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Thread: Help Reading Data Log

  1. #1
    Fuel Injected!
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    Help Reading Data Log

    I have completed the TBI conversion and have my rig running almost where I want it. My symptoms are as follows. I have an unidentified stumble off idle that sometimes extends to the 1-2k RPM range. It generally is worse when colder. Keep in mind our ambient air temps right now are in the single digits to below zero. The other day it was in the mid 20's and I took it for a drive hoping to log some data. The truck ran pretty well, and I could not replicate the stumble when recording.

    My question is, if I can record a stumble, can anyone here play back the log file and help me identify what might be causing the problem? I've replaced cap, rotor, plugs, wires, coolant temp sensor, and TPS. My fuel pressure is good and the injectors are spraying a nice even pattern. New ECM and AFI harness. No codes.

    I'm so close to having this project complete but I don't want to just throw more parts at it.

    Thank you!

  2. #2
    Fuel Injected!
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    In addition, I've rebuilt the TBI and the system has both knock and EGR removed and de-programmed from the chip.

  3. #3
    Super Moderator dave w's Avatar
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    Sometimes the Acceleration Enrichment (AE) which is similar to a carburetor "Pump Shot" needs adjustment to correct for an unidentified stumble.

    My method to adjust AE is with a Wide Band Oxygen Sensor (WBO2). Ideally the Air Fuel Ration (AFR) during AE would be between 12.5 - 13.5.

    Without a WBO2, its a "Best Guess" if an unidentified stumble is an AFR being Rich / Lean AE fuel table.

    Then again it could be spark advance causing an unidentified stumble. Having a WBO2 helps identify if its a fuel table or spark table causing an unidentified stumble.

    dave w

  4. #4
    Fuel Injected!
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    Is there a specific WBO2 you recommend?

  5. #5
    Super Moderator dave w's Avatar
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    Quote Originally Posted by mtbraun View Post
    Is there a specific WBO2 you recommend?
    http://www.aemelectronics.com/produc...uego-afr-gauge

    dave w

  6. #6
    Fuel Injected!
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    Thanks for the recommendation. If I hook this up, can it be incorporated into Tuner Pro datalogging? If so, how is this done?

  7. #7
    Super Moderator dave w's Avatar
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    Quote Originally Posted by mtbraun View Post
    Thanks for the recommendation. If I hook this up, can it be incorporated into Tuner Pro datalogging? If so, how is this done?
    http://www.moates.net/apu1-autoprom-....html?cPath=64

    https://www.youtube.com/watch?v=vBpDu6l7GPE

    dave w

  8. #8
    Fuel Injected!
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    I ordered a WBO2 yesterday. Will the datalogging component you referenced above be required to reburn the chip (if necessary) once I get the WB hooked up? I can't justify the cost of the logging system above so hoping we can tune with the WB only.

  9. #9
    Super Moderator dave w's Avatar
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    Tuning requires burning chips. More often than not, several "Trial and Error" corrections to the chip programming are required to "Tune".

    dave w

  10. #10
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    Quote Originally Posted by dave w View Post
    Tuning requires burning chips. More often than not, several "Trial and Error" corrections to the chip programming are required to "Tune".

    dave w
    I understand. What I'm wondering is if we can tune the truck with just the WB, or if the APU1 system is needed to capture the WB data for re-burning. I would like to try to tune with just the WB.

  11. #11
    Super Moderator dave w's Avatar
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    I'm thinking you have the 1227747 TBI computer? If you have the 1227747 computer, the APU1 is needed to Capture / Insert the WBO2 information into the data log.

    dave w

  12. #12
    Fuel Injected!
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    Quote Originally Posted by dave w View Post
    I'm thinking you have the 1227747 TBI computer? If you have the 1227747 computer, the APU1 is needed to Capture / Insert the WBO2 information into the data log.

    dave w
    Correct I have the 1227747 ECM. We're just gonna have to wing it and burn multiple chips if necessary. I can't justify the cost of the APU1 system for this project. What is strange is that the symptoms get MUCH worse the lower the air temperature. When driving a couple days ago in +25F weather, it actually ran pretty decent. Only cut out a couple times. Today it is -5 and it cuts out and is very saggy in the 1000-1500 RPM range. That suggest to me it may be air/fuel related rather than spark.

  13. #13
    Super Moderator dave w's Avatar
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    Attached is a screen shot for the AE parameters used for the 1227747 computer.

    Let the Chips begin.

    dave w
    Attached Images Attached Images

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