I pretty much have the lt1 wired in but I have a few questions regarding the alternator.
The Lt1 alternator has a large red wire on a ring terminal all by itself.
1) Does this go to the Battery directly or to the B+ on the starter?

Next I have a slightly smaller red wire then the original one around the ring terminal.

2) Does this go to the large red wire from my original harness specific to the 87 4bbl harness in my car?

Next I have two brown wires from the Lt1 alternator and on the original plug to the stock alternator is a brown and brown/white wire.

3) How are these supposed to be connected?

I did a search and got more confused as some people talked about putting in resistors and others said it was unecessary?

Also, can someone please post a pic of the original connector for the temp gauge(4bbl) and possibly the a/c connector?

Thanks for any help in advance.

 

I have the same issue, but i also have something else happening. when i crack the lt1 after about 2mins the fans comes on. i'm using the temp switch from the 305 carb'd. it's a 180 degree switch and is about 5 or 6 mnths old.
Not so sure if the ecm is doing the turning on or what?

 

If your coolant temp sensor (the one at the water pump) isn't plugged in the fans turn on right away and stay on.

 

the switch is at the water pump and the is plugged in, but the fan still comes on(the system is pled; the res. and rad are both full).
still

 

I do know that the sensor on the water pump itself is only for the ECM and necessary for the Lt1. For the gauge in the car, the sensor should be on the passenger side head. I just need to figure out which color wires from the original harness went to it.

 

This may not help soo much.

I installed a '95 LT-1. The stock altenator had only two wires. A main power wire and a smaller single red wire.

The main power wire was integrated into the stock wiring harness at the positve battery terminal. However, I believe there is a diode built into to that connection. The small wire I ran through a 470ohm resistor then to my dashboard voltmeter.

From previous research I think the following terminology is correct. Every altenator/generator will have a main power wire. However, there are different technologies for converting AC to DC. A single small wire is considered single phase and two small wires is termed a dual phase. I found a web site for aftermarket high efficiency high performance altenators that explained all of this well. However, I am having difficulties finding the site again.

 

Maybe some helpful direction.
http://www.alternatorparts.com/what_...alternator.htm


Additional question. Does anyone know how to drive the fan relay. I am not sure if the relay is driven directly from the yellow or black wire of the temp sending unit. Or from the computer. There are two pins on the computer that are designated as pri/lo fan on and sec/high fan on. I am not getting any power from the pri/lo pin output...

Any insight is appreciated.

Gus

 

I think I finally figured out the alternator. I connected the battery and everything seems fine with the car not running. I also turned the key to crank for a split second and it turned over.

As for the fan stuff...I believe it comes out of the ECM as a negative polarity and goes from there to a relay which would turn on the fans once it sees this.

Someone correct me if I'm wrong here.