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Thread: No throttle but still runs up and shifts gears

  1. #1

    No throttle but still runs up and shifts gears

    Hello All,
    I'm new to the tuning world so this may be a stupid question. I am helping a friend on a jaguar with a 5.3 with a LS2 cam and a Professional Products aluminum intake. The car has a "mail order" so to speak tune. Car starts fine and idles fine in park and drive. In fact it even runs decent. But the problem I am having is when you put the car in gear. You really have to hold the brake. If you let off the brake you do not have to touch the throttle. the car will run up to speed and about 16-1700 rpms and shift into 2nd gear. Is there anywhere in the tune I should be looking? Is this a tune issue or a torque converter issue. I'm pretty sure the converter is stock and came with the 4L60???. Any help would be greatly appreciated.

  2. #2
    Tuning Addict 5FDP's Avatar
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    Post the tune file and logs.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    this is the original tune when I got it.
    Last edited by Custompowr; 01-21-2017 at 10:19 PM.

  4. #4
    Tuning Addict 5FDP's Avatar
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    Just from comparing with a similar stock tune file, the base running airflow in gear was just widly added too in my eyes. I don't think it needs to be that high. For whatever reason this mail order tune made both the in park/neutral and in gear BRAF tables the exact same.

    That cam isn't very big, I'd return those to stock and see how it runs.

    I'd even return the MAF curve and VE table back to stock, seems that it was just added too as a guess. You'd have to retune them regardless so starting off stock seems easier.

    Without a log I can't see how it running.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  5. #5
    sorry I was wrong. the cam is a 219/228 @ .050 on 112LSA and .525 .525 lift.

  6. #6
    I tried uploading a log. If it didn't work please let me know. Its the first time I've uploaded anything in this forum.

  7. #7
    Thank you for the info. I will look into making some changes there.

  8. #8
    Will the BRAF in gear keep it idling fine in park/gear? The actual idling is fine in both park and gear while holding the brake. The problem is only when taking foot off the brake. Acts like converter stays locked or not enough stall. Once again thank you for your patience and wisdom!

  9. #9
    Tuning Addict 5FDP's Avatar
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    My first thought was that the cam was much smaller, so my guess could be a little off now. I mean you can always try and adjust it a little bit.

    I notice too that they change the spark timing at idle and in gear, could be tied together there.

    This is running all the electronic stuff for the throttle and pedal right? Because 2004 was drive by wire.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  10. #10
    Yes this is electtric throttle.

  11. #11
    This is a log I just took sitting in my driveway. The TPS changes just idling in park and from park to drive without ever touching the throttle. Is that correct?

  12. #12
    I also changed the BRAF for in gear and the idle spark advance in gear. Didn't seem to make any diff. Maybe I didn't do it right?

  13. #13
    Any ideas?

  14. #14
    Senior Tuner Russ K's Avatar
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    Use this Idle Aiflow layout & do a cold start scan in park till operating temp, don't touch the throttle while scanning.
    Then do the same in gear. Then just copy & paste the Idle Desired Airflow histogram into the BRAF table in the editor.
    Make sure that your units (metric or imperial) match in the scanner & editor. And for the colder temp cells that you missed, just make them the same difference from stock as the next closest cell that was scanned.

    And a stock torque convertor is too tight for that camshaft, a 4.2L trailblazer convertor would help a lot.

    Russ Kemp
    Attached Files Attached Files

  15. #15
    Thank you Mr. Kemp for the Layout! I really appreciate your help! I will try it tomorrow as I have already been running it tonight. Thanks again!