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  1. #1

    Default Wideband in place of narrowband

    Iím installing my wideband and my shop wonít be able to squeeze me in to get the bung welded in for a while.

    As of right now, I just want to hook it up for to do some data logging to get my tune figured out.

    Will there be any adverse affect to putting the wideband in place of one of my narrowband on a header collector and just disconnecting that narrowband for tuning? I have an AEM and am using EEHACK.
    1994 Trans Am GT, stock 28k mi bottom end LE2 H/C/I , 1.6rr, LT4 KM, moroso cai, jet hot lts, hooker y-pipe, slp powerflo, 37# inj, 255 pump, built 4l60e, 2800 stall, spohn/hotchkis/qa1 suspension etc etc.

  2. #2
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    Default

    Do you have an open loop tune? If not, an O2 sensor hanging in mid-air will screw up the fueling on that bank. Disconnecting the sensor would prevent the PCM from entering closed loop. With an open loop tune, the stock O2 sensors are just excess baggage.

    Some wide-band controllers have the ability to emulate a narrow-band signal, converting the 0-5 volt wide-band signal to an equivalent 0-1 volt narrow band signal, and to do that simultaneously with the wide band output. You would just connect the harness wires for the stock sensor to the terminals on the controller for the narrow-band (emulated) output.

    94 Formula A3+1: 381ci forged stroker - Callies Stealth, Oliver 5.85 billet rods, BME nitrous pistons / CNC LT4 heads / Comp Cams solid roller / TH400+GearVendors OD / 4.11's/Strange 12-bolt / 300-shot (dry) N2O / Spohn Suspension / 6-pt roll bar /AutoMeter instrumentation / MoTeC M48 Pro engine management system /a few other odds 'n ends.

  3. #3

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    I will look into see if mine have the ability to emulate. If not, does an open loop tune give sufficient data, or is it better to have a closed and open loop tune.

  4. #4
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    You want to log data with the type of tune you plan to run.

    A/F ratio in closed loop is subject to PCM adapting to maintain a given A/F ratio (typically 14.7:1) at part load, by using learned long term fuel trims (LTFT), based on O2 sensor feedback. When you go into power enrichment (PE) mode (roughly WOT) the PCM usually uses the learned corrections (there are exceptions), with a richer target A/F ratio. The O2 sensors are no longer used for adjustments. You can override with a “BLM (LTFT) locker”.

    In open loop, the PCM simply ratios fuel flow to mass air flow, with no corrections based on feedback from the O2 sensors. You don’t even need the O2 sensors.

    In both cases you can tweak things like the MAF calibration, or VE tables (if you run aspeed-density tune), based on the wide-band readings in the log. Point is, if you plan to run a closed loop tune, you aren't going to learn a lot from an open loop log.

    94 Formula A3+1: 381ci forged stroker - Callies Stealth, Oliver 5.85 billet rods, BME nitrous pistons / CNC LT4 heads / Comp Cams solid roller / TH400+GearVendors OD / 4.11's/Strange 12-bolt / 300-shot (dry) N2O / Spohn Suspension / 6-pt roll bar /AutoMeter instrumentation / MoTeC M48 Pro engine management system /a few other odds 'n ends.

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