ROK801

so recently ive been getting some really terrible gas mileage.

i only run 91+ octane, my air cleaner is clean, my o2 sensor is reading just fine, my fuel filter is brand new, just changed my oil 600 miles ago, and im still getting horrible gas mileage.

i imagined when i changed the fuel filter that id get a little worse mileage since its flowing freely instead of a little clogged... but im seriously getting like 16mpg on the freeway. its ridiculous.

my plugs and wires have maybe 5000 miles on them.

i dont get it...

any help would be great.

Cray91

I assume this iss the 97 DX in your sig. That is really weird that you are getting that poor mileage.

I would seriously thing you did the math wrong. The indicators would be in the plugs or filter ect. if they all check out, then tough to say. Have you been smelling gas at all? a physical leak might be the culprit with that much fuel being lost. That is like half the mileage you should be seeing.

WayQuiz

if you have a stock 97 dx like in your sig you should be using 87 octane. the higher octane mostl likely isn't helping.

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wayquiz &raquo;</TD></TR><TR><TD CLASS="quote">if you have a stock 97 dx like in your sig you should be using 87 octane. the higher octane mostl likely isn't helping.</TD></TR></TABLE>

i always run 91...
habbit.

but either way, it shouldnt be the cause of such poor fuel mileage...
i cant figure it out.

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cray91 &raquo;</TD></TR><TR><TD CLASS="quote">I assume this iss the 97 DX in your sig. That is really weird that you are getting that poor mileage.

I would seriously thing you did the math wrong. The indicators would be in the plugs or filter ect. if they all check out, then tough to say. Have you been smelling gas at all? a physical leak might be the culprit with that much fuel being lost. That is like half the mileage you should be seeing.</TD></TR></TABLE>

no fuel leak...
i thought someone had cyphened my gas at first...
i park in the same spot at home and at work, nothing is dripping anywhere.
it would leak as soon as i turned my car on and let it idle for a bit, i get nothing. i did find out that i have a small crack in my head gasket though... hah.

tpr

How did you check the miles per gallon (MPG). The only accurate method is to fill the tank and reset the trip meter. The next time you fill the tank write down the miles driven. Then divide the miles driven by the gallons to fill the tank. Any other method is flawed as the honda fuel gauges are not linear. That year should get around 30-32 around town and 35-36 on the highway.

portfl0w

iTrader: (1)

how do you konw your o2 sensors are reading correctly? if your burning to much fuel your sensors should be the first to know, something in your engine is inneffeicient or you have drag causing resistance and increasing load, check fuel pressure, intake and exhaust flow, compression/leakdown, brake adjustment, try running 87...

AbitAvenger

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tpr &raquo;</TD></TR><TR><TD CLASS="quote">How did you check the miles per gallon (MPG). The only accurate method is to fill the tank and reset the trip meter. The next time you fill the tank write down the miles driven. Then divide the miles driven by the gallons to fill the tank. Any other method is flawed as the honda fuel gauges are not linear. That year should get around 30-32 around town and 35-36 on the highway.</TD></TR></TABLE>

please explain what you mean by the gauges not being linear.

gapergurlie_18

did u mess with any hoses??

Deemeetree

How is your timing and catalytic converter?

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by portfl0w &raquo;</TD></TR><TR><TD CLASS="quote">how do you konw your o2 sensors are reading correctly? if your burning to much fuel your sensors should be the first to know, something in your engine is inneffeicient or you have drag causing resistance and increasing load, check fuel pressure, intake and exhaust flow, compression/leakdown, brake adjustment, try running 87...</TD></TR></TABLE>

first off, im not getting a code...
but i had one of my friends run a diagnostic check and nothing was out of the ordinary...

i put 87 in today. ill see how it goes.

