5.7 Alternator HELP!!!!

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BadAss71

BadAss71

Let's Go Brandon
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Ok so here is what's going on. I got a nearly new allternator from my dad off of his 5.7 truck engine. I have mounted it to the 440 in my dart. My question is, what do I need to do to get this thing to work! I have looked over the wiring diagram for the truck and found that one wire in the connector goes to ground and the other goes to the pcm. I can't figure out what exactly the ecm does to control the alternator. I have supplied 12 volts to that terminal and it full fields it, charges up to 17 volts! I'm thinking maybe it just needs a 5 volt reference? I would really like to figure this thing out. I posted this in the electrical section as well, but I figured maybe someone has done this and made it work with their hemi swap. Please help!
 
Have you used the voltage reg off the old car? Got to wire that in cause the 5.7 alt. is regulated thru the computer. Call Dave Weber at modernmuscle.biz, he'll help ya out.
 
So far as I know, the "new stuff" (believe it or not) has the regulator built into the ECM. If you can unground both field terminals, you can use a 70 and later regulator. If not, use a 69 and earlier
 
Thanks for the quick responses! I will do this tomorrow and update the thread.
 
Well I hooked it up thru the original voltage regulator, idle is fine, voltage sits at 14.7. Problem is, when the engine rpm is increased even a little bit the voltage goes way up to 16.5 to 17.0 volts! Any thoughts? I'm all ears!
 
ITS FIXED!! I replaced the 1 week old regulator with a new one and it works! Car runs way better than it did before also. Thanks for the input guys I appreciate it.
 
Glad to hear ya got it going.
 
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