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Thread: AEM Wideband transform question

  1. #1
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    AEM Wideband transform question

    I'm using an AEM 30-0300 wideband I've noticed that my wideband reads a little different (.5 to 1 point) than what HPtuners sees when using the proper transform ratio (V/.42105263)+7.3125. For instance my wideband gauge will say I'm at 14.2 and HPtuners says I'm at 15.1. I'm using the same formula that the manual states and what HPtuners has by default. I'm using AFR not lambda.

    I've changed the formula a little to more closely match what my wideband is actually showing me.(V/.45105263)+7.3125 (With in.2-.4 points now)

    Is this typical to have to manually adjust the formula for each wideband or do I just have a wonky one?
    I've done the resistor cal and free air cal with the same results.

    Thanks guys.
    05 Silverado Single Cab Long Bed
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  2. #2
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    u should leave the v/.42105263 as is but just change the +7.3125 to suit the voltage offset u must have that way it adds to correct the offset and not the calculation, what ever u are out by say .5 or 1 subtract that from the 7.3125 and it should dial it straight in

  3. #3
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    Great ill give that a try tomorrow thanks for the reply!

  4. #4
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    Quote Originally Posted by Ecobear86 View Post
    Great ill give that a try tomorrow thanks for the reply!
    How did you get it to work?
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  5. #5
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    Hello,
    I am now having similar issue with the 30-0300 using its analog out to the MPVI Pro on my C6 Corvette...
    The gauge reads 14.67 AFR but the analog/HPtuners reads 14.1. I did change the offset to make it match up but then while logging on the street the analog/HPTuners is reporting much leaner than what the gauge says.
    Gauge says, for example, 11.5 but analog reports 12.5.
    AEM is sending me a replacement but I fear it's going to do the same thing. Anyone else hit this?

    Thanks,
    Pj

  6. #6
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    I'm using the same WB but I'm using Lambda. No issues
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  7. #7
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    Thanks for the feedback....It is closer in lambda; gauge reports .99 while HPTuners reports .96 so, off by .3 instead of .6 with analog. Maybe a ground problem?
    Will post results with the replacement once I get it...

    Thanks,
    Pj

  8. #8
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    Quote Originally Posted by pjs View Post
    Thanks for the feedback....It is closer in lambda; gauge reports .99 while HPTuners reports .96 so, off by .3 instead of .6 with analog. Maybe a ground problem?
    Will post results with the replacement once I get it...

    Thanks,
    Pj
    No problem. Do you have the brown and white wires connected to your MPVI or MPVI2?
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  9. #9
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    Yep, brown and white to the MPVI Pro.

  10. #10
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    For the 30-0300 the brown wire is critical. If it is connected to ground, at the MVPI/ProLink, you can check the output with a voltmeter, between the white and brown wires, when the gauge reads ~14.7 at idle. The measured voltage should be very close to the range 3.00v-3.25v. If it is, the hardware is all working OK. And, the problem is in the conversion math.

    If you are using the MPVI2/ProLink, you should use the CAN data channels. And, avoid the math.

  11. #11
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    Quote Originally Posted by dr.mike View Post
    If you are using the MPVI2/ProLink, you should use the CAN data channels. And, avoid the math.
    CAN isn't available on the 30-0300.
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  12. #12
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    It is, if you are using the MPVI2 Pro Feature Set / ProLink.

    Not the OBDII CAN, like the 30-0334. But, the native AEMNet CAN of the 30-0300 is available over the ProLink's CAN lines. This is, actually better than the 30-0334/OBDII method. And, is saves bandwidth on the OBDII CAN bus.

    I do it all the time

  13. #13
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    Quote Originally Posted by dr.mike View Post
    It is, if you are using the MPVI2 Pro Feature Set / ProLink.

    Not the OBDII CAN, like the 30-0334. But, the native AEMNet CAN of the 30-0300 is available over the ProLink's CAN lines. This is, actually better than the 30-0334/OBDII method. And, is saves bandwidth on the OBDII CAN bus.

    I do it all the time
    Hmmmm. Ok. I may have to try this...

  14. #14
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    FWIW....I got the replacement gauge today and it does the same thing. I figured it would. Analog reading is way off even when I change to offset so that reading matches up but only matches at stoich. Once it goes WOT/rich, readings go off.
    Will try using serial method but had to order serial-to-usb adapter. Hopefully that works else I guess I can try the AEMNet CAN thingy...

    Thanks,
    Pj

  15. #15
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    The AEMNet CAN data is orders of magnitude better than the serial data. If you can possibly use CAN, go that way.

  16. #16
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    Looks like the 30-0300 does not come with an OBD2 connector. It has 2 CAN bus wires but not clear in AEM's manual how to use them with HPtuners or OBD2. I've been googling but no luck figuring out how to use it...
    Do I need to connect the 2 wires to an OBD2 connector somehow or do I have the wrong model of gauge?

    Thanks,
    Paul

  17. #17
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    Some luck....Found an HPT thread that says you need to use a passthru connector to splice in the two wires.

    https://forum.hptuners.com/showthrea...d-beta-testers

    Does that seem reasonable?

    Thanks,
    Pj

  18. #18
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    No. The 30-0334 CAN connects to the OBDII port. The 30-0300 & 30-0310 CAN wires connect to the CANH and CANL wires of the ProLink.

  19. #19
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    Thanks, So the CANH/CANL won't work with MPVI Pro? I don't have the MPVI2/ProLink...
    Last edited by pjs; 05-28-2020 at 02:57 PM.

  20. #20
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    Right. For the old MVPI PRO, you are limited to Analog or serial. UNLESS.... You have a post 2007 car. THEN, your 30-0300 can be re-flashed to 30-0334 firmware. And, THEN, you can connect it to the OBDII port. Just like a 30-0334.