[see.lai]

So I don't know what to do anymore and it's getting really pricey on gas these days.

I have a 2002 Acura RSX-S. I used to average 8-10L/100km. Now I'm at about 12-13L every 100km.

I already changed my Air filter, oil change, spark plugs. No I don't drive aggressive. I've started to notice this since september but it hasn't went away.

I have no CEL, no I don't think changing the primary o2 would help. What else could I do?

[UnName]

Winter gas when it gets warmer and they start using summer blend gas you'll see better mileage.

[mb_]

Everyones mileage drop during winter time
Posted via RS Mobile

[GabAlmighty]

Stop complaining, I have a 165L tank and get about 18mpg on the highway. I daily from Port Moody to Abby.

[mqin]

it'll be like this till the weather gets warmer again, heck if I drive my 350 without really warming it up, it'd be at 55L/100km for the first 5-10mins.

[Eros250]

Yea I drive 03 rsx as well, noticed poor mileage during winter as well.:okay:

[Sky_High]

See.lai + sports car............you're surprise your gas mileage is bad? :troll:

[Traum]

Not disagreeing with the poorer winter gas mileage at all, but with my pos beater, I'm only seeing ~10 - 15% reduction in my gas mileage, whereas the OP is seeing a 30 - 50% increase.

Sounds pretty crazy if you ask me. Does the OP mostly only do short drives?

[q0192837465]

O2 sensor?
Posted via RS Mobile

[PJ]

pcv valve is often overlooked
fuel filter too

[see.lai]

I'm pretty sure winter gas doesn't affect it that much. Last year around this time, I had 9-10L/100km. So I don't think that would affect it.

I noticed this change around september, so I don't think this "winter" gas would be in effect at that time.

Like I said though, the CEL isn't showing, why bother with the O2?

Thanks, I will check pcv and fuel filter.

---

Most are of my drives haven't really changed. Usually 15km each trip. Not sure if that is considered a short drive or not.

[godwin]

Because O2 sensor can be sticky and it still will not have a CEL. It is usually in the marginal scenarios like this. I don't know about Honda/Acura's diagnostics tools but BMW's diagnostic headunits can show the reading changes while the car is being driven. If the sensor reading is not changing as quickly, it is time to change. CEL means failure.. not necessarily non optimal working conditions.

[QUOTE=see.lai;8151885]
Like I said though, the CEL isn't showing, why bother with the O2?

---

[DavidNguyen]

Suurprised no one has said this. Check the tire pressure.
Posted via RS Mobile

[PJ]

Do you have a CAI?

[6o4allmotor]

Lazy 02 sensor im betting
Posted via RS Mobile

[S1 S2]

Running winter tires?

I'm still getting close to 400km a tank
Posted via RS Mobile

[dared3vil0]

My gas mileage has tanked since winter gas/tires... Getting 11-12L/100KM now, Was getting ~9.2 before winter gas/tires. May just be that

[FerrariEnzo]

Problem Solved..

Jeff Dunham - Blue Prius - YouTube



:troll:

[see.lai]

Thanks for the help guys.

I checked tire pressure bi-weekly. I have a short ram intake, but that's not really the point because I had way better mileage last year. Everything is the same, tires are the same as last year.

I will check the O2 as well then. I just didn't want to buy and replace if it wasn't the problem.

[ts14]

check plugs and oil, make sure your trans oil is in good shape otherwise change it out.
you already checked tires but also make sure that your bearings are in good shape and that your brakes are sticking.

you cat also clogs slowly over time but i wouldn't recommend changing it until you blow out your o2 sensors.

check all you belts and pulleys to see if anything is causing extra restriction and clean out air filter.

[|<e|_]

Running winter tires?

I'm still getting close to 400km a tank
Posted via RS Mobile

Driving hard buddy? My sister gets about 480km - 500km+ on hers...then again she has a feather foot

[JesseBlue]

Do you have a fat gf?
Posted via RS Mobile

Kidding aside ... I have the same issue....:(

[4444]

the chances that it's winter vs. summer difference is minimal - this is a huge decrease in economy.

the winter/summer argument is also slightly nullified by saying that colder air in winter makes for higher O2 density, thus increasing economy (hence why so many have CAI)

likely a sensor is bad/needs cleaning, so go to a shop accordingly if you don't know your sensors/how to test/clean them

[vantrip]

My fuel economy improves by 1L/100km in winter when I put stock wheels and tires on :troll:

[FRStan]

I recently took my fuel injectors out and cleaned it, getting much better mileage.

[dared3vil0]

the chances that it's winter vs. summer difference is minimal - this is a huge decrease in economy.

the winter/summer argument is also slightly nullified by saying that colder air in winter makes for higher O2 density, thus increasing economy (hence why so many have CAI)

likely a sensor is bad/needs cleaning, so go to a shop accordingly if you don't know your sensors/how to test/clean them

By the same token that higher 02 density increases efficiency, It also increases drag on the car itself... Therefore DECREASING economy. :suspicious:

[gars]

the chances that it's winter vs. summer difference is minimal - this is a huge decrease in economy.

the winter/summer argument is also slightly nullified by saying that colder air in winter makes for higher O2 density, thus increasing economy (hence why so many have CAI)

likely a sensor is bad/needs cleaning, so go to a shop accordingly if you don't know your sensors/how to test/clean them

I would've thought that the higher O2 density would mean higher fuel consumption because the ECU would use more fuel with the extra O2.

