1. Welcome to Jeeps.net!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Jeep discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Jeep owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

1999 jeep runs horrible coming up to heat

Discussion in 'Wrangler TJ (1996-2006)' started by steve7962, Sep 28, 2018.

  1. Sep 28, 2018 at 9:32 AM
    #1
    steve7962

    steve7962 [OP] New Member

    Joined:
    Sep 28, 2018
    Member:
    #2612
    Messages:
    2
    Gender:
    Male
    First Name:
    steve
    Vehicle:
    1999 wrangler sahara
    none
    my jeep starts great and runs smooth until it gets above 125 and having a load on it. it rins horribly until it hits 180 and rides vreat. have replaced temp sensor and upper O2 sensor. did absolutely nothing. any ideas?
     
  2. Sep 28, 2018 at 9:45 AM
    #2
    Prerunner1982

    Prerunner1982 Well-Known Member

    Joined:
    Aug 4, 2017
    Member:
    #1745
    Messages:
    1,356
    Gender:
    Male
    First Name:
    Jon
    Vehicle:
    93 XJ 2 door
    Welcome Steve. That is an interesting problem. I would have definitely suggested the temp sensor so good call there but other than that I am not sure where to point you next.
    If it didn't get better I could see a number of sensors causing the problem but the fact that it gets better above 180° would almost definitely point towards a temp reading.
    Perhaps someone else here has a better idea.
    If you are able to resolve the issue please come back and let us know.
     
  3. Sep 28, 2018 at 10:55 AM
    #3
    Awrench

    Awrench Well-Known Member

    Joined:
    May 12, 2018
    Member:
    #2303
    Messages:
    975
    Gender:
    Male
    Vehicle:
    3 jeeps
    a 1999 GREAT - NO ISSUE BEFORE REACHING TEMP?
    starts quick, not feathering throttle st start?

    I would suggest you use a scanner and retrieve ALL codes.
    O2 sensor is new - only use jeep or NTK brands.

    If you have a scanner - check ECT - o2 voltges - Fuel Trims- And MAP.
     
  4. Sep 28, 2018 at 2:14 PM
    #4
    steve7962

    steve7962 [OP] New Member

    Joined:
    Sep 28, 2018
    Member:
    #2612
    Messages:
    2
    Gender:
    Male
    First Name:
    steve
    Vehicle:
    1999 wrangler sahara
    none
    the engine throws no codes what so ever. it has been to two of the best mechanics in town. they are starting to think a brain problem
     
  5. Sep 28, 2018 at 8:53 PM
    #5
    aggrex

    aggrex Well-Known Member

    Joined:
    Sep 12, 2016
    Member:
    #203
    Messages:
    4,832
    DE
    Vehicle:
    Backcountry '16
    Tuffy>AEV>TTO>JW>STech>EVOcage>MagnaFlow>SpiderTrax>RockHard>TF>SpringTail>67design>Bolt>GPCA>Curt>
    Welcome! Bit unusual to run only well at 125 then 180 but not in between those temps. Are those temp readings with a reliable gauge? Performed routine coolant or thermostat maintenance?
     
  6. Sep 29, 2018 at 1:47 PM
    #6
    Awrench

    Awrench Well-Known Member

    Joined:
    May 12, 2018
    Member:
    #2303
    Messages:
    975
    Gender:
    Male
    Vehicle:
    3 jeeps
    interesting, I have A different read on the issue.

    I read it is ok warming up @ 125 but only goes to shit a 180Deg and up?

    You have NOT changes the thermostat?
    You are NOT consuming coolant?
    NO modifications ? talking powertrain.

    I would suggest a scanner Ck codes* and look at live data... check ECT before first start compare to ambient how far off are they? Look at fuel trims at start and at the temp that issue starts...observe o2 sensor voltages and MAP.


    * a SCANNER IS NEEDED to retrive ALL codes - key on off and code readers are lacking.
     
To Top