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Thread: 2009 SRT8 Challenger / supercharged limp mode at highway speed. Need some advice

  1. #1
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    2009 SRT8 Challenger / supercharged limp mode at highway speed. Need some advice

    Im pretty new to this. Im trying to figure out an issue with my KB 2.8L supercharged 6.1 hemi. It has the mammoth 148mm TB which i believe may be causing my issues. After a lot of tuning it finally runs really good but im still having an issue with the car going into "limp mode" and losing my throttle when cruising at a steady rpm down the highway (usually 1800-2200ish rpm). it isnt throwing any codes as i have all those pesky airflow codes disabled, but the traction control light will flash on when i lose the throttle.

    i was FINALLY able to catch it on a log yesterday but i cant see anything obvious, although im very new to this.

    would one of you nice folks be willing to have a quick peek at the log and my tune and see if there's anything obvious? im stumped

    NOTE: the log is extremely long but the event is right at the end where the speed falls to 0.

    thanks in advance!!!!2009 dodge challenger srt8 supercharged - current tune.hptthrottle loss at cruising speed-09SRT.hpl
    2009 - SRT8 Challenger 6 speed - Kenne Bell 2.8LC - 520whp (for now)
    2014 - Ram 1500 Sport
    2013 - Volkswagen Touareg 3.0 TDI

  2. #2
    Tuner in Training
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    You shouldn't have to disable any airflow codes, just fix the tune. You are probably setting DTC for P2173/P2175. Make sure all your Adap tables are adjusted.

  3. #3
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    Quote Originally Posted by allpargarage View Post
    You shouldn't have to disable any airflow codes, just fix the tune. You are probably setting DTC for P2173/P2175. Make sure all your Adap tables are adjusted.
    thanks for the reply.

    my P2173 add adap max is set to 8 g/s
    and P2175 Minimum is -5g/s.

    i have another "assumed" STOCK 6.1 file that shows these same values.

    would setting these to max values potentially fix this? please excuse my lack of knowledge, im really green at this stuff..
    ill probably try enabling sensed MAP as well
    Last edited by boostedhemi; 1 Week Ago at 09:13 PM.
    2009 - SRT8 Challenger 6 speed - Kenne Bell 2.8LC - 520whp (for now)
    2014 - Ram 1500 Sport
    2013 - Volkswagen Touareg 3.0 TDI

  4. #4
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    Looks like it running way lean, LTFT adding 22%- 29% and STFT adding another 8%.

  5. #5
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    I was also noticing the fuel trims seemed excessive but I don?t know enough yet to figured out how to correct it. Had a ?professional? tune the car, and it runs fairly good.. but I?ve spent so much money on dyno tuning by other people that I decided to learn how to deal with this sh** myself 🙄.

    My dyno runs show below 12:1 afr through the entire rpm range. Would that be because the trims are adding so much fuel that it isn?t actually lean? Or could it be total BS

    My wideband is on the fritz right now so I can?t even see where I?m at until a new one comes in

  6. #6
    What do you have for a fuel system? Tell us about the build.

  7. #7
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    Quote Originally Posted by Kmoney View Post
    What do you have for a fuel system? Tell us about the build.
    -stock in tank pump with kenne bell's "boost-a-pump"
    -50lb injectors with the blower kit
    -kenne bell "mammoth" 148mm throttle body

    basically the basic 2.8L liquid cooled blower setup from KB, minus the ridiculously oversized TB
    Im not 100% on the flow rate of the injectors though, i bought the car from a dealer with the blower already on and they couldnt tell me a damn thing
    2009 - SRT8 Challenger 6 speed - Kenne Bell 2.8LC - 520whp (for now)
    2014 - Ram 1500 Sport
    2013 - Volkswagen Touareg 3.0 TDI

  8. #8
    Tuner in Training
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    Adjustments to your VE tables should address the LTFT issue.