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Thread: Why wont this file pull timing when knocking.

  1. #1

    Why wont this file pull timing when knocking.

    Was asked to have a look at this car of a friends, when going WOT the car will knock badly above about 5000rpm, been like that since he bought it, it has some light exhaust and intake mods but nothing major. After a couple of quick runs I was able to get the fueling close which also brought the timing into the correct cell and the knock was gone but the only thing I cant figure out is why I didn't log a single degree of knock retard when the car was so obviously knocking.
    I been through everything I can think off several times and everything in the tune looks like it should be seeing, and pulling timing for knock, I must be overlooking something.

    Can anyone see what I am missing to make the knock sensors work? or could it be a mechanical problem like faulty knock sensors?

    The only thing that looks strange is the values in the "Knock Fast Attack Rate vs. RPM" are way higher than the should be but it appears to me as though HP tuners is displaying the decimal in the wrong spot as I have 19s where I should have 1.9s, 44 where it should be 4.4 but regardless this should just make the knock retard super aggressive.

    In the log you can see a WOT pull at 1.32 where I could definately hear knock above 5000rpm but none was reported in the log.

    Can't tell if the tune has been modded before as I can't find a matching stock file in HPT format.
    Attached Files Attached Files
    Last edited by Xjas; 11-24-2014 at 05:52 AM.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  2. #2
    That cal is a standard 01 VU Ute cal from best I can tell. All I can value add is knock sensors as a general rule on those are unreliable as best. I've seem them do what you've described many times as well as detecting knock that doesn't exist. That said, being a few years old now, there's every chance that they may be faulty as they were prone to corrosion on the early models.

  3. #3
    Tuner in Training
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    I have found the same thing, the knock sensors just suck at picking up high rpm knock. I don't have much faith in them. They seem to work ok at lower rpm. What I don't get is how the early US LS1s ran 28 degrees timing at high rpm without going pop.

    I have noticed weirdness in the knock attack settings too, I think you're right about the decimal place being wrong.

    BTW the MAF on that car looks bad, reading too low, I'd replace it or just tune it mafless (sounds like you've got that sorted already though). Those early Holden spark maps are pretty doughy especially down low, may as well pop in a VZ LS1 spark map while you're in there.

  4. #4
    Quote Originally Posted by SSUte01 View Post
    That cal is a standard 01 VU Ute cal from best I can tell. All I can value add is knock sensors as a general rule on those are unreliable as best. I've seem them do what you've described many times as well as detecting knock that doesn't exist. That said, being a few years old now, there's every chance that they may be faulty as they were prone to corrosion on the early models.
    Thanks, I wasn't sure if it was stock or not, the guy hasn't owned it since new. I might tell him to replace the sensors and we'll see how it goes then.

    Quote Originally Posted by johnm545 View Post
    I have found the same thing, the knock sensors just suck at picking up high rpm knock. I don't have much faith in them. They seem to work ok at lower rpm. What I don't get is how the early US LS1s ran 28 degrees timing at high rpm without going pop.

    I have noticed weirdness in the knock attack settings too, I think you're right about the decimal place being wrong.

    BTW the MAF on that car looks bad, reading too low, I'd replace it or just tune it mafless (sounds like you've got that sorted already though). Those early Holden spark maps are pretty doughy especially down low, may as well pop in a VZ LS1 spark map while you're in there.
    You're spot on with the MAF, not failed though, it is one of those SS inductions larger bore ones which was causing to it to read low.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  5. #5
    Potential Tuner
    Join Date
    Aug 2014
    Location
    Western Australia
    Posts
    9
    I compared your tune file to a stock 2003 Monaro LS1 file paying particular attention to the Engine>Spark Advance>Retard tab.

    This shows the comparison between the files - Compare Xjas Tune to Stock 2003 LS1.jpg

    The green cells / tables have been modified.

    The most drastic and unrealistic values in your tune are in - Xjas Knock Attack Rate.jpg

    Versus the Stock Monaro's - Stock Knock Attack.jpg

    Remember also, these values are further multiplied by temperature and baro pressure variables. ie You may be trying to pull out more than 44 degrees per knock detected.

    Because 44 degrees is not realistic per knock, the PCM may ignore the erronous values in the table and do nothing.

    Comparing the "Knock Sensors" tab also shows many more modifications the most important of which in your case might be the "Knock Sensor Global Gain" table ie. Knock sensor sensitivity

    Find it here Knock Tab.jpg


    I would start by setting All the green Retard tab values back to stock and see what happens.

    I believe the stock settings will get the knock retard working again.

    If it does not, it is still possible whoever made the changes may have failed to diagnose faulty knock sensors and made these drastic edits to compensate. The stock settings will be a healthier starting point if you need to spend $$ on replacing them.

    It would be unusual for both knock sensons to fail completely (not registering a knock under any condition) but it is possible.

    If these stock settings get the Retard working again as expected, you can start playing with the tune from there.

    I hope this helps solve your problem.
    Last edited by Dogsgogrr; 12-01-2014 at 09:11 AM. Reason: swap images around to correct spot

  6. #6
    Thanks for the reply Dogsgorr but you cant just compare the file to any LS1 file and expect them to be exactly the same, there is always small changes from year to year and model to model so the tables wont be the same. As per my first post I belive the Knock Fast Attack Rate vs. RPM is way off due to a decimal display isssue with HP tuners but I'm yet to verify this.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  7. #7
    Potential Tuner
    Join Date
    Aug 2014
    Location
    Western Australia
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    Sorry !! My mistake..... Nowhere in your posts did you state year/model/type so please, pardon my error in randomly choosing a 2003 Manual Holden Monaro Tune file as an example. Shock, horror hehe!

    I will leave it up to you and you alone to identify and locate the relevant factory tune for your mate's model/year of car and then make a comparison to the relevant stock tune.

    But yes you can compare the tunes because by definition Compare = finding the differences, small or large and identifying effects, why etc.

    They are same LS1 base design motors, very similar or identical technology from year to year with varying changes to cam, heads etc along the way, mainly due to emission laws and individual vehicle performance/use requirements hence their popularity.

    Oh yeah, you said "... small changes from year to year ..." so you actually agreed that they are in fact comparable. I did not say they would necessarilly be identical.

    Same identical PCM hardware, same firmware (the program which controls it all using data you enter in tables and data fields) unless you upgrade it to RTT in which case it still controls your motor identically but with the Real Time Tuning enhancement, same box, same plugs to PCM, similar looms etc.

    If you have some time, do a few compares of Factory OEM LS1 Tunes from one year/model to the next like I have and you will generally find minor changes only to suit various cams, upgrades to better but similar sensors etc.

    Ummm, and all the rest of us HP-Tuners don't appear to have the " .... RPM is way off due to a decimal display isssue with HP tuners... " issue.

    That sounds a little like 'shooting the messenger' which, when you think about it, is exactly what HP Tuners software is. It sends you data from your engine and you send back data to modify the tune as a result of the message.

    So why not give my suggestion a shot by setting knock sensor sensitivity to factory defaults for whatever year/model your friend's car is etc? If it doesn't at least part fix your problem then what have you lost? You may even have identified the knock sensors or wiring as the real fault.

    My 54 years have at least taught me I can learn a lot from careful trial and error.

    You can always flash back to the faulty tune yeh?

    Wish you luck!