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Thread: am i shooting for stoic durring choke?

  1. #1
    Fuel Injected!
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    am i shooting for stoic durring choke?

    Noob question.
    Am I shooting for stoic during choke?
    Ron

  2. #2
    Super Moderator dave w's Avatar
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    Usually there is a choke table AFR vs. Temperature. Colder temperatures required richer AFR's. Starting at -40F would be very close to 9:1 AFR. Starting at +140F would be very close to 14:1 AFR.

    dave w

  3. #3
    Fuel Injected!
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    Thanks. What I meant to ask was:
    Should I be aiming for 400's o2?

  4. #4
    Super Moderator dave w's Avatar
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    Quote Originally Posted by f85gtron View Post
    Should I be aiming for 400's o2?
    I don't think that plan will be successful.

    I think a more successful plan for adjusting the choke, would be to use actual AFR's. I'd use a Wide Band O2 (WBO2) sensor to measure AFR's. The AEM 30-4110 http://www.aemelectronics.com/?q=pro...uego-afr-gauge is a good WBO2. Amazon pricing: http://www.amazon.com/AEM-30-4110-UE...ywords=30-4110

    dave w

  5. #5
    LT1 specialist steveo's Avatar
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    you can't really tune and aim for a narrowband o2 voltage.

    you need to let the ecm fiddle around with the o2 to try to attain stoich, then use its trim calculations to base your fueling modifications on.

    if you want an AFR other than stoich, tuning your base fueling tables so they hit stoich using trims then make sure the fuel is multiplied in your enrichment table or whatever usually gets you close

  6. #6
    Fuel Injected!
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    To be more basic, narrowband O2 sensors are only useful for measuring stoichiometric fuel or when lambda = 1. Stuff like cold enrichment, accel enrichment and power enrichment run with a lambda under 1 so narrowband O2 are useless to measure it.

    Once you get the VE and MAP tables right then the PCM can calculate the different enrichments correctly.

  7. #7
    Fuel Injected!
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    Ok Thanks. I'm learning as i go. You guys are helping me go.

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