05 Accord 2.4L - MPG

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buster

buster

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I've noticed that I'm only getting about 23-25 mpg in the Honda now. My driving is 50/50 Highway/City. I average 80 mph on the highway, and maybe 1-4 wOT's daily.

Maintenance is all up to date. Car has 164k miles. Plugs have been changed, and fuel system cleaner used regularly. The car runs exceptionally well.

Does anyone think replacing the coil packs, primary o2 sensor and cleaning the MAF would help pick up a few mpg? Do these parts work fine until they set off a code, or do they gradually degrade over time? I was thinking of replacing all of the above but it may be a complete waste of money. Thanks in advance.
 
Primary O2 sensor will likely be the biggest factor in MPG if its getting old and sick. The coil packs and that unless they're misfiring will likely make no change. Cleaning the MAF could have an effect though, but probably less then the O2 sensor.

Make sure your tires are properly inflated to the maximum, they can have a huge effect on things too.

Your O2 sensor can get "lazy" and not throw a code, sure. My car the CEL would come on and off at seemingly random intervals because the O2 sensor was finally out just far enough to trigger it every few months. I changed it and probably gained an MPG or two. I also overinflate my tires and things though, so I never really gave it a long enough timespan to truly see how much the O2 effected MPG.
 
Originally Posted By: RiceCake
Primary O2 sensor will likely be the biggest factor in MPG if its getting old and sick. The coil packs and that unless they're misfiring will likely make no change. Cleaning the MAF could have an effect though, but probably less then the O2 sensor.

Make sure your tires are properly inflated to the maximum, they can have a huge effect on things too.

Your O2 sensor can get "lazy" and not throw a code, sure. My car the CEL would come on and off at seemingly random intervals because the O2 sensor was finally out just far enough to trigger it every few months. I changed it and probably gained an MPG or two. I also overinflate my tires and things though, so I never really gave it a long enough timespan to truly see how much the O2 effected MPG.


+1.

Thanks for saving me the typing time.
thumbsup2.gif
 
At that mileage the MAF should only need a cleaning but the pre-cat o2 is exposed to constant heat and carbon from the exhaust so replacing it would not be a bad idea. You probably already know this but only use denso, don't use the bosh universals.
 
^ Thanks! I did not know that, but will definitely stick with the denso.
 
Do everything you said in your post. And driving 80mph will definitely affect your mpg.

My Accord V6 6-speed gets 26mpg mixed, you should definitely be getting better.
 
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What where you get for MPG's before you noticed this. You can expect a 10% loss for winter blend fuel. Did you recently get new tires. They might have more rolling resistance. When I had my '05 Accord when I got different tires mileage went from 30 to 27 MPG and about 25 MPG in the winter months. Not saying this is it but something to consider.
 
Try driving 65 and time warp back to the summer and that should be near 28mpg

I dont see that as severely low enough to be a possible mechanical failure.

80mph for me resulted in a 4mpg decrease and I also lost 1-2 to winter tires and some to winter itself.
 
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Your mileage sounds reasonable, and similar to the 05 Accord 4cyl that I deal with.

Winter gas, warming up the engine, defrost/AC, lower air pressure in the tires, cold fluids, all contribute to a loss of mpg in the winter.

Its pretty easy to clean the MAF, might as well do it if you're antsy about it. I'd wait till spring and re-check your mpg before messing with any of the other stuff.
 
mileage sounds about right.

Thing to consider RE: gaining a bit of mileage (assuming that you have experienced a bit of mileage loss recently):

(1) winter blend: typically you get around 10 % more or less loss..there's nothing you can do about it.

(2) longer warm up time. This is inevitable due to the fact that colder days, engine tends to take a bit longer to warm up and that wastes gas as the engine stay on open loop mode with richer F/A mixture as it warms up (similar to the manual/auto choke back in carb days). Try driving it to get it warm up faster.

Also: if you haven't replace your thermostat, consider replacing it with a factory fresh unit. sometimes, when thermostat gets old, it tends to get lazy or cannot close completely, which leads to extended warm up time.

(3) most post 03 vehicles incl. Honda, have A/C on when turn to front windshield defrost. Unless you are willing to do some surgery on your control panel to remove that wiring on the selector switch (so as to disconnect the A/C on while front windshield defrost), otherwise, that would eat up an additional 7~15% fuel.

(4) tire pressure.

(5) driving pattern. Frequent short trips during winter time will definitely eat into your economy (due to more frequent cumulative warm up time for the engine, which, again, uses fuel. See if you can combine a few short trips by planning ahead so as to shorten the unnecessary idling/restarting and warm up phase.

Good luck.

Q.
 
Originally Posted By: LeakySeals
You probably already know this but only use denso, don't use the bosh universals.



+++++ 11111111111111111111

we had a pontiac vibe at the shop ( Toyota Matrix clone ), and despite my repeated suggestions that he should order a Denso, he chose to order the Bosch OE fit. Car was back in the shop 2 days later, Heater Circuit on O2 sensor non functional. Another Bosch later, this time it made it a week before we saw it again. Driveability problems, no CEL. Finally gives in and orders a Denso, problem solved.
 
Most cars start to lose a lot of mpg once you go over about 70 mph and then you add in all other variables ....it starts to make sense
 
I have a '03 2.4 w/160+ and this last october did 40mpg and 39mpg going the speed limit 65/55 on my w/e trip 250mi. ea. way to cabin..never let the rpm over 2400 getting up to speed and tires @38psi

normal trip is 75/65mph with 32psi. and 34mpg.
 
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