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Thread: Aem 30-0334

  1. #1
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    Aem 30-0334

    AEM 30-0334
    Using this on my car as analog. Im running positive and negative both to the analog outputs to hpt

    Right now in on resistor calibrate (auto calibrate). When its calibrated it reads 19.9 but hptuners reads 17.9.

    Running the cars it doesn't really switch much from 15 to 17 afr on the scanner even with command changes and by the smell of it is def not lean, the guage also reads .5 to 2.5 even tho set up for AFR.

    My next step is maybe to do a free air calibration.
    Anybody have experiences with this.

    Also should i have run my anolog positive from the gauge and then the negative to a dedicated ground or back to the gauge analog negative?
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.

  2. #2
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    Free-air cal will not help this one. You do need to run the analog negative to the ground on the MPVI2 so the the gauge and the scanner will agree on what ground level is.

  3. #3
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    Quote Originally Posted by dr.mike View Post
    Free-air cal will not help this one. You do need to run the analog negative to the ground on the MPVI2 so the the gauge and the scanner will agree on what ground level is.
    This is an MPVI1 but either way. Whats your opinion on the other issue? Gauge issue? Somthing else?
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.

  4. #4
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    Something is off, there. Can you maybe post a video of the issue ? rCal should be fine for almost all conditions.

    To test it,

    1. Set the gauge to rCal
    2. Set the gauge to display o2%
    3. with the sensor out in fresh air, note the display value. It should be between about 19% to 21% pending the altitude.

  5. #5
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    Quote Originally Posted by dr.mike View Post
    Something is off, there. Can you maybe post a video of the issue ? rCal should be fine for almost all conditions.

    To test it,

    1. Set the gauge to rCal
    2. Set the gauge to display o2%
    3. with the sensor out in fresh air, note the display value. It should be between about 19% to 21% pending the altitude.
    Come to think of it there is a small possibility it may have been in O2% mode.
    It did display 19.9.
    Car in it displayed. 05 to 2.5.
    I guess 0.0 indicate rich which would def coincide with the Car being rich..

    How does 02% work overall?
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.

  6. #6
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    A lot like you described. 0.0% would be everything richer than 14.7afr ( lambda 1.0 , or, zero free oxygen )
    0.05 to 2.5% would be on the lean side, usually with 2.5% ish only happening on decel.

    With the sensor in in open air you get 20.9%, corrected for altitude, barometer reading, and air temp. That's usually in the 19% to 21% range. But doing a free-air-cal will force the reading to 20.8 or so. Hence, using rCal mode.

    If the gauge is in AFR or lambda mode, it will display "- - - -" with the sensor in fresh air, instead of 19% - 21%

    The analog output never changes functions and is always outputting based on Lambda values.

  7. #7
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    Quote Originally Posted by dr.mike View Post
    A lot like you described. 0.0% would be everything richer than 14.7afr ( lambda 1.0 , or, zero free oxygen )
    0.05 to 2.5% would be on the lean side, usually with 2.5% ish only happening on decel.

    With the sensor in in open air you get 20.9%, corrected for altitude, barometer reading, and air temp. That's usually in the 19% to 21% range. But doing a free-air-cal will force the reading to 20.8 or so. Hence, using rCal mode.

    If the gauge is in AFR or lambda mode, it will display "- - - -" with the sensor in fresh air, instead of 19% - 21%

    The analog output never changes functions and is always outputting based on Lambda values.
    Alright awesome thank you. Makes much sense. If it's reading over 0% then its reading lean at idle which makes sense with a large cam and a good amount of overlap.
    Thank you very much.

    Does it meant its reading the amount of extra oxygen in the exhaust as a percent more of lamabada?
    Last edited by anniversaryss; 06-12-2019 at 08:01 PM.
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.

  8. #8
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    The only measurement it knows how to make is the percentage of oxygen at the sensor tip. AFR and lambda are just calculated from that number by a formula. In reality, the o2% can be negative, when there is zero oxygen, and there is left over fuel ( rich ). But, showing a negative number freaks people out. And, Bosch ( the sensor manufacturer ) does not specify the negative side of the oxygen curve in their tech data; only lambda. So, anything with zero free oxygen shows 0.0

  9. #9
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    Might have been 4 weeks ago but my issue was i had it set for O2% now its good on AFR
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.