Page 1 of 2 12 LastLast
Results 1 to 20 of 22

Thread: Jtech Fueling issues

  1. #1
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20

    Question Jtech Fueling issues

    Ive been running a jeep xj built 4.7 stroker for around 1 year now, Its been on Hp since October. Finally desired to correct the fuel trims by locking out closed loop, pulled the O2 and disabled. Reset pcm. Started her up and shes running at 12.80 idle, so I start pulling fuel out via EGR off map..... No mapped how much I pull out shes still sitting at 12.8, min injector pulse has also been lowered, seems she cant go under 5.0 ms no matter what i do, normally closed loop shes at 2.0-2.5ms tops. Am i missing a step here?

  2. #2
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    813
    fuel>general>min pulsewidth ?

  3. #3
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    Min pulse has been changed, currently at 1180 from 1600; zero chance shown at idle.

  4. #4
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    813
    Post your file.
    If in doubt, multiply everything by 1.1.

  5. #5
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    Quote Originally Posted by spoolboy View Post
    Post your file.
    here it is, thanks for the help

    jeephotfilefuelingissue.hpt

  6. #6
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    813
    Is it getting out of the cold/warmup maps?
    If in doubt, multiply everything by 1.1.

  7. #7
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    Yes she’s reaching full temp and out of the 120 sec warm up window.

  8. #8
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    813
    Did you try resetting all adaptives?

    Lastly, are your coolant temp and map sensor reading correctly? Did you happen to change to a 2 bar sensor or something?

    If it's none of that, I am also stumped.
    If in doubt, multiply everything by 1.1.

  9. #9
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    I’ve got a redundant coolant temp sensor, they read within 5 degrees of each other, still a oem mopar sensor; and I’ve reset adaptives with scan tool and by pulling battery. That’s also what I was thinking, like the dme is saving adaptations somehow.

  10. #10
    Tuner
    Join Date
    Jan 2020
    Location
    Yuma ,AZ
    Posts
    103
    unless you have different injectors and know what you are doing, leave min pulsewidth alone. try removing positive cable and touch to negative for around 10 seconds, that has been working for me on jtec ecm's, i tested this procedure many times and it seems to make a difference

  11. #11
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    They are 29# injectors, stock was 21#. I’m going to try touching the cables tonight.

  12. #12
    Tuner
    Join Date
    Jan 2020
    Location
    Yuma ,AZ
    Posts
    103
    you know what they came out ?

  13. #13
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    813
    What do your fuel trims show in scanner?
    If in doubt, multiply everything by 1.1.

  14. #14
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    They are new to the motor accel injectors, motors been running for a year with them now. Fuel trims are reading zero, before I locked out closed loop they were at 8%, which I initially took out 10% fuel to make up for it.

  15. #15
    Tuner
    Join Date
    Jan 2020
    Location
    Yuma ,AZ
    Posts
    103
    what mods on the engine, post a scanner file too

  16. #16
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    I don’t have a current log file; she’s fully built, 9.8:1, scat crank, roller cam, head studs, ported & polish; anything you can do to a 4.0. Zero short cuts... I build Porsche race cars for a living; you’d think a Jeep would be pretty simple lmao.

  17. #17
    Tuner
    Join Date
    May 2005
    Location
    Los Angeles
    Posts
    161
    The pulse width should directly translate to what you put in the map. Basically under normal (idle and light throttle) conditions injector pulse-width = fuel table + battery offset + injector offset. Have you datalogged the injector pulse width before and after your change ? If so is it changing ? If so maybe you need to try a new wideband sensor. If not then very possibly you either are making changes to the area of the map that the engine is not actually running or making changes to the wrong fuel table. Have you tried copy-> pasting the EGR off map to the EGR on map?

  18. #18
    Tuner
    Join Date
    Jan 2020
    Location
    Yuma ,AZ
    Posts
    103
    i look at your file,you need to take fuel out, it looks like you added fuel to some of the idle and cruise portion of the fuel map. if you have 29# injectors you need to take out similar fuel from all the fuel map

  19. #19
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    It’s only to rich at idle, normal mid throttle isn’t to lean, 15:1 at times. I’m not worried about that currently, and it’s a 130 more hp then stock, it needs more fuel off idle.

  20. #20
    Tuner in Training
    Join Date
    Oct 2019
    Posts
    20
    And that fuel map I sent is 100% stock fueling other then 15 kpa section, that’s only a text map