alternator question!!!!!!!!!!

[69camarokid]

ok... so im having some more problems with my 69 camaro LT1/t56 swap.

I know, i know... big shocker right hahaha

Im stoked to say the car turns on and runs fine now... yah!
But after a 20 or so minute break in drive i parked. when i came back out a 20minutes later the car wouldnt start. The battery was completly dead. A huge ass battery charger couldnt bring it to life.

This leads me to believe that my altornator is not charging my battery... do u guys agree?:candle:

ANd if that is the case, how can i tell if the alternator is bad or if im just a wiring retard (which i most definitely am!) and just didnt wire up the aternator right.

As of right now i have a wire running to the alternator from the starter, which is connected straight to the battery. Other than that i only have a small pigtail that plugs into the bottom of the alternator. So im thinking maybe i need to put another wire in there somewhere to charge the battery from the alternator....

what do u guys think? sorry this was such a long and boring read.
thanks for the advice!

[matty b]

few things, how long have you been using the battery to crank on the engine without it running? It possible you severly discharged it constantly cranking the motor and it not being charged. Second is the bat lead tight at the starter and at the alternator? Sounds stupid but Ive seen it more than a few times. Also make sure that the terminals are crimped on tight. You should be able to give it a good tug without it coming loose. I had a car in the shop with a similar problem except it was the main power feed at the battery and the wire was loose in the terminal and causing the car to die intermittently. Third how is the alternator plug wired up? The wires on the plug should be setup as follows. The terminal closest to the battery stud should have ignition power to it. The wire furthest from the stud should be wired over to the battery stud. The ignition wire turns on the regulator, the other wire senses the voltage coming out of the alternator. Get a test light and check these two things. After that if everything checks out then get yourself a new alternator.

[David Pozzi]

You should have 14 to 14.5volts at the battery when running. Anything less, the alt is not working.

[matty b]

well thats not entirely true, something as stupid as a loose belt would keep the alternator from spinning fast enough to output the voltage but the alternator itself is fine. If voltage is at least a volt over base voltage then its working. There are quite a few alternators that only run as much at the battery as necessary for given load requirements. All new cars that utilize computer controlled alternators do this LS motors included. Just FYI that your gauge may read only 13.1 volts or so at certain times and all is fine its just working the way its supposed to.

[69camarokid]

ok... so it turns out im just retarded.
On the bottom of the LT1 alternator there is a pigtail that plugs in. A black one with a red wire coming from it.

I turns out then when i was removing redundant and unecassary wires from the harness i acidentally removed this wire/pigtail. I need to reinstall it but i cannot find where the wire originally came from to reattatch it. Does anyone know where the alternator pigtail wire connects to???

[David Pozzi]

matty b,
Thanks for that info. I'm not up to speed on the newer stuff.

[matty b]

ok... so it turns out im just retarded.
On the bottom of the LT1 alternator there is a pigtail that plugs in. A black one with a red wire coming from it.

I turns out then when i was removing redundant and unecassary wires from the harness i acidentally removed this wire/pigtail. I need to reinstall it but i cannot find where the wire originally came from to reattatch it. Does anyone know where the alternator pigtail wire connects to???
I told you where the wires go dude.hook em up like I said and youll be in buisness

[69camarokid]

I told you where the wires go dude.hook em up like I said and youll be in buisness

I was a little confused by what you wrote earlier because you described how to hook up two wires coming from the pigtail, but its a single wire system...

[69camarokid]

f Third how is the alternator plug wired up? The wires on the plug should be setup as follows. The terminal closest to the battery stud should have ignition power to it. The wire furthest from the stud should be wired over to the battery stud. The ignition wire turns on the regulator, the other wire senses the voltage coming out of the alternator. Get a test light and check these two things. After that if everything checks out then get yourself a new alternator.

Im sorry man, but im really confused by this.
What do u mean by the terminal closest to thebattery stud.

Im not very good with wiring so theres a good chance its just ignorance thats keeping me from being able to understand ur instructions. But just incase its not i just need to know where to attatch the one single red wire that comes from the alternator pigtail. I cant find on any wiring diagram where that wire goes to

[69camarokid]

Just wanted to say thanks for all the help. I soldered in a 470 ohm resistor between my volt gauge and the alternator nad now im pulling a solid 13.7 volts at the battery while at idle...

so.. thanks guys...
u guys are alright, i dont care what they say about u behind ur backs... haha

[paul67]

What is it showing when you have lights on or the fans running, as you might a few more grounds.

[69camarokid]

you make a good point there.

It pulls 13.7 with the fans running, but i dont know how much with the lights on... ill check that tonight.

How would i wire up some grounds to the alternator??? or did you mean to the battery?

[paul67]

frame to battery ,engine to battery ,frame to engine, at 13.7 with the fans running if it stays the same with the lights on as well it should be ok at that.

[69camarokid]

checked it again last night.... 14.2 at idle.... 14.1 with the lights on

[paul67]

Thats great :woot:

[Steve N 69 69 69]

YAY!!! ( actual glee, not to be confused with retard voice on Crank Yankers)
good to hear its working.
you can hook up a light, in place of the resistor, to have a cute little light come on if the alt. takes a crap. ( looks pro! )

I put mine next to the Volt gauge on my blazer dash ( i put a CS144 alt. in it, same as the lt1's have) it works great.
https://static1.pt-content.com/images/pt/2008/05/medium-1.jpg

[willih6996]

Just for future reference, here is how you can also test an alternator if you think you are having a charging issue.

This is out of a FLUKE Multi-Meter Owners Manual.

Testing Ripple Voltage on an Alternator
Ripple voltage or ac voltage can be measured by
switching your meter to ac and connecting the black lead
to a good ground and the red lead to the “BAT” terminal
on the back of the alternator (not at the battery).
1. Insert the test leads as shown in Figure 13.
2. Set the rotary switch to K.
3. Touch the red probe to the “BAT” side of the
alternator and the black probe to ground.
4. Read the display. A good alternator should measure
less than 0.5 V ac with the engine running. A higher
reading indicates damaged alternator diodes.

Check out the PDF below
PAGE 45 is Figure 13. stated above in line one.

23662

[69camarokid]

sweet. thanks for the ideas... much appriciated!