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Thread: Returning to cl maf-problems

  1. #1
    Lifetime Member Gregs's Avatar
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    Default Returning to cl maf-problems

    I finally got my wideband signal rerouted the the pcm to simulate the nbo2 so i did a little tweeking to the sd tune i've been running so i could go back to closed loop. On the test drive everything was going good for a few minutes then the afr started jumping all over the place. it would jump around from 17.5:1 then to 10:1 while i was on the highway. I pulled off the road and loaded up my previous sd tune to get me home. I'm home now looking over this tune and i can't seem to figure out why things aren't working right. Any help would be soo much appreciated!

    I've attached the SD tune that works great and the CL tune thats not working out
    Attached Files Attached Files

    03 Silverado 5.3 ECSB 4x4 Z71
    Comp Cam 206/212 .515/.522 112 lSA, hardened rods with LS9 springs

    2010 Tahoe VVT AFM 5.3
    Stock for now

  2. #2
    Lifetime Member 5.7ute's Avatar
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    Do you have a log of this occurence? Are you certain that this isnt the normal rich/lean switching that occurs during closed loop?
    The Tremor at AIR

  3. #3
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Gregs:

    When you say you were SD tune and then returning to Closed-loop...

    Wasn't your MAF enabled on both tunes?
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  4. #4
    Lifetime Member Gregs's Avatar
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    5.7ute:
    Unfortunately i don't have a log... i was monitoring not recording i'll go out again and see if i can get a log of it doing the same thing. it definitely wasn't switching around it was pegged at 10:1 or less for a little bit thats when i pulled over.

    weathermanshawn:
    I thought it didn't matter as long as it was forced into ol using b4505 so i didn't change it...my bad

    03 Silverado 5.3 ECSB 4x4 Z71
    Comp Cam 206/212 .515/.522 112 lSA, hardened rods with LS9 springs

    2010 Tahoe VVT AFM 5.3
    Stock for now

  5. #5
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    I am not sure how that would work. You were running open-loop with the MAF enabled, but B0120 (Airflow Calculation at 7000 Rpm's)?

    Did you originally tune the VE Table or MAF? Because you would have been mixing the Airflow Calculations from both the VE Table and MAF. Normally a SD tune will have the MAF disabled, and if running MAF only (OLMAF) in open-loop you need to set B0120 to 400 Rpms.

    If your wideband is correct, that may be the problem. You might need to disable the MAF as indicated in the AUTOVE Tutorial and tune just the VE Table airflows. I don't think you can run open-loop in that fashion..so when you went back to closed-loop your Trims probably exceeded their limit(s).

    We probably need another tuner to do a double-check..but your open-loop tune shows MAF-enabled, but airflow calculation did not put it in OLMAF..And it was not in SD mode because your MAF was enabled. That would have been some significant discrepancies in the airflow models..hence your fueling problems..

    Did I describe that right?
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  6. #6
    Lifetime Member Gregs's Avatar
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    wow thanks weathermanshawn you described that perfectly. I'm not surprised one bit that it was my screw up. Well it looks like i'll have to go back to the beginning and get the ve table squared away first. Thanks for the help!

    03 Silverado 5.3 ECSB 4x4 Z71
    Comp Cam 206/212 .515/.522 112 lSA, hardened rods with LS9 springs

    2010 Tahoe VVT AFM 5.3
    Stock for now

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