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Thread: Dumbest HPTuners ProLink to PLX wideband Question EVER

  1. #1
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    Dumbest HPTuners ProLink to PLX wideband Question EVER

    Wideband.jpg
    I haven't found a wiring diagram to connect my HPT Pro link to the PLX wideband. I think the ProLink red wire goes to the lower right section of the 4 connector
    socket but is that the only one? Is the black a ground? If so where does it go? Help!

  2. #2
    Advanced Tuner
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    Be really careful wiring up the PLX. Some of them have a ground wire on the 4-pin connector, lower left. And others have +8V on that pin. Depends on when they were made. Connecting +8V to ground would be what electrical engineers refer to as "A bad thing". I'm pretty sure the ground pins on the SM-AFRs that actually are grounds, are low-impedance "Hard Ground". So, connecting a hard ground ( on the WB ) to another hard ground ( on the ProLink ) can cause a ground loop. Which can lead to a lot (more) of noise.

  3. #3
    Potential Tuner
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    Yikes! Mine does have +8V on the lower left of the 4 pin connector. Any instructions?

  4. #4
    Advanced Tuner
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    Yeah. I think both of mine have the +8v pin, too. That catches a few people.

    I'm pretty sure that all you can do ( short of making some OPAMP based offset compensation circuit ) is to connect the Red wire to the WB pin ( lower right ). And, leave the black wire floating/unconnected. Do cover it with electrical tape, though, to prevent shorts.

    IIRC, once, I tried grounding an input to the aluminum case of the PLX. That just made things worse.

  5. #5
    Tuner
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    not to revive an old thread... but it got me just now also.

    Had the prolink red wire on the WB pin (lower right) of the PLX connector and had the black ground wire on the "gnd" pin on the lower left of the connector.
    was getting a funky AFR of 10.5 on VCM Scanner and it wasn't changing.

    I have another unit that uses the PLX to monitor the AFR through the serial output and it was working normally.
    I checked the "gnd" pin on the PLX connector with my multimeter and it wasn't a ground, and had a about +1.6v on it when measured to battery ground.

    removed the black pin from the connector and my AFR's in VCM scanner are now reading normally!

    This was the only post I found mentioning this issue anywhere on the internet!
    so thanks for the info!

  6. #6
    Tuner in Training jimmyZJ's Avatar
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    Apr 2021
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    hi, have a look page 4, they are showing additionnal capacitors
    https://download.tpl.one/PLX/manual/SMAFR.pdf