Battery has less then 12v, Cranks but won't start, Is this normal
03-19-2015, 05:10 PM
#1
Battery has less then 12v, Cranks but won't start, Is this normal So the Porsche sat for about 2 weeks. I knew the battery was a little weak. I tried to start, cranked fine for about 5 seconds, About 3-4 attempts, then starter got weak, checked battery voltage it was 11.3v. I disconnected battery and put on charger for about an hour. Hooked up fully charged battery and started right away. IS this normal for these computer controlled motors or do I have something hooked up wrong.
03-19-2015, 05:37 PM
#2
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Yea, this sounds normal. You have to remember, your voltage will be lower while you are cranking compared to when it is just stationary. I don't remember the exact voltage, but these ECMs need to see something like 10.2-10.5v for them to even turn on. With the battery weak, it's pretty likely your voltage was dipping below that threshold while cranking.
03-19-2015, 05:51 PM
#4
Thanks, that takes a load off, thought maybe I needed an extra wire or something during starting, since I'm running the Porsche and the GM ECU. Starter wire is the factory Porsche wire and the other engine wiring is GM stand alone ECU.