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opinion

Discussion in 'Early CJ5 and CJ6 Tech' started by 52m38, Jan 15, 2009.

  1. Jan 15, 2009
    52m38

    52m38 Same jeep since 1980

    Cody WY
    Joined:
    Jul 29, 2008
    Messages:
    96
    ok guys thinking caps on.
    so i posted today about my shockingly poor mileage.
    I had a thought (1 a month limit)
    My speedo cable is bad,,it binds a bit which causes my speedo to not only bounce like mad but to some time read way to fast. like sometimes 20 mph to fast.
    except if my speedo is fast it gives me more miles which would make my mileage better.

    can a motor(225-420-3.73's) that runs great and is not rich only get 8 mpg
     
    52m38, Jan 15, 2009
    #1
  2. Jan 15, 2009
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
    Joined:
    May 18, 2006
    Messages:
    2,622
    I think it would be tough in a 225. Mine was terribly rich when I got it and only down around 11mpg
    Posted via Mobile Device
     
    jayhawkclint, Jan 15, 2009
    #2
  3. Jan 16, 2009
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
    Messages:
    8,360
    If your speedo is reading that high at times, I'd bet it's the speedo, not the cable....FWIW.
     
    Patrick, Jan 16, 2009
    #3
  4. Jan 16, 2009
    farfle

    farfle old dog

    Mariposa, CA
    Joined:
    May 14, 2007
    Messages:
    430
    The speedometer needle is driven by magnetism, there is no direct connection to the cable. The odometer part of the speedometer is gear driven. Therefore, your speedo mph reading can be goofy, but your mileage reading will remain proper, given gearing and tire size changes. There are quite a few posts here on the forum if you take the time to search that will explain how the speedometer works. I'll bet the speedometer cable doesn't have much if anything to do with your mileage problem.

    When I retrieved the 75, bought new by his mom from her son who had it for a few years, the thing got 5mpg :shock: on the trip from Santa Barbara to Mariposa. (It is a 258, but the 6 and the 8 get similar mileage.)

    Her son had not really modded the jeep, the low mileage was a result of what I will politely call "deferred maintenance". Took a while to find all the vacuum leaks, misadjusted carb, poor wiring, restricted air cleaner (heat diverter flap rusted shut) and plugged PCV system. Just an accumulation of deterioration.

    After working my way through the various systems, I'm getting an average honest 15-16mpg, and I live in the mountains.

    I guess I just trying to say that to solve your mileage problem, start with the basics. Compression check, etc, etc. Gives you a basis to go on.
     
    farfle, Jan 16, 2009
    #4
  5. Jan 16, 2009
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
    Joined:
    Mar 29, 2007
    Messages:
    5,929
    You may have some rotted fuel lines that are spewing fuel as you go down the road and or plugged exhaust system (or restricted) causing high fuel consumption.
     
    Walt Couch, Jan 16, 2009
    #5
  6. Jan 17, 2009
    52m38

    52m38 Same jeep since 1980

    Cody WY
    Joined:
    Jul 29, 2008
    Messages:
    96
    new headers new fuel lines.no smoke runs great,, maybe it will get better.
    guess i need to take it a know distance and compare to odometer
     
    52m38, Jan 17, 2009
    #6
  7. Jan 17, 2009
    sdcj6

    sdcj6 Sponsor

    San Diego
    Joined:
    Sep 25, 2002
    Messages:
    366
    Use a GPS for measuring your mileage. If you don't have one, someone you know does. Borrow his.
     
    sdcj6, Jan 17, 2009
    #7
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