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Thread: 99 Jeep XJ

  1. #21
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    Quote Originally Posted by 2001CamaroGuy View Post
    Unfortunately, the jtec+ stuff is currently really flaky and not a mature system yet (I've been using HPTuners on GM stuff since it came out in 2003).

    - I've got two XJ Cherokees (a 2000 and a 2001). I can write to one (the 2001) but not the (2000).
    - The scanner doesn't work on either of them.
    - They have started unlocking DTCs, but when a DTC is changed, the change doesn't stick.

    I'm not complaining, just stating facts. I hope things will continue to improve over the next 6 months.
    Yeah I noticed the DTC thing on my '96. I want to run a '97 PCM, but I need to disable the CCD bus DTC to get rid of the check engine light.

  2. #22
    I get the same P0700 on my 01 XJ. Goes away after a few ign. cycles so I'm not too concerned. Logging seems a bit better now too!

    Still trying to make sense of how the actual tuning process should go but I'll keep tinkering with it.

    So far I rescaled my spark and fuel maps to 80kpa to try to get some more resolution out of those tiny tables lol. I'm in Colorado and maybe see 81kpa on a good day.

    Working on stft + ltft against the fuel table but seems like it's a bit finicky. Maybe the fuel adder tables have to be 0'd out first? Like Accel enrichment or part throttle PE them added back in and tuned separately?
    It would be nice to have commanded fuel PID to be able to filter on the scanner.

    Not my intention to hijack, just want to get some more info out if I can and get our wheels turning.

  3. #23
    Advanced Tuner IARLLC's Avatar
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    Quote Originally Posted by 2001CamaroGuy View Post
    Unfortunately, the jtec+ stuff is currently really flaky and not a mature system yet (I've been using HPTuners on GM stuff since it came out in 2003).

    - I've got two XJ Cherokees (a 2000 and a 2001). I can write to one (the 2001) but not the (2000).
    - The scanner doesn't work on either of them.
    - They have started unlocking DTCs, but when a DTC is changed, the change doesn't stick.

    I'm not complaining, just stating facts. I hope things will continue to improve over the next 6 months.
    Same here. I hope that they put some more time into these.
    It would be nice to be able to dump rear O2s, scan, and refine these 4.0s.

  4. #24
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    Hi interested to know how you got on with the xj turbo and what changes were needed

    any map sensor scaling changes ?
    could a 3 bar sensor be wired in ? and scaled accordingly ?

    feel free to post a base map if possible, not interested in your final map as mods and such will differ but just keen to understand what changes were made to accomodate boost in the xj map
    thanks

  5. #25
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    Nice, thanks for the knowledge.

  6. #26
    OK, so....

    I am in need to convert my setup from AEM F/IC 8 to reflashed Jeep PCM as my D/FI has died and they are no longer made. What fun. My setup is a Sprintex Supercharger using 36 pound Accel Injectors. The system makes 8.5 PSI boost up here a 6,000+ feet altitude. Has anyone been successful in getting a boosted application to behave itself? As of now, the XJ is a rather large Lawn Jockey. Looking for some feedback prior to making yet another attempt to get the stock PCM mind it's manners under boost.

  7. #27
    Advanced Tuner sarg's Avatar
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    Pretty exciting to see tuning in some form is capable with the XJ. I am looking at them now and was wishing I could tune them, haha.

  8. #28
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    Reviving this from the dead. Are only select Jtec pcms able to turn off rear o2's?

  9. #29
    Advanced Tuner sarg's Avatar
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    I actually ended up getting a 99 XJ. I look forward to folks sharing some of their experiences. So far it looks very limited compared to the LS stuff I am used to tuning. Very few tables.

  10. #30
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    Going to hop on the bandwagon of this thread with my wife's '98 XJ with a 4.7 stroker in need of some tuning love. I have another thread here that I'm try to troubleshoot through the lack of options in the tune file for both engine and transmission tuning. https://forum.hptuners.com/showthrea...-missing-a-lot

    Anyone able to tune the AW4 for starters using HPT?

    How do you folks actually dial in the fueling and airflow needs of a modified engine? I'm familiar with the LS-side of the house, but this is a new ballgame it seems.

  11. #31
    Quote Originally Posted by 2001CamaroGuy View Post
    Unfortunately, the jtec+ stuff is currently really flaky and not a mature system yet (I've been using HPTuners on GM stuff since it came out in 2003).

    - I've got two XJ Cherokees (a 2000 and a 2001). I can write to one (the 2001) but not the (2000).
    - The scanner doesn't work on either of them.
    - They have started unlocking DTCs, but when a DTC is changed, the change doesn't stick.

    I'm not complaining, just stating facts. I hope things will continue to improve over the next 6 months.
    I agree with what you said. the scanner is not good.

  12. #32
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    No joy on being able to do anything with the AW4 trans controller. It's separate controller ans no one seems to have figured out a way to access it. It sucks. The only option is to use a universal trans controller... but they cost close to $1K.

    Tuning is really simple for the JTEC. If you were weened on modern era GM stuff, just forget everything you've ever learned and go back in time to see how early Ford EEC-IV's were tuned in the 1980's.

    As far as rear O2 sensors, MIL light can be disabled, but you still need to leave the sensor connected. If you unplug the rear sensor, it'll throw a code for the rear O2 sensor heater. And for some inexplicable reason, that P code doesn't show up on the list and therefore can't be disabled.

  13. #33
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    Quote Originally Posted by grimmechanic View Post
    No joy on being able to do anything with the AW4 trans controller. It's separate controller ans no one seems to have figured out a way to access it. It sucks. The only option is to use a universal trans controller... but they cost close to $1K.

    Tuning is really simple for the JTEC. If you were weened on modern era GM stuff, just forget everything you've ever learned and go back in time to see how early Ford EEC-IV's were tuned in the 1980's.

    As far as rear O2 sensors, MIL light can be disabled, but you still need to leave the sensor connected. If you unplug the rear sensor, it'll throw a code for the rear O2 sensor heater. And for some inexplicable reason, that P code doesn't show up on the list and therefore can't be disabled.

    Came across this thread doing some pre-tune research to see if disabling the rear o2's would nix the related codes as well since none are in the dtc list.

    As far as the heater code, the tab next to the dtc's has a drop down box.

    Jeep HP o2 heaters.PNG