I underestimated the alternator factor of my ls swap. I connected 12v to the 4 pin alternator exciter wire… sans resistor. It worked, but the charge was weak. And the alternator predictably failed prematurely. More research in ls1tech led me to the truck 145 amp alternator and Holley pigtail with resistor inline. This alternator fit and cleared the pitman arm. And my charge is finally over 14v. It’s a beautiful sight.

 

I am going to try this plug before redoing the wiring on my swap. It has always had a charging issue since I put it together 20 yrs ago..... lol

 

what engine / brackets are those?
im guessing camaro with the alt down low like that?

 

Is that a different car than this thread?: https://www.thirdgen.org/forums/ltx-...ml#post6135094

 

I have this plug, new, sealed and taking up space. Make me an offer if you'd like it.

 

That thread tells the story

E38 ECM, most of which use PWM alt control. Connecting that control wire to the old 4 pin exciter will quickly kill an alt

To use the resistor pigtail, hook it to 12v IGN, not computer control

When directly running the alt sans-computer, be sure to hit it with a temp gun and ensure the battery cable connections are very secure. Hot battery terminals will happen if the connection isn't tight

 

Yes, that's it. I used 4th gen alternator brackets which mounts the alternator low under the power steering pump. And I now know a direct 12v connection to alternator exciter input eventually caused it to fail.

 

Instead of making things complicated for no reason just buy this harness from sloppy mechanics. It steals power from the coil pack and plugs into the alternator. Totally plug n play and the alternator charges at 14.4v. I've been using this for a while now with zero issues

https://www.sloppymechanics.com/coll...rnator-exciter

 

I haven’t heard of sloppy mechanics, but I’ll check it out. I’m all for keeping it simple.

 

Hello Everyone, I have a 2 questions regarding the exciter pin/wire on my Stock 1987 IROC. Its the stock SFLP connector and the P pin is not used.
I am not an expert so I appoligize ahead of time if I use the wrong terminalogy.

I've seen lots of videos where people modifing older cars with the CS130 style alternators connect a small light buld to the L wire for required resistance or it kills the alternator.
#1 On a stock 1987 IROC is the battery light on the instrament panel the resistance, if so if that light bulb was burnt out is that the same as not having resistance and causing issues or is the required resistance happening somewhere else and a burnt bulb being irrelevent?
#2 How can I test for faulty or failure with the exciter signal and make sure that the charging system is sending the alternator the current to activate.

Thanks in advance.

Tony

 

Get your OG rebuilt, that’s what I do. Too many wrong things on them at the parts stores.

 

Definitely the way to go, if you can find high-quality repair parts.