can see it solely from my eyes. The range also goes down by like 30km and the l/100km shoots up. I know this is not accurate as the range is just an ecu reading but I thought I should include it if it helps understand.

I never noticed a difference using Techron. I found BG 44K to be much better for me. Others on BITOG also recommend Gumout with REGANE.

OP- you say new but what tires? Stock size? Stock rims? Larger rims normally have more weight and more needed to get moving and stopping. Any other mods like "performance" air filters? With the new brakes is parking brake releasing all the way? Some on here reported rusting of the mechanisms even though you use everyday (happened to me on my manual Sonata and Corolla also). How much stuff in the trunk?

What is your shift point around town and how fast do you get there? I enjoy driving manual and in 1, 2, 3 might find 6500rpm approaching quickly but mine is 4cyl. Once on the highway 6 gear cruise is with traffic.

9 years in Canada - any leaks underneath where you might smell fuel from corrosion of lines? I don't know if Honda has the same, my Corolla had a bad temperature sensor when cold but it was only for the ECU not fans. It would run like garbage at start from the extra fuel but no trouble codes.

Trunk is also empty like literally empty

 

[OmegaSupreme]

Always below 3k rpm and it hasn’t been tuned so far. The car is bone stock

What octane fuel are you running?

 

[Midnighter427]

What octane fuel are you running?

87. The owners manual says 87 or higher. I’m assuming 87 is okay.

 

[sequoiasoon]

Check the weight of the aftermarket rims if possible as compared to what came stock, pounds matter. The summer tires might not be a lower rolling resistance version but sticky performance, trade offs.

I would include doing new plugs if not done, a thorough TB cleaning, possibly a BG EPR motor flush, and a couple 3-4 tankful's of BG 44k (full tank to almost empty), careful MAF cleaning and check for any obstructions on intake parts from debris or creatures.

Avoid the idling it's a killer. Think all the new auto stop/start vehicles that shut down to save fuel. Started in Europe a while back and their fuel is a lot more expensive. Like WiiMaster said, possibly change O2 sensors.

Do an exact mileage calculation, old school paper/pen/calculator. Fill up at same way either 1st click after slow fill or whatever that is. Mileage and L/Gal then math. If not filled the same way all the time then it's a guess. My cars all have a small notepad in them. Date, Mileage, gallons and any maintenance done. My kids know and do it also. Fill it, every time, never $20 worth etc.

 

[Midnighter427]

Check the weight of the aftermarket rims if possible as compared to what came stock, pounds matter. The summer tires might not be a lower rolling resistance version but sticky performance, trade offs.

I would include doing new plugs if not done, a thorough TB cleaning, possibly a BG EPR motor flush, and a couple 3-4 tankful's of BG 44k (full tank to almost empty), careful MAF cleaning and check for any obstructions on intake parts from debris or creatures.

Avoid the idling it's a killer. Think all the new auto stop/start vehicles that shut down to save fuel. Started in Europe a while back and their fuel is a lot more expensive. Like WiiMaster said, possibly change O2 sensors.

Do an exact mileage calculation, old school paper/pen/calculator. Fill up at same way either 1st click after slow fill or whatever that is. Mileage and L/Gal then math. If not filled the same way all the time then it's a guess. My cars all have a small notepad in them. Date, Mileage, gallons and any maintenance done. My kids know and do it also. Fill it, every time, never $20 worth etc.

My last fill up I did 58L and ran 283 km until empty by noting down before and after odometer mileage reading. 58 / 283 * 100 = 20.5L /100KM which converts 11.5MPG strictly city. I’m running EuroDesign 18x8 rims that came with the car with these specs. I’ve been spending money trying to fix the issue so I don’t want to randomly throw money at parts without figuring out the cause of the issue. But I’m definitely getting the spark plugs replaced soon regardless. I’m just debating whether to do the ignition coils, fuel injectors, maf and o2 sensors along with it in terms of replacement if they could be causing the issue.

