View Single Post
  #10 (permalink)  
Old 07-06-2024, 09:48 AM
C5GTO's Avatar
C5GTO C5GTO is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2015
Location: Prescott, AZ
Cobra Make, Engine: Classic Roadsters
Posts: 207
Not Ranked     
Default

Quote:
Originally Posted by Shawn Erwin View Post
Greetings Everyone,

I need help with my alternator. I have no idea what make it is but it is set up for a "one wire" application. I was anticipating a radiator fan upgrade and needed more juice and I had the alternator rebuilt to about 150 amps. Now the issue, at idle, the alternator is only maintaining 12 volts or lower. At driving speed, the system begins to charge all the way up to 13.7 to 14 volts. As you guys know this is a problem when running a dual radiator fan set up at a stop light in the summer with the lights on.

Another interesting thing is that there is another smaller wire running off a an alternator plug to the wiring harness. The female end of the plug has four pins and the wire is coming of the second pin. I have no idea what this wire is for - energizer wire? Everything that I have researched on current aftermarket one wire alternators don't need a separate wire coming going to the harness.

I have attached photos of the alternator, plug, and the small wire coming off of the alternator in hopes that someone can identify it and the purpose of the small wire.

Thanks in advance.

Cheers,
Shawn
I'm not an alternator expert but your alternator looks just like the one in my Cobra. Mine is an GM one wire from an intermediate sized car, I beleive late 90's or early 2000s. 150 amps sounds just about right. My alternator guy built mine for me and clocked the housing so it would work in the Ford configuration. Mine has the slot with 4 pins but these are not used. I really do just have a single wire going the the battery on my setup.

In the 1 wire configuration, the alternator needs to be spun up (about 1,200 engine rpm) before it energized and starts producing power. On mine, once it's producing power, it keeps the system at 14.5 volts even at an engine idle. My car only has a single coolant fan but it does draw about 20 amps. I've also got EFI, so electric fuel pump and all the other electric stuff that goes with it.

If you had someone work on your alternator, I'd take it back and have the test/fix it. If yours is the same as alternator as mine, it's very capable of producing more than enough power for a Cobra.
__________________
Thanks,
Joel Heinke (early 90's CRL Cobra)
Reply With Quote