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Deemeetree &raquo;</TD></TR><TR><TD CLASS="quote">How is your timing and catalytic converter?</TD></TR></TABLE>

thats next on my list, but i idle fine... timing cant be too far off it is.

im about to hollow out my cat...
it could be clogged up a bit.
i started to think it was my cat...
on the freeway im getting 22mpg-ish...
it seems like i have to give it a lot more peddle on the freeway than normal.
its gotta be restricted somewhere.

tpr

The fuel gauge will sit for a long time near full then begin to move down toward the middle (half full), where it reads most accuracly, then as you approach empty it moves a lot faster. The MPG has not changed just the rate at which the gauge responds to gallons used is not linear. Its only a little off but enogh so using the fuel gauge to track gallons used is not an accurate way to calculate MPG.

bmw626

my MAP sensor was bad and i didn't even get a CEL for it and i was doing 14MPG MAX with a d15b7 and an s20 tranny and then i put a new one in there and now i am doing about 36MPG... just a thought, you might wanna check it out

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tpr &raquo;</TD></TR><TR><TD CLASS="quote">The fuel gauge will sit for a long time near full then begin to move down toward the middle (half full), where it reads most accuracly, then as you approach empty it moves a lot faster. The MPG has not changed just the rate at which the gauge responds to gallons used is not linear. Its only a little off but enogh so using the fuel gauge to track gallons used is not an accurate way to calculate MPG.</TD></TR></TABLE>

i ran it from completely full to completely empty(sputtering until i finally had to pull over) and went from my odometer mileage...

portfl0w

iTrader: (1)

just cuz yoru not gettin a mil doiesnt mean theres not a problem cuz there clearly is. what kind of diagnostics are you talking about? did he use an osciliscope on the o2 sensors? regular voltage readings arent reliable as they can not read the 02 sensor correctly, they jsut tell you if thers voltage or not you need an o-scope to see the sine wave. i reccomend more testing of sensors.

portfl0w

iTrader: (1)

and changing your fuel filter will increase mileage because you were starving the engine of fuel so the o2 sensors pick that up and the ecm increases injector duty cycle to compensate (more fuel), if your car is not runnin as intended it will always get worse gas mileage never better.

ROK801

im just changing everything out...
with gas prices the way they are(and getting worse) i dont even want to deal with it...

getting a new cat and new o2 sensors...
my cat is a little clogged. it cant hurt to change em...

Dwight Schrute

there is no point in running 91octane... you might as well give the extra money to me

ROK801

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drewthomas14 &raquo;</TD></TR><TR><TD CLASS="quote">there is no point in running 91octane... you might as well give the extra money to me</TD></TR></TABLE>

if youll read what i posted afterwards i quit running it.
ps. its $.10 more for premium... a whole dollar.
i wasnt stressing it.

Jedi_Sol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ROK801 &raquo;</TD></TR><TR><TD CLASS="quote">

if youll read what i posted afterwards i quit running it.
ps. its $.10 more for premium... a whole dollar.
i wasnt stressing it.</TD></TR></TABLE>

Be that as it may, but what did you used to think you were gaining by using 91octane? (yes i do realize you stopped using 91)

ROK801

cleaner fuel...
definitely not power...

Jedi_Sol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ROK801 &raquo;</TD></TR><TR><TD CLASS="quote">cleaner fuel...
definitely not power...

</TD></TR></TABLE>

Well, you got half of it right.

The difference between octane ratings is purely based on how much it will compress before preignition. THATS IT, COMPRESSION, COMPRESSION, COMPRESSION.

If you want cleaner burning fuel, the difference lies between the different gas companies. Shell (v-power) and Chevron (techron) will have cleaner burning fuel because of the amount of detergents they put in their gasoline that meet and exceed the federal regulation... when compared to places like "Thrifty Gas" that put the bare minimum amount of detergents. Chevron puts the same amount of techron in all of thier octane ratings.

fwdtamiya

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jedi_Sol &raquo;</TD></TR><TR><TD CLASS="quote">Chevron puts the same amount of techron in all of thier octane ratings.</TD></TR></TABLE>

belly-eg6

it could be your cat if that gets really clug it can make u lose gas milage'