Thread: Chevy 400 transplant/engine wiring

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Hey guys me again, I just planted a chevy 400 into my 79 trans am. I've got it running great besides the the rear main leak. The other problem is how exactly the wiring should go. I have the alternator wired wrong I think. I have tried it a couple of ways and as soon as I turn on the headlights it wants to die. Also when I pull the battery cable off when the car is running it will instantly die. Does anyone have a good engine wiring schematic for a chevy engine. I know this is something simple I just can't get it right. I have the schematic for the Trans am but I don't understand the whole alternator charging the battery deal. Can I run a direct line to the battery from the alternator battery terminal. Please help I would really like to get out of the garage.

As soon as Streets reads your post I'm sure you'll have more schematics then you know what to do with. He has links to a bunch of them.

Streets where Are you.... I heard you had some wiring diagrams.

Do some reading here and you will gain a whole lot of understanding how things work:

http://www.madelectrical.com/electrical-tech.shtml

Pat

That's a very informative site Pat. I read through most of it and Learned how to wire a one wire alternator and learned where the main power wire goes on a three wire alternator. I learned that the three wire system is better and why it's better. The only thing they left out was where do you hook up the other two wires on the three wire system. I think that's what onemangang needs to know. I looked in my Motor's manual and couldn't find it there either. Does anybody know? or should he just go buy a one wire alternator?

Thanks Stu-I read the all that info but what I really need to know is how I apply this wiring diagram here (or Attachment) from the 403 olds engine to the 400 chev motor. I really just need to know which wire goes to where. I can't figure out how to send the attachment. I paste the file on the attach file box and then hit preview but it just erases.
Help.

Let's try these schematics again.

Looking at your diagram

The terminal on the alternator marked BATT goes to the power distribution lug. The red sensing wire from the two wire plug also goes there. Do not take a short cut and wire the red wire to the BATT. This will give your alternator false readings. I believe the remaining brwon wire goes to your ignition, in this diagram it shows it going into the bulkhead connector.

I hope that helps.

Pat

I have done the alternator wiring thing this way since they first came out.

10 GA wire from the starter, where the battery cable attaches, to the power lug on the alternator.
The regulator plug has two wires on it, one 12 ga, and one 16 or 18 ga.
Run the 12 ga wire from this plug to the power lug on the alternator that the main power goes.
The remaining smaller wire can either be cut, or it can be run to an idiot light.
If you use the idiot light, it must be a two terminal socket. One wire runs to the fuse panel, to a switched fuse. The other is connected to the small wire from the alternator.
The double terminal light does two things, it lets you know when the alternator is charging, by going out, and it keeps the electrical current from returning to the system and keeping the vehicle running after the key is shut off.
Like I said earlier, this has worked for me for years, and I have NEVER had a problem.