i have a 92 civic hb Si that i bought about a month ago. when i first bought the car and filled up the tank, it ran for 280 miles before i had to refill (which is average i guess, i know of hb's that can run up to 350 to the tank.).

after that first tank, whenever i hit E, i only get 200 miles. i don't know why i would lose 80 miles in under 2 weeks.

my last tank only lasted 175 miles. what could i replace to make my gas mileage better again?

again it's a 92 hb Si with 219k on the motor. i haven't done anything with the motor, it's completely stock.

also, when i have a quarter tank left, the car sputters more than usual when i'm idling. it stops when i fill up the tank. could it be the fuel injectors?

will giving it a tune up or new fuel filter help? the oil was just changed so i don't think that's a problem. thanks

 

dont let it get that low, it could be the fuel pump is tired. O2 sensors, also ignition parts.

 

ck your tire pressure. do you have any recent maintence history on the car? oil changes don't count. sounds like it's prob due for a tune up anyway. plugs,wires,cap, rotor, and fuel filter. get it all taken care of, so you can get on a schedule.

hows the condition of the car? scratch everything i just said and swap a b series into that bitch

 

Prolly needs a nice tune up and some replacement parts

Fuel Pump
Fuel Filter
o2 sensor
plugs and wires
have you ICM checked out as well
also you might want to do a compression check

 

yeah i'm saving up for a b18b right now, but i need the motor running at least until i can swap it.

 

The o2 doesn't play a large role in gas mileage, not anything noticeable anyways.

Don't forget to also check the real basic stuff, oil and plugs.

 

your heading in the right direction at least... whats the game plan from there? any plans to boost it? or is NA what you're looking for? why the ls motor and not a b16 or gsr? just curious. if NA is what you plan on..i only ask this because the ls is subpar to the other two. if you do plan on doin the ls motor, then at least up it to the gsr tranny for a little quicker acceleration and def get some cams too. the ls tranny is haten it and topend sucks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94ls &raquo;</TD></TR><TR><TD CLASS="quote">your heading in the right direction at least... whats the game plan from there? any plans to boost it? or is NA what you're looking for? why the ls motor and not a b16 or gsr? just curious. if NA is what you plan on..i only ask this because the ls is subpar to the other two. if you do plan on doin the ls motor, then at least up it to the gsr tranny for a little quicker acceleration and def get some cams too. the ls tranny is haten it and topend sucks.</TD></TR></TABLE>

that's what i can afford right now, i'm planning on putting a b18c head and then supercharge.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Echelon &raquo;</TD></TR><TR><TD CLASS="quote">The o2 doesn't play a large role in gas mileage, not anything noticeable anyways.

Don't forget to also check the real basic stuff, oil and plugs.</TD></TR></TABLE>

DO NOT Listen to this guy. He doesnt know what he is talking about

If your o2 is going bad and is not reading accurately Then it cannot signal the ecu to control the fuel. Ive seen a Bad o2 and it never threw a CEL. But when the o2 goes bad it can throw its self into a limp mode.. limp mode is basically the ECU covering the motors *** by dumping in extra fuel to be sure that it does not denate and it can affect your ignition as well as your redline. Ive seen this all in front of my eyes ..

Just thought i would clear that up.

 

Yeah the same thing is happenin to me with my 93 civic dx. i use to get better gas mileage but its going down. like 200miles for a full tank. and like i know an after market intake and exhast cant take that much gas or can it? ... ummMmm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMlyfestyle &raquo;</TD></TR><TR><TD CLASS="quote">DO NOT Listen to this guy. He doesnt know what he is talking about

If your o2 is going bad and is not reading accurately Then it cannot signal the ecu to control the fuel. Ive seen a Bad o2 and it never threw a CEL. But when the o2 goes bad it can throw its self into a limp mode.. limp mode is basically the ECU covering the motors *** by dumping in extra fuel to be sure that it does not denate and it can affect your ignition as well as your redline. Ive seen this all in front of my eyes ..

Just thought i would clear that up.</TD></TR></TABLE>

thanks for the info, so do you think i should change the o2 sensor and maybe get a tune up?

 

yes replace the o2 sensor and do a FULL tune up.

Oil change
Plugs/wires/rotor
Fuel Filter
remove your ICM and have it tested

 

my car was doing the exact same thing. it was a dx with 195k on the clock. i swapped in a different motor and now im getting 350 to a tank

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by oo3 &raquo;</TD></TR><TR><TD CLASS="quote">thanks for the info, so do you think i should change the o2 sensor and maybe get a tune up?</TD></TR></TABLE>
Yes, and have them do a top engine cleaning, or get with a can of Seafoam. Ahh, Seafoam.

 

thanks for all the help guys...this site is sooooooo much better than superhonda...all they do is say how stupid you are for not knowing anything and to figure it out yourself...no help at all.

 

don't buy a new o2 yet. Take it out and dunk it in some seafoam and swirl it around. It brought mine back to life.

 

Actually test the O2 sensor according to the shop manual to see if it's lazy. I would not be throwing $100 parts around unless you confirm theyre bad.

What did you do to it to mess it up so quickly? Check the oil level. Just dealt with someone that put 3 qts in but forgot to let the original oil out. Sputtered and idled like **** with terrible gas mileage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shaundrake &raquo;</TD></TR><TR><TD CLASS="quote">Actually test the O2 sensor according to the shop manual to see if it's lazy. I would not be throwing $100 parts around unless you confirm theyre bad.

What did you do to it to mess it up so quickly? Check the oil level. Just dealt with someone that put 3 qts in but forgot to let the original oil out. Sputtered and idled like **** with terrible gas mileage.</TD></TR></TABLE>

i didn't do anything...i bought the car, filled it up and drove normally for a month. i never drove it hard or anything.

 

Any raw gas smell? Check your gaskets and o-rings in and around the fuel rail. Had a problem with mine recently