Fooling the ECM with 1 wire alternator -
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post #1 of 4 Old 05-30-2020, 08:46 PM Thread Starter
92 Green YJ
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Location: Spring Valley, San Diego, CA
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Fooling the ECM with 1 wire alternator

Hey all. Thought I might get a bit more traffic and response putting this in a separate post from my build thread.

So with the engine now running, I have a check engine light due to the alternator not being seen by the ECM. Itís a 92 YJ and I put in a Powermaster 170 amp 1 wire alternator. (Internally regulated) so I removed the factory wiring for the alternator for the most part. Left some tails coming out of the ECM but thatís it.

Does anyone know what the alternator field wire is looking for? Can I ground it or tie it to 12 volts to trick the ECM to thinking the original alternator is there and functioning normally? Need the CEL off so I can smog it.

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post #2 of 4 Old 06-03-2020, 04:18 PM
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Pretty sure the ECM needs those 14.2 volts, which it then REGULATES (bc its INTERNALLY REGULATED) to the injectors and things like that. Not sure so still waiting for someone else to chime in..
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post #3 of 4 Old 06-03-2020, 06:19 PM
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Correct LenVino.
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post #4 of 4 Old 06-03-2020, 06:20 PM
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Various values of resistors suggested to simulate the field winding coil to the computer testing it.

Perhaps try the 1 k resistor as some said it worked.
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