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Thread: Jeep tuning master thread

  1. #21
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    well hopefully I didn't just waste $50 on a credit for this, but I am having an issue writing a tune to my Jeep ECM, it gets past the radio warning, ign off, ign on, then when it gets to the point of erasing it says that it aborted, and write failed or something like that.

    according to the vehicle compatibility list the 97-04 wrangler 4.0 is supported by the MPVI3 or at least that is what I am led to believe since there is not a (2) after the vehicle type.

    any ideas?

  2. #22
    Quote Originally Posted by Gordon-0 View Post
    well hopefully I didn't just waste $50 on a credit for this, but I am having an issue writing a tune to my Jeep ECM, it gets past the radio warning, ign off, ign on, then when it gets to the point of erasing it says that it aborted, and write failed or something like that.

    according to the vehicle compatibility list the 97-04 wrangler 4.0 is supported by the MPVI3 or at least that is what I am led to believe since there is not a (2) after the vehicle type.

    any ideas?
    I kind of gave up on my jeep. Just figured my CEL and poor tuning from Chrysler is just a forever thing on these Jeeps. LoL. I get the same message. I was thinking about sending in my mpvi2 to upgrade to the mpvi3, so I might be able to tune my jeep, but it looks like the mpvi3 doesn't work either.

  3. #23
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    it finally worked for me using the beta software to write the tune.
    reading the tune works fine in the regular software.

    question: for timing, there are 3 tables, "main spark (egr off)", "main spark (egr on)", and "warm spark".
    I would assume that warm spark was the table to use, but the values to "enable" it make no sense.

    warmsparkthresholds.png

    looking at the values, warm spark will be used between 8c and 40c, then turn off until 90c ?
    is this right?

    also, while datalogging, is there any way to tell which table the ECU is using?

  4. #24
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    Great thread. I have a supercharged 2005 Jeep Rubicon. I am told and believe its running lean. Just bought a MPVI3 and am starting to do some logging. I have an exhaust leak that I am fixing with a banks header which I am having drilled and welded for a wideband sensor. Not planning on doing any tuning until I get the new header on and have plenty of logging time on it. Just wanted to say hi, and share my experiences here in the journey so it might help others. The jeep runs well, but I am sure there is plenty of room for improvement now that there is a tuner that supports my jeep. On recommendation in another post, I bought the Engine Management Advanced Tuning book by Greg Banish. I was happy to find it had a pretty good section in there on superchargers and turbos. Trying to get up to speed (pun intended) on all this so I am not asking stupid questions.

  5. #25
    Quote Originally Posted by scottie1134 View Post
    I kind of gave up on my jeep. Just figured my CEL and poor tuning from Chrysler is just a forever thing on these Jeeps. LoL. I get the same message. I was thinking about sending in my mpvi2 to upgrade to the mpvi3, so I might be able to tune my jeep, but it looks like the mpvi3 doesn't work either.
    Well, after about a year of not really caring all that much, I finally flashed my jeep with the new MPVI3. It works. Turns out, for me, the MPVI2 was the problem the whole time. Fortunately it's only 1 credit to flash these older modules, so I just assumed I was out $50 or something. And a little bit of frustration. The jeep tuning is absolutely awful. I ended up picking up about 40 ft lbs down low and about 30 hp up top. It's whole different jeep now. Throttle response is actually a thing now. I wish I could do some trans tuning, but the scanner doesn't show output shaft speed. So I don't know if it's worth it to find another logging program to read trans output shaft speed in attempts to make changes there. But I'm pretty stoked about finally being able to enjoy my header and intaker. And no more CEL... so far

  6. #26
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    Hello , I have a supercharged jeep 4.0 , 36lb injectors and a 2.5 bar map sensor. It currently idles at 9.0 afr is there any ways to scale the map sensor for 2.5 or should I just be adjusting my afr in the power enrichment table ?

  7. #27
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    Hi new to tuning. 2005 Wrangler with fully rebuilt 42RLE also. Just got the MPIV3 and changed the 4.0 to a 4.6 which resolved my running rich. Fuel trims are back in line. I seem to have no power when I try to get it to drop a gear going about 55. I'm assuming I need bigger injectors and it looks like 24lb should be good enough. Very mild build sourcing parts from Russ and a comp cams 4x4 cam. I'm trying to find details on what calculations and tables I need to change for injectors. I've haven't even looked at how to change settings for the cam. From what I have gathered these computers don't offer a lot and aren't comparable to tuning an LS. I'm new to tuning, so if someone can point me in the right direction that would be much appreciated.

