Electrical 93 Cobra Charging Issue

emba129

Member
Jun 10, 2012
17
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Hi all, I was driving my 93 cobra last weekend in the 90 degree weather. went to a few places. On the way home, the battery light came on and the volt meter was barely above 8VDC. The battery is brand new, but got drawn down to the point of the car quitting luckily just when I got it home.

When the car is cold, the alternator is charging properly at about 13.8v. Seems to happen when the car is hot.. intermittently.

The alternator is a remanufactured Motorcraft. I assume a stock 75A unit. I dont know how old it is, but the car has only 64K miles on it. Seems newer. See pics

Im going to bring it to Autozone for a bench test. I am suspecting it will show good since I think the failure is high temp related. Im suspecting the voltage regulator is bad. Would you recommend replacing just the regulator or a new alternator. Looking for recommendations on good replacement parts/brands for both.
 

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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Massachusetts
I would try replacing the voltage regulator first but you won't find Motorcraft regulators available anymore.

If staying original isn't a concern, i would use the opportunity to move to a 3G or 6G alt.
 

emba129

Member
Jun 10, 2012
17
4
13
Just came back from Autozone. The alternator/regulator passed all tests. Im gonna try a new regulator first. Suspect failure at heat soak. Especially since it's intermittent.

Any tricks on possibly deflecting the heat behind the alternator to protect the regulator? shield ideas?
 

Dan02gt

mazing how much gas smell came from that tiny hole
10 Year Member
Mar 2, 2003
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Greenville, NC
Looks to me like it has been upgraded to a 130A 3G alternator at some point. Check the connections on the starter solenoid on your firewall. Also when they did the upgrade they didn't upgrade the alternator wiring so it's possible the fusible links are fried.
 

emba129

Member
Jun 10, 2012
17
4
13
you are correct. it is a 3G unit .. which is good. Ive cleaned the grounds and mounting interfaces. Im getting a voltage regulator for a 94+ . Checking all the wiring and will give it a go.