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Old Nov 10, 2012 | 12:39 PM
  #1  
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I am putting a LM7 engine into a kit car I'm building and using an aftermarket LS1/LS6 harness and PCM to control it. The harness draws battery power from a connection at the battery terminal post on the starter. The way I want to wire the battery power is from the battery to a cutoff switch (on the Dash) and then to the starter which means that the PCM will lose power every time I turn off the cut off switch. Does the PCM need a battery feed for memory or can I cycle power to it?

I'd like the cut off switch to be able to kill power to entire car.

thanks

JC
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Old Nov 10, 2012 | 01:43 PM
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You will lose any learned fuel trims, idle control trims if you disconnect the power from the pcm all the time. If you can live with that then go ahead.
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Old Nov 10, 2012 | 01:51 PM
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Well, it would be nice to keep those, so I guess I'll have to connect those leads to the battery or the hot side of the cut off switch.

Thanks
JC
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Old Nov 10, 2012 | 06:48 PM
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The orange wire to the pcm is constant for memory
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Old Nov 10, 2012 | 08:57 PM
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The positive terminal from the starter is not a good place to feed the PCM.
When cranking the voltage drops too much across the wire, it can affect the PCM. It's better to hook another wire directly from battery
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