  8. #28
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    Attaching stock 2005 Wrangler tune here for others.

    2005JeepTJ_factory.hpt

  9. #29
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    Here is what I'm confused about iSnapchat-529241876.jpg

  10. #30
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    2005 Jeep Wrangler 4.6 I6 Stroker (wife's Jeep)
    2004 Jeep Wranger LJ 5.3 LS Swap in progress
    2018 GMC Sierra L5P to be tuned eventually

  11. #31
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    I watched his videos a few days ago. He uses a Honda 1.9 bar map sensor and set is multi to 190 along with map sensor min and max that's what I'm trying to figure out

  12. #32
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    I had two different issues. First was a bad PCM which caused all sorts of weird issues at idle and low speed reversing. Second was a bad fan clutch causing it to overheat. I'm all figured out until we order some bigger injectors, as it at times seems to need to add fuel, But it's mostly 0/-1/-2 of short term trims.
    2005 Jeep Wrangler 4.6 I6 Stroker (wife's Jeep)
    2004 Jeep Wranger LJ 5.3 LS Swap in progress
    2018 GMC Sierra L5P to be tuned eventually

  13. #33
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    2000 Jeep Cherokee Sport 4.0 (California Emmisions) Stock Tune

    Uploading this to the record
    Attached Files Attached Files

  14. #34
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    so I realize that it will be hard to say without a wideband setup, but this log was taken after a recent LTFT reset. It's showing quite a bit of fuel being pulled all over the map.
    what would you all recommend I start by doing?
    this is a 2002 Jeep Wrangler with a 4.0, cut down intake tube and cone filter, reworked exhaust with stock-ish muffler, and a slightly larger than stock cam (don't remember the number it was quite a while ago when I put it in).

    jeepLTFT.png

    hopefully I did it correctly, I think I uploaded the tune and log. the tune is mostly stock I've disabled DFCO to try and help with some super-extreme engine braking and "bucking" when going between engine braking and light throttle.
    Attached Files Attached Files

  15. #35
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    I did end up using the LTFT data from the tune to cut back the fueling by half of whatever the LTFT data showed. This greatly improved the "off idle" drivability. I'm still seeing a lot of "bounce" in the timing at idle. I don't have enough about tuning to know if this is normal. Can someone take a look? It's basically rhythmically bouncing constantly and you can hear it in the idle.

    uploaded a short log and the current tune
    Attached Files Attached Files

  16. #36
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    I think the timing jump has something to do with idle speed and smoothing. Could the bigger cam be causing the computer to react that way?

  17. #37
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    installed a knock sensor and Wideband in my 97 Jeep ZJ 4.0. Planning to do some road tuning this weekend.

  18. #38
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    FYI, as the OP said in posts. You have to force open loop for any adjustments to your fuel table to actually take affect. This can be changed Fuel > Oxygen Sensors > closed loop enable box > set to a high temp like 300 F and you should set your "closed loop disable" High RPM hi to a low rpm like 512 rpm. Once this is all set your O2 sensor will no longer be used to error correct your mixture to stoich and will be running off the base fuel map.

    Base fuel map for me has been lightly adjusted for a manual jeep but I found it to run real rich from 0.95 lambda to 0.81 in a lot of areas. the power difference is definitely there. As there are a few compensation tables I would data log as much as possible and see where you need adjustment whether its base fuel map or something like Power Enrichment. You could also zero out the entirety of power enrichment and be more focused on the base fuel map.

    I have a knock sensor for a jeep 4.0 installed and being detected by VCM scanner So once AFR is adjusted to my liking then its off for some advance timing adjustment. Will try to give updates

  19. #39
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    Quote Originally Posted by Gordon-0 View Post
    so I realize that it will be hard to say without a wideband setup, but this log was taken after a recent LTFT reset. It's showing quite a bit of fuel being pulled all over the map.
    How are you resetting the LTFT's? I would normally check the VCM and Special Functions, but I don't get anything when I hit the button. No options at all.

  20. #40
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    Quote Originally Posted by ALVAREZ1112 View Post
    How are you resetting the LTFT's? I would normally check the VCM and Special Functions, but I don't get anything when I hit the button. No options at all.
    LTFT is reset by disconnecting the batterys negative and letting it sit 10+ mins or over night. LTFT will only adjust to be at stoich. If you reset your LTFT then at startup it will dump fuel until it can get inself dialed into stoich by reading the O2 sensors.