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Thread: AEM X-Series Intermittent Logging Issues

  1. #1
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    AEM X-Series Intermittent Logging Issues

    Hi,

    I'm getting pretty frustrated with my AEM 30-0300. Admittedly, my initial wiring job was terrible, so I ripped the dash apart, rewired all my gauges with Deutsch connectors, good crimpers, loom, and a ground bar. For a few drives I thought that all my problems were eliminated. Then things went haywire again. The signal on the scanner was logging AFR at max lean or max rich and only seemed to change when I was turning the key on and off. The gauge and sensor seem to work just fine because the gauge always displays a believable ratio. My issue is only in the scanner.

    I attached the AEM directions. The brown wire is grounded, white wire is connected to the red wire on the pro link, and pro link black is grounded. The second attachment shows my funky AFR graph. I think my next step is to unplug the pro link and put a meter in place of it. One lead will be on my gauge's white wire and the other on ground. I figure if I see anything between 0 and 5 V with the engine running that the gauge is working just fine and that I have something really goofy going on with my HP tuners. If I only see 0 OR 5V then my gauge output is faulting.

    What do you think? Am I on the right track?

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  2. #2
    Connect the brown wire directly to the black wire on the pro link. Don’t ground them with the rest of the vehicle.

  3. #3
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    Quote Originally Posted by crankz1 View Post
    Connect the brown wire directly to the black wire on the pro link. Don?t ground them with the rest of the vehicle.
    Thanks for the reply. Are you saying that the pro link is grounded through the MPVI2 at the DLC?

  4. #4
    I can only assume it is. I look at the pro link as inputs to the MPVI2. In this case analog + and analog -. Which you connect the analog outputs from the AEM to.
    That's exactly how I run mine and it works perfectly.

  5. #5
    That's not necessarily to say that you shouldn't be able to have it all on a common chassis ground though. I just don't know. Anything else that might introduce noise to the chassis ground would certainly effect the signal to the MPVI though.
    I just look at them as dedicated inputs and outputs, and wire as such.

  6. #6
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    Quote Originally Posted by crankz1 View Post
    That's not necessarily to say that you shouldn't be able to have it all on a common chassis ground though. I just don't know. Anything else that might introduce noise to the chassis ground would certainly effect the signal to the MPVI though.
    I just look at them as dedicated inputs and outputs, and wire as such.
    I guess I just find it odd that the link has two analog input channels, but only one signal ground. Then again, I guess grounding the signals to the same place just eliminates another floating issue?

    Just to get this straight. You don't "ground" either of those wires then. You just connect them like this?
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    Not like this? This is how I currently have it.
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  7. #7
    Senior Tuner
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    I've been having problems with the output not working for several minute into some drives even thought the wideband is warmed and displaying legit values. I contacted AEM support and they told me to wire it like you originally had it. Have you wrote to them and asked?
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  8. #8
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    Interesting. I have not not tried asking them just because the HPT issues didn't quite fall into their wheelhouse. I still haven't done my meter test, but I probably can tonight when I get home. I suppose the outcome of that might prompt an email to AEM.

  9. #9
    Quote Originally Posted by V6Buicks View Post
    I guess I just find it odd that the link has two analog input channels, but only one signal ground. Then again, I guess grounding the signals to the same place just eliminates another floating issue?

    Just to get this straight. You don't "ground" either of those wires then. You just connect them like this?
    2.png



    Not like this? This is how I currently have it.
    1.png
    Correct. I do not ground the analog - wires. I connect it just like your first diagram.

  10. #10
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    The brown wire on the 30-0300 is NOT a ground wire. It is an input to the gauge that the WB uses to figure out what level "ground" is at, where the measurement is being made ( Prolink A/D ). So, it should be wired, directly, to the pro-link BLACK wire. And the Prolink BLACK wire should NOT be forced to a different ground, than its internal ground, which it gets from the OBD2 port.

  11. #11
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    Quote Originally Posted by dr.mike View Post
    The brown wire on the 30-0300 is NOT a ground wire. It is an input to the gauge that the WB uses to figure out what level "ground" is at, where the measurement is being made ( Prolink A/D ). So, it should be wired, directly, to the pro-link BLACK wire. And the Prolink BLACK wire should NOT be forced to a different ground, than its internal ground, which it gets from the OBD2 port.
    That was a great way of explaining it. Thank you! I will begin rewiring it tonight.

  12. #12
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    I agree with you. This is what AEM tech support said to me though. I never did go though with it. I got another gauge on standby in case it does this to me again.

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  13. #13
    I think I have the same issue as my wb all of sudden want read past 7.58 afr and has the car super rich. I am not following that last statement on the ground wire. I have my pro link red to white going into a 5amp fuse and brown to black black being grounded to the negative battery terminal. Wb and scanner were spot on until a few weeks ago. Aem advising to move the red wire to the positive battery terminal to see if it fixes and to rule out any other possible interference as the wb may be bad. What are your thoughts as I have read a lot of topics with you giving great info.