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Thread: Taking 3A of ground from EIO pin #5

  1. #1
    Tuner in Training
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    Taking 3A of ground from EIO pin #5

    I am connecting with an LC2 WB though the EIO. I want to insure the same reference ground with no ground loops.

    1) Does the MPVI Pro SUPPLY ground from the ODB connection to the EIO pin #5? (I think yes.)

    2) Will that supplied ground handle 3A current?

    3) Or is it OK to connect an additional chassis ground to EIO #5 without causing a gound loop within the MPVI Pro?

  2. #2
    Tuner in Training
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    After talking to Innovate, they suggest I do keep the WB operating all the time, even when the MPVI Pro is not plugged in. Choice (A) I supply a ground from the same point as I ground the WB to the EIO pin 5. That worries me because I might create a ground loop within the MPVI with one ground coming from the the ODB connection and another coming from the EIO. Choice (B) I ignore pin #5 on the EIO and give the MPVI Pro my WB output without trying to create a common ground. That may produce a bias in the MPVI Pro's interpretation of the WB output, although I believe the bias would be constant so I could program around it.

  3. #3
    I went with choice A in my current set up. I was also concerned with the ground loop you mention. Solution:
    1) Use a wiring diagram and exploded view of your vehicle to determine where the OBDII port on your vehicle gets its ground. Both grounds come from the same place in my car; a pretty large stud attaching the dash framework to the center tunnel.
    2) Install your WB using that same ground point.
    3) Use that ground point for pin #5.
    With all grounds tied back to the same exact point, overkill on the wiring (18ga), any ground issues are eliminated.
    2015 Cadillac Escalade ESV, 6.2L L86, 6L80e - AFM disabled

  4. #4
    HP Tuners Owner Keith@HPTuners's Avatar
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    The MPVI EIO ground should not be used to power any devices. It's purpose is to be used as a signal reference ground for inputs you connect.
    We got this guy Not Sure, ...

  5. #5
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    Agreed with you Keith, I will NOT take pin #5 as ground for powering my WB. But, my WB only has ONE ground attachment. The only way I can create a common ground for the MPVI and my WB signal output is to bridge the chassis ground that does power my WB and the EIO #5 pin. That does create the possibility of a ground loop within the MPVI Pro itself. What does HP Tuners say about connecting EIO pin #5 to a ground source?