[dtruong]

Hey Everyone, quick question for y'all. My girlfriend just recently got a 2014 Honda Accord Coupe V6 with right around 76k miles. She just filled up for the first time and reset her Trip A. So far she has driven 62 miles and there is about 6/10 of a tank left. She reset her MPG the same time and its sitting right around 22mph so shes not beating on the vehicle or anything. It also shows a range of 240 left. Any idea what could be wrong? It had pretty good service records (but only oil changes, tire rotations etc...) but my only current guess is that she needs a spark plug service and maybe a fuel system clean? Would appreciate any help!

Her driving is mixed between city And Highway and she does not drive aggressive at all. Keeps it in ECO mode the entire time. Doing the calculations as of right now and she’s only getting about 11 MPG.

 

[Justinga99]

How many tanks has she went through? Are you doing the full calculations correctly? Start off with trip at zero with a full tank. Drive to empty. Fill up. Divide trip total by gallons added.

If she just bought it, it's possible the battery was disconnected for service work. That will mess up the in dash mpg calculator until it has time to relearn driving habits and adjust itself.

11mpg is really bad. If all calculations are done correct, you have something else going on. Most likely worse than just spark plugs and dirty fuel system.

 

[AccorDokken]

I'd check the air filter first. If that's clean she might have seized caliper.

 

[WiiMaster]

Where are you located? Winter blend gas can also have an effect though nothing significant to get you MPG that low.

If you have an IR temp gun, checking for a seized caliper is really easy. After going for a drive, check the temperatures are 4 wheels. If you have a stuck caliper, one wheel will be noticeably hotter than the rest (though it is normal for the fronts to be warmed than the rears so don't let that throw you off).

 

[Blackheart]

First, you cannot accurately estimate the MPG by looking at the gauge. You need to fill the car up on level ground, and make sure it's full and not simply cutting off early. Then, you need to operate the vehicle until such time as you re-fill. Ideally, you'd refill at the same pump (although I know that's not very practical). Next, DO THE MATH. Miles travelled divided by gallons used = MPG. Secondly, just because the average speed is "only 22 MPH" doesn't tell you anything useful. When a car is idling but not moving, it is getting ZERO MPG and averaging ZERO MPH.
Do the first thing correctly, and then see where you are actually starting. You'll have to start over and make sure the initial fill is actually full, that the car was at least on a level surface, too.

 

[dtruong]

Thank you for the input everyone. As for the 22 mph I apologize on my end it was supposed to say its showing as 22 MPG. I am going to have her go back to the drawing board and do the math on a couple of fill ups here and see what happens. I will check back in in a couple weeks or so!

 

[OmegaSupreme]

City driving will lower your average mpg. Both auto and manual do better on the highway. Running higher octane helps too.

 

[scar_cle]

I'd check the air filter first. If that's clean she might have seized caliper.

Ill go with Caliper too, Mine was so hot seized up driving on interstate 90- through NY, PA, OH by the time I got home that wheel was literally smoking. The worst burning Metallic smell ever.

 

[shintony]

The fuel gauge in your instrument cluster is not entirely a linear indicator. Best way to measure fuel economy is start counting your mileage when refuel. When you refuel the next time ON THE SAME FUEL PUMP you can use the amount of fuel purchased to calculate.
22mi/us gal is not too bad though.

Where are you located? Winter blend gas can also have an effect though nothing significant to get you MPG that low.

If you have an IR temp gun, checking for a seized caliper is really easy. After going for a drive, check the temperatures are 4 wheels. If you have a stuck caliper, one wheel will be noticeably hotter than the rest (though it is normal for the fronts to be warmed than the rears so don't let that throw you off).

My fuel economy dropped quite a bit during winter but that’s due to denser air (cold) and interior heater. Coolant temperature never reaches 80C unless I drive it for an hour to let interior fully warmed up. I find that turning off the heater before engine temperature raise to 75C can significantly save fuel on cold start.
Luckily I live near the highway so my warm up is fairly quick.

 

[Justinga99]

City driving will lower your average mpg. Both auto and manual do better on the highway. Running higher octane helps too.

Higher Octane is not going to affect fuel mileage.

 

[pastaben]

You gave two MPS numbers, 22 and 11. A V6 seems normal at 22. I don't own a V6, but know people who have. 11 would be bad.