[4444]

I would've thought that the higher O2 density would mean higher fuel consumption because the ECU would use more fuel with the extra O2.

that's not how it works - to travel in the same manner, you would use less fuel as you are rich in O2

otherwise, why would you put a CAI in? its to get more power, due to higher efficiency, etc. so - taking the position that you wouldn't use the extra power, you would be more efficient, hence less fuel

[MindBomber]

Thanks for the help guys.

I checked tire pressure bi-weekly. I have a short ram intake, but that's not really the point because I had way better mileage last year. Everything is the same, tires are the same as last year.

I will check the O2 as well then. I just didn't want to buy and replace if it wasn't the problem.

The 02 sensor on an RSX is rather expensive (by Honda/Acura standards).

If you have basic mechanical skills and can spare an hour or three; I would suggest removing and cleaning the IACV, TB and 02 sensor with carb cleaner or gasoline. Often a significant improvement in fuel consumption can be achieved this way, and it's virtually free. If you don't see a significant improvement, I'd suspect a failing 02.

[S1 S2]

Driving hard buddy? My sister gets about 480km - 500km+ on hers...then again she has a feather foot


Think I can get that too with stock cat back :badpokerface:

Is your sister selling her car anytime soon?

[TypeRNammer]

One of the ep3 people I know had a faulty o2 sensor, even though the check engine light didn't come on.

It was the first thing I suspected since it was only getting 340km per tank :heckno:

[Ronith]

clean ur maf

[S1 S2]

Alignment?

[PJ]

that's not how it works - to travel in the same manner, you would use less fuel as you are rich in O2

otherwise, why would you put a CAI in? its to get more power, due to higher efficiency, etc. so - taking the position that you wouldn't use the extra power, you would be more efficient, hence less fuel

Wut.

With a CAI, your MAF would sense more air flow, so your car uses more fuel to compensate for that extra air.
The extra air doesn't "take the place" of fuel.

CAI = more HP. not better MPG.

[4444]

Wut.

With a CAI, your MAF would sense more air flow, so your car uses more fuel to compensate for that extra air.
The extra air doesn't "take the place" of fuel.

CAI = more HP. not better MPG.

nope, CAI = colder air = denser O2 in the air

it has nothing to do with airflow (that's not true, you do also get more airflow, assuming your stock system is low-flow, as most older american cars used to be, but that only helps give you MORE power)

higher O2 density in your air means more efficient burn of your fuel = more power from the same amount of fuel, vis-a-vis, less fuel used for the same performace

[tiger_handheld]

for a little while i was getting 11/12L / 100km (used to get 9.5/10L). Dumped in a bottle of Chevron fuel cleaner and now i'm back to 9.5/10 range.

[Ronith]

i think ur flux capacitor needs more blinker fluid

you can get a new flux capacitor here:

EB Enterprises 121G - Flux Capacitor | O'Reilly Auto Parts (http://www.oreillyauto.com/site/c/detail/EB00/121G.oap)

[PJ]

nope, CAI = colder air = denser O2 in the air

it has nothing to do with airflow (that's not true, you do also get more airflow, assuming your stock system is low-flow, as most older american cars used to be, but that only helps give you MORE power)

higher O2 density in your air means more efficient burn of your fuel = more power from the same amount of fuel, vis-a-vis, less fuel used for the same performace

Are you basing this info from the box of your intake?

After the MAF, your air gets restricted by the throttle plate. So the only time you'd somewhat get "better" mileage with a CAI is when your throttle's wide open. This is how the intake manufacturers can make these claims of "better" mileage... But if you're throttle's wide open, you're likely on a highway... which you'd get better mileage on anyways.

The CAI mileage difference with city driving will be minimal. And by minimal, I mean your mileage will be slightly lower.

Sure, MAYBE even for the first week or so it might be a tad better, but ultimately your ECU will reset itself and default to "more air = more fuel."

Unless you have your system and ECU tuned along with your CAI specifically for better mileage, there is just no way a CAI alone can give you better mileage. More power, yes. But more mileage just doesn't make sense.

[4444]

Are you basing this info from the box of your intake?

After the MAF, your air gets restricted by the throttle plate. So the only time you'd somewhat get "better" mileage with a CAI is when your throttle's wide open. This is how the intake manufacturers can make these claims of "better" mileage... But if you're throttle's wide open, you're likely on a highway... which you'd get better mileage on anyways.

The CAI mileage difference with city driving will be minimal. And by minimal, I mean your mileage will be slightly lower.

Sure, MAYBE even for the first week or so it might be a tad better, but ultimately your ECU will reset itself and default to "more air = more fuel."

Unless you have your system and ECU tuned along with your CAI specifically for better mileage, there is just no way a CAI alone can give you better mileage. More power, yes. But more mileage just doesn't make sense.

Ok, whatever you think