Hey I have a 1992 camaro I swapped a 5.3 in it and I can't get the alternator to charge. Tried 2 different alternators, tried the resistors, and made sure grounds were good. Engine is a 2001 5.3 with a harness made for a 2002 camaro and pcm is for 2002 camaro. Alternator is for 2002 camaro. I have pin B wired with key on power and 470 ohm resistor. Alternator is charging at 13.6 volts and if I turn headlights on battery will die after about 30 min of driving.

 

Alt exciter wire is hooked to the wrong wire if it stops charging with the headlights on

 

Hey thanks for the reply but I hooked up the exciter wire to pin B or the L terminal on the alternator and that should be the right one based on all the diagrams I've looked at. I was thinking about running the 12 volt supply straight to the battery to the post on the back of alt. Instead of the connection point by battery.

 

Im using a truck alt thats 140amp stock from newer 2002+escaldes etc.It uses the same plug and bolt pattern for an ls1 fbody,it has one wire the goes to pcm,no resistor inline.Havent had any charging issues and I run a fair sized stereo and other accessories and havent dipped below 13.5 volts.many have posted about using this larger stock alt on ls1tech and never looking back..and I have to agree.

Are you running a internet bought high amp alt.?They are known to fail out of the box.

 

My wire to the battery is also 2 gauge wire from the starter to the alt. then the battery.Same with my engine grounds to each head and one to the block and battery ground.Dimming head lights and low voltage at idle are a thing of the past.

 

Yeah I am running a high amp alt that I bought off the internet. I will connect the 2 gauge alternator wire directly to the battery and see if that helps. Right now it is going through 2 junction connections and back to the battery on the little 10 gauge wire from the factory.

 

Get rid of that high output fake alt.Use a stock truck alt thats 140amp and same bolt pattern as the fbody.ts slightly oversized and tight fit on my car.I had to notch the sub brace between the frame and the kmember so that the main power wire would not short against it.You will also have to really pull on the belt tensioner to get the belt back on lol but it works perfect.Ill take pics tonight when I get my exhaust done.But many people have reported about having charging issues on here and especially on Tech about going with the gm truck alt. and using the same plug.There is no resistor on that single wire going to the ecm on my swap,I was told I dont need that on a ls1 but you do on the lt1 swaps I believe.

 

I had a charging issue on my car when I first built it. If you are using the original plug for the alt, with the original wire, check the continuity of that wire from the plug back a few inches.

Those little wires are very fragile, and almost always get broken especially when really moving them around during a swap or when removing the harness.

I ended up buying a repair harness from GM. It came with the new plug, and 5 new wires with the snap in terminals already crimped on. I took out the extra wires, and tucked them away. If the new wire ever breaks, I can just swap another one. Splice it back as far as you can go and youre good.

Of course this might not be your problem...but it gave me fits trying to diagnose my charging issue. Because it was intermittent. Apparently when Ide be testing it, it would be making connection. Then when Ide drive it would lose connection.

No resistors or anything on my LS1....goes straight to the PCM. In fact I did a continuity test between the PCM plug and the plug on the alt. Straight shot.

J.

 

I dont know what the other wires are for but Pocket told me that I only needed the red wire to be hooked up to the ecm and thats it.Havent had any issues to date.

 

Does anybody know for sure if the resistor is needed when using a 2002 harness and pcm. The harness I ordered came with one in it and it is a custom made harness off the internet.

 

99+ PCMs control the alt directly, no resistor needed

 

Straight to the PCM here also, no charging problems.