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Thread: Current draw on SBECs

  1. #1
    Supporting Member Turbo Mopar Contributor
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    Current draw on SBECs

    I have noticed that functionally similar SBEC and SBEC2 will draw different currents.
    I have tested approx on dozen SBEC and SBEC2, their standby current is approx, 1mA this is with pin#3 (battery) ON.
    The next test is to place IGN power to pin9 (IGN) this varies from 0.1A to 0.5A. I was not expecting this large of a range so I thought to change the electrolytic caps just for fun as my LCR determine the existing caps are in good shape.

    Has anyone noticed this before and ,if so, were you able to repair/fix
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  2. #2
    turbo addict
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    Re: Current draw on SBECs

    Could this just be a symptom of old components that already had a fairly wide quality range?

  3. #3
    Supporting Member Turbo Mopar Contributor
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    Re: Current draw on SBECs

    Quote Originally Posted by Reaper1 View Post
    Could this just be a symptom of old components that already had a fairly wide quality range?
    I agree your statement is possible but I am very surprised the current draw difference is so large. Yes 30 year old used electronics, we don't know the history.
    Last edited by chromguy; 06-08-2020 at 06:26 PM.
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  4. #4
    turbo addict
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    Re: Current draw on SBECs

    OK, I am about to show some ignorance here. Is it possible that there's more "stuff" idling due to architecture or protocols?

  5. #5
    Hybrid booster Turbo Mopar Contributor 85lebaront2's Avatar
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    Re: Current draw on SBECs

    Miles, if the difference is between the SBEC and SBECII, it could be other external items it is capable of talking to as Chrysler was evolving their computer systems finally ending up with the NGC in the mid 90s many of the 1990 on models had anti-theft and security alarms in the BCM. This might be various routines running in the background.

  6. #6
    Supporting Member Turbo Mopar Contributor
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    Re: Current draw on SBECs

    Quote Originally Posted by Reaper1 View Post
    OK, I am about to show some ignorance here. Is it possible that there's more "stuff" idling due to architecture or protocols?
    Well I investigated a bit further and if I remove the EPROM chip the current drop significantly. From this I would guess the program in the EPROM is turning on a few circuits such as the low/medium current drivers. I will need to try additional experiments

    Bill it does not appear to correlate to ECU type.
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  7. #7
    Hybrid booster Turbo Mopar Contributor 85lebaront2's Avatar
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    Re: Current draw on SBECs

    Miles, could it relate to application, say TBI vs Turbo vs V6? As we have already determined the increase in the number of control ICs as the SBEC for a turbo has 6 of them, depending on what else is used, there could possibly be 11 or 12 of them. On the 3.3/3.8L with sequential injection and DIS, 6 for injectors, 3 for the coil pack, one for alternator field (maybe). That puts the board at 10 of these.

  8. #8
    Supporting Member Turbo Mopar Contributor
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    Re: Current draw on SBECs

    Quote Originally Posted by 85lebaront2 View Post
    Miles, could it relate to application, say TBI vs Turbo vs V6? As we have already determined the increase in the number of control ICs as the SBEC for a turbo has 6 of them, depending on what else is used, there could possibly be 11 or 12 of them. On the 3.3/3.8L with sequential injection and DIS, 6 for injectors, 3 for the coil pack, one for alternator field (maybe). That puts the board at 10 of these.
    Yes, it is possible but I have not see enough data yet to draw a conclusion.
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

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