 

[Scorpio8]

Hey Everyone, quick question for y'all. My girlfriend just recently got a 2014 Honda Accord Coupe V6 with right around 76k miles. She just filled up for the first time and reset her Trip A. So far she has driven 62 miles and there is about 6/10 of a tank left. She reset her MPG the same time and its sitting right around 22mph so shes not beating on the vehicle or anything. It also shows a range of 240 left. Any idea what could be wrong? It had pretty good service records (but only oil changes, tire rotations etc...) but my only current guess is that she needs a spark plug service and maybe a fuel system clean? Would appreciate any help!

Her driving is mixed between city And Highway and she does not drive aggressive at all. Keeps it in ECO mode the entire time. Doing the calculations as of right now and she’s only getting about 11 MPG.

Defective (coated, worn out) air fuel ratio / oxygen sensors can also give the engine computer false readings. It may not set a code so check fuel trims with a scan tool as well as the response of the air fuel / oxygen sensors.

 

[Rygrego]

Defective (coated, worn out) air fuel ratio / oxygen sensors can also give the engine computer false readings. It may not set a code so check fuel trims with a scan tool as well as the response of the air fuel / oxygen sensors.

I would be shocked to go through O2 sensors at 76,000 miles.

 

[Scorpio8]

Silicone, combustion by products contamination, etc. Test first if in doubt. Watch the waveform as you introduce extra air, & then more extra "fuel" (carb cleaner should do the trick).

 

[OmegaSupreme]

Higher Octane is not going to affect fuel mileage.

How so when v6 ECU advances timing when you run higher octane fuel? When I had a stock tune, I got better mgp on 93 then I did with 89. That's after the ecu adjusted to the difference.

 

[Blackheart]

How so when v6 ECU advances timing when you run higher octane fuel? When I had a stock tune, I got better mgp on 93 then I did with 89. That's after the ecu adjusted to the difference.

There is only ONE POINT of piston travel at which the spark timing is most efficient. If an 87 Octane allows the spark plug to fire and burn the fuel at the most efficient Air/Fuel ratio at that ONE POINT in piston travel, a higher Octane won't increase efficiency. OTOH, if there is excessive heat in the combustion chamber due to carbon deposits, there will be a tendency to have the ECU "richen" (which serves to cool the combustion chamber) the A/F ratio, which is less efficient. In this case, a higher Octane rating allows the fuel to NOT prematurely ignite due to the high temps, and an increase in efficiency can occur. There are scenarios where higher Octane helps, but, saying a higher Octane allows the ECU to simply "advance the timing" isn't correct. Any engine system that is running the ideal A/F ratio and also advances the timing too far loses efficiency and power.

 

[OmegaSupreme]

There is only ONE POINT of piston travel at which the spark timing is most efficient. If an 87 Octane allows the spark plug to fire and burn the fuel at the most efficient Air/Fuel ratio at that ONE POINT in piston travel, a higher Octane won't increase efficiency. OTOH, if there is excessive heat in the combustion chamber due to carbon deposits, there will be a tendency to have the ECU "richen" (which serves to cool the combustion chamber) the A/F ratio, which is less efficient. In this case, a higher Octane rating allows the fuel to NOT prematurely ignite due to the high temps, and an increase in efficiency can occur. There are scenarios where higher Octane helps, but, saying a higher Octane allows the ECU to simply "advance the timing" isn't correct. Any engine system that is running the ideal A/F ratio and also advances the timing too far loses efficiency and power.

Saying the ECU "advances the timing" is a low level surface conversation answer. I have no intention of diving into the science behind combustion and control theory. Its like saying you get old then you die is wrong. Yeah, there are many factors that lead to person death. Its not just about simply getting old.

 

[Blackheart]

Saying the ECU "advances the timing" is a low level surface conversation answer. I have no intention of diving into the science behind combustion and control theory.

A "low level surface conversation answer" leads the under-informed with the impression that higher Octane rated gas with an ECU that "advances the timing" provides better economy. That's simply not true when timing with lower Octane rated gas achieved spark timing at the ideal point of travel of the piston (which changes slightly depending upon RPMs). The ECU cannot simply "advance timing" for better efficiency unless there were conditions prior to using a higher Octane rated gas that didn't allow the ideal timing and A/F trim to occur simultaneously.