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Thread: Injector Duty Cycle & PIDS Frustrations!!

  1. #1
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    Exclamation Injector Duty Cycle & PIDS Frustrations!!

    Granted, I have the unique task of having two unique hybrid monsters a Gen IV 5.3L w/6L80 and Ls2 w/6L90 to optimally "tune", so I am venturing into territory that few if any outside GM have gone.

    Nonetheless, after months of reading through threads, reaching out to members like JoeCar, and just plain burning up a lot of hours and gas messing around EFILive, I finally took felt confident to set up my own some semi-logical dashboards and maps to gather the data I felt was most necessary to help me get these 6L80/90 twins running strong. I got a good collection of PIDS that still allow decent frame rate logging. Even got a decent log from a WOT track run really helped pull things together and allowed me to change quite a few calibrations. But alas...I notice something bizarre in my logs. My injector duty cycles were idling at 170%+!!!!!! WTH???

    So I think...oh crap...I changed too many parameters at once. I could have sworn those were 'safe' and/or 'moderate' changes. Crap...now I have to go back and see what might be off. Well...I spent...correction "wasted" my Saturday attempting to tweak my Trailblazers....jumping from one truck to another... burning out my starter...wreaking havoc on my ECMs and TCMs. Finally I put the stock tune back in. Now it runs even worse...WTF?? And the lowest Duty Cycle I'm getting is 106%. Is my pump bad? Maybe my pump calibrations are off??



    A lot of cussing, a lot of rum, more cussing, a lot of bad mojo to friends and family, more rum...a thought occurred to me based on a thread I read. Maybe it's not your injector calibrations...or your MAF settings...or your PE mod...maybe it's your pids.

    Well to make a long story short...yeah I know, too late ...a word of caution to the NEW-to-EFILive calibrators/tuners.

    A) Be careful with you EFILive USB plug. With less year of use on my own vehicles mine has gotten to the point of becoming sensitive right behind the square USB plug so that it will lose connection with the slightest touch. No cuts. No visible damage to the insulation. Not cool when trying to data log on a drive. You'll want to wrap a good inch or 2 of the protuding wire with self vulcanizing tape to add resistance to its kinking. I personally would like to see 90 degree USB cords.

    B) Not sure if it's mentioned in tutorials or anywhere else, but it's best to close out your TUNE FILE before opening up the SCAN LOG. Maybe even unplug the Data Link Connector (DLC). I discovered that EFILive would apparently get hung up in the Pass Thru and freak out the ECM. When I kept both SCAN and TUNE open I'd get everything from hanging idle, sluggish revving and shift hang ups.

    C) Among other PIDS, I'm sure, do NOT, repeat...do NOT have Intake Valve Temp PIDS selected if you are trying to monitor Injector Duty Cycles. Once I removed those two PIDs my duty cycle dropped back down to 1% at idle.

    Hopefully my donated Saturday will help others save theirs. END
    Last edited by TBMSport; September 5th, 2011 at 04:16 PM. Reason: RECHECKED PIDS-UPDATED
    Trailblazer "RS" 5.3L 6L80 4x4 & '07 TBSS LS2 6L90 AWD

  2. #2
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    Thanks for passing that info along. On my old PO8 4cyl ecm I would get duty cycles like that sometimes. And I had commanded afr pid selected. I never understood why it did that.
    1997 S10, 06 trailblazer SS LS2 swap, 4L70E trans, 76mm turbo. Factory ZQ8 suspension. 3.08, G80 w/a zexel. With a 0411 swap.

  3. #3
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    Quote Originally Posted by TBMSport View Post
    .....so I am venturing into territory that few if any outside GM have gone.
    ???

  4. #4
    Joe (Moderator) joecar's Avatar
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    Which injector pids were you using...? Some of the available injector pids may appear to work but they are incorrect for this application.

  5. #5
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    Joe I chucked the logs at this point as I couldn't trust the data. But I just went through clicking, mixing and matching and found that the valve temp one always through it off. But, I'm also finding that having this tricky cord seems to be causing some throttle hang up when in Pass Thru mode. I'll have to order a new cord and relog data to see if issues still exist.
    Trailblazer "RS" 5.3L 6L80 4x4 & '07 TBSS LS2 6L90 AWD

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