Alternator demon

S

SpyderDiablo

Registered
Hi all. I have a 93 Mark VIII, 103k, bone stock except for the air ride conversion. I have replaced 5 (five) alternators in the past 2 yrs. most were bad regulators, but this morning, after replacing it two months ago, i replaced it again because of bad diodes. Any ideas on what is frying my alternator? Thanks in advance.
 
You could have a loose connection between the battery and the frame or the battery and the alternator.

The alternator/regulator uses the battery to limit the voltage the alternator will generate. If the battery becomes disconnected, the alternator will output maximum voltage -- usually over 50 volts. It just so happens that the diodes are rated at 50 volts, so they could go.

Typically, a car with a loose battery connection will also be real hard on light bulbs and electronics.

You might want to put an oscilloscope on the car's electrical system and look at the charge waveform. If there are spikes -- there is a loose connection somