my car is eating gas

Posted by 99Mitsu, Dec 25, 2009
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  1. 99Mitsu

    99Mitsu Proven Member

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    OK, I last month I replaced my o2 sensor (the one by the turbo). My car was getting about 22mpg highway and 18 city. In the last week my car has been going through gas like water. I now go about 75 miles city and my gauge is at half. I dont see or smell anything wierd in my engine so i dont think its a gas leak.

    Now I have an exhaust with no catalytic, I dont know it the o2 sensor could throw off my mixture if I have no cat.

    please help
    Merry Eclipsemas ~ Mitsu
    #1
  2. pj91gsx

    pj91gsx Freelancer

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    Stuart, Virginia
    boost leak test.
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  3. boostd_mitsu

    boostd_mitsu Proven Member

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    hook it up to a scanner and see what the ect (engine coolant temp) is. if your temp sensor is bad they will read -44 and that will use alot of gas cause the computer thinks it that cold and is running very rich to warm up the motor faster. it won't always set a cel either so just check.
    #3
  4. dsmtun3r98gst

    dsmtun3r98gst Proven Member

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    so your getting about 150 to a full tank??? well your going to find out that alot of dsmers are getting about 15-17 mpgs so its not like if your going to be a minority when it comes to that..... but like pj91gsx said: do a boost leak test.

    Do you have a CEL?
    #4
  5. Boost_Addict_88

    Boost_Addict_88 Proven Member

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    When was the last time you changed your plugs and wires? I had a similar gas mileage issue earlier this year. Turned out my plugs were sh!t (not to mention 3 Champions and a Boush). I had gotten the car about 5 months prior and hadn't had a chance to (nor did I pay it any mind for some reason) to change them. Needless to say, I was furious and I walked to Kragen for a new set of NGKs. Point is, after I changed them, I got better fuel economy. Also, check your fuel filter, air filter, and fill up with Shell (if you don't already). I've noticed very nice results when I use Shell gas vs others, but that's just my opinion.
    #5
  6. rEclipserGST

    rEclipserGST Proven Member

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    G-gity, Ohio
    Did you reset the ecu after the install of the o2 sensor?
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  7. 99Mitsu

    99Mitsu Proven Member

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    Chiacgo, Illinois
    @boostd mitsu; what kind of scanner do i need? would an OBDII scanner show engine temp?

    @dsmtun3er; dont know what a CEL is and what do i need for a boost leak test

    @boost addict; im running NGK plugs and wires, put them in back in july

    @eclipserGST; since I dont have EMPROM i dont know how to reset my ECU
    #7
  8. boostd_mitsu

    boostd_mitsu Proven Member

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    Eau Claire, Wisconsin
    an OBD2 scanner should show you live data, a CEL in a check engine light, and to reset the ecu all you have to do is disconnect to battery for like a minute or two. do you have a hard start condition?
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  9. dsmtun3r98gst

    dsmtun3r98gst Proven Member

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    CEL= check engine light. and umm for a boost leak test you need a boost leak tester LOL. you could either buy one or make one yourself. if you serch enough you can find one real easy. its a vacuum leak tester, they even sell em like at Autozone
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  10. dSmgs-T

    dSmgs-T Proven Member

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    A CEL is a check engine light.

    i would do plugs, wires, fuel filter, maybe clean the injectors and definitely do a boost leak test.
    #10
  11. dsmtun3r98gst

    dsmtun3r98gst Proven Member

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    Not all OBD@ scanners have that capability.... you have to get the really expensive ones. maybe a few cheaps ones may have it as well not quite sure
    #11
  12. oneslowwdsm

    oneslowwdsm Proven Member

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    I don't think that would cause less than 20mpg.


    What kind of mods are you running? Stock fuel pump and such? My car is bone stock and I get 30mpg freeway and around 24-25 city.
    #12
  13. rEclipserGST

    rEclipserGST Proven Member

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    G-gity, Ohio
    Wow you must have a super car WTF
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  14. oneslowwdsm

    oneslowwdsm Proven Member

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    No?

    http://i136.photobucket.com/albums/q166/romodavid15/IMAG0081-1.jpg

    Proofz :D
    #14

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