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battery parasitic drain

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    battery parasitic drain

    My apologies for coming very late on this thread however I just found it over the weekend while searching the web for E30 battery current drain issues.

    I was wondering if digger resolved this issue and what was the root cause as I have a similar issue going on in my car.


      i never found a smoking gun i think the battery had been discharged and not recharged properly while at a shop and just need a proper deep charge, i did have a vaccum pump wired incorrectly which i fixed but it had been that way for years without major issue so wasnt the root cause.
      the last time it got drained was being towed when igntion was left on for a while about a year ago. i havent had any drain issues since it was recharged properly but havent checked the current draw.
      Last edited by digger; 05-06-2019, 04:13 PM.
      89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

      new build thread


        battery parasitic drain

        Many thanks,
        I appreciate the follow-up response,
        I clearly have a different issue now as the fully charged battery is Ok but nothing is happening at the ignition key in the start position.
        Looks like another miss spent weekend coming up.


          Folks, if you dont mind me reviving this.
          i have a stock 325e from 1984. Battery dies in a short period of time. 178mA draw.
          removed all fuses and nothing changes
          in the junction, i disconnected everything and when connecting either the alternator/starter cable or the wiring harness to the engine/ecu/etc i get the draw.

          any ideas?

          i pulled the entire harness, cleaned every connector and ground, connected again and still…

          thanks in advance!


            So with every fuse pulled, you still have 178mA draw?

            Time to use the Electrical Troubleshooting Manual to figure out what is directly connected to the battery that could be causing the issue.
            1987 - 325i Convertible Delphin Auto [SOLD], 325i Convertible Delphin Manual [SOLD]
            1989 - 325i Convertible Bronzit m30b35 swapped [SCRAPPED], 325i Sedan Alpine Auto[DD]
            1991 - 325i Coupe Laguna Manual [Project], 535i Sedan Alpine [SCRAPPED]


              Have you bench tested the alternator
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