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New Battery but starting being prevented

Old 01-15-2019, 07:22 PM
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Default New Battery but starting being prevented

I believe I've read thru the (many) threads on battery drain but I haven't found my particular issue. I originally thought my 1990 C4 was afflicted with the 'classic' battery drain* but having replaced the battery and been a bit more observant of the specific symptoms I now suspect that there is some electrical gremlin that is actively preventing start. Here is what happens:

Newly connected fully-charged battery - starts once and can be driven. Once it is turned off, on next start (even a minute later) dash lights flash and then there is a 'click' and then nothing. No attempt to start. Then the power from the battery seems to be shut off altogether. Nothing happens on key turn. Interior lights don't turn on. the voltmeter plugged into the cigarette lights goes dark (was 12.5 before last start attempt and 14+ during last drive). Now if I disconnect the battery (manual shutoff switch at negative terminal), wait 30 seconds (I'm not sure why I'm doing this, maybe I read it somewhere? but it seems it can't hurt), then turn it back on. I can now start the car and run it. Until I turn it off. Then the process repeats.

Is some anti-theft something or other being triggered that then gets re-set when the battery is disconnected? Something else I should try?

*I believe there is ALSO a battery drain issue. But having read all the other threads I am now educated enough to at least start troubleshooting that once I get this sorted.
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Old 01-15-2019, 08:50 PM
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sound like you have a bad connection I would check the ground cable where it mounts to the body. your losing the battery you need to check battery cables
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Old 01-16-2019, 02:24 AM
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First and foremost change your DME relay in the main fuse box.
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Old 01-16-2019, 03:33 AM
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This seems to be a bad connection to the battery. I'd start with checking all cables and couplings from both poles to the related circuitry.
To find a current thief, here's a DIY check list and overview of the most common issues.
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