 

[adomzz]

Hey guys, I’ve been on a 6 month journey to try an figure out why I’m getting bad mpg on my 2013 accord v6 manual. So far I’ve done my brake pads/rotors, new tires, alignment, balancing, air filter and cabin air filter changes. I also use 0w-20 oil to do my oil changes but living in Toronto I’m getting 22L /100km (Roughly 10mpg). I’m wondering if this is what I should be getting and if it’s regular or not to get this mpg. If not, what could potentially be wrong that I may be overlooking? I’ve done three different diagnostics at 3 different shops including Honda which provided a report with all data showing everything is fine. Every place has done a scan along with checking the tires. I’m somewhat hopeless and don’t know where to go from here. Just trying to figure out if my expectation is just too high for the mpg or if there’s actually something wrong. And if something is wrong then where to go from there.

I also get good mileage on other v6 cars so I know it’s not my driving that’s causing it.

I have the same engine in my EXL Coupe and if I just cruise on the interstate at about 80 without frequent downshifts I can get about 28.5MPG - with 175k miles running Amsoil 0w20 and Sunoco 93 gas. However its easy to only get 21-22 as well if you run it hard. Around town, Im usually about 17-21 consistently and that's with original O2 sensors and my AC is always on too.. Not sure what your issue is. Do you need plugs or an air filter? Or just driving style and shift points in general.

 

[Midnighter427]

I have the same engine in my EXL Coupe and if I just cruise on the interstate at about 80 without frequent downshifts I can get about 28.5MPG - with 175k miles running Amsoil 0w20 and Sunoco 93 gas. However its easy to only get 21-22 as well if you run it hard. Around town, Im usually about 17-21 consistently and that's with original O2 sensors and my AC is always on too.. Not sure what your issue is. Do you need plugs or an air filter? Or just driving style and shift points in general.

Your reply gives me hope that there’s room for better mileage. I don’t drive the car hard and whenever I’m driving my friends 323i (manual) I’m getting better mileage and even on an is350(auto) I’m also getting better in the city I’m getting good mileage so I know it’s not really me. Does the 93 make a difference? I never put more than 91 in my car and I only did that once but if putting 93 is the difference I’ll definitely do that instead. How big are the roads in the town you drive in? Toronto is like the New York equivalent of traffic, but then again even in less crowded towns I’m still getting poor mileage.

 

[OmegaSupreme]

87. The owners manual says 87 or higher. I’m assuming 87 is okay.

I think 87 is the cause of your low gas mileage. Yes, you can run 87 but it will cost you power and mpg. I'd never run 87 unless I have to. Try running two tanks of 93.

 

[WiiMaster]

Huh? If your vehicle is tuned to run on 87, it is not going to have a negative impact by using it...

 

[Midnighter427]

I think 87 is the cause of your low gas mileage. Yes, you can run 87 but it will cost you power and mpg. I'd never run 87 unless I have to. Try running two tanks of 93.

I’m running 93 right now and I’m getting the same looool. Done 143 city so far and I’ve killed nearly half looool

It says

Huh? If your vehicle is tuned to run on 87, it is not going to have a negative impact by using it...

87 or higher recommended. I just put 93 and I’m getting the same stuff so far in terms of mileage.

 

[OmegaSupreme]

Huh? If your vehicle is tuned to run on 87, it is not going to have a negative impact by using it...

Yes, you can run 87 but you wont be getting the most out of the J35. The ecu will advance the timing more with higher octane fuel thus more power and better mpg.

 

[Midnighter427]

Yes, you can run 87 but you wont be getting the most out of the J35. The ecu will advance the timing more with higher octane fuel thus more power and better mpg.

How come I’m getting similar mileage rn then

 

[OmegaSupreme]

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How come I’m getting similar mileage rn then

It might be the rims. You are getting worse mpg then me. That's with stock tires/rims, bolt-ons, and my target AF set at 14.0. I'm getting around 13mpg city and 28ish mpg highway.

 

[Midnighter427]

[

It might be the rims. You are getting worse mpg then me. That's with stock tires/rims, bolt-ons, and my target AF set at 14.0. I'm getting around 13mpg city and 28ish mpg highway.

Don’t you think 13 is bad or is that just how it’s supposed to be? 13 isn’t far off from 11