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Thread: Help Reading Data Log

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  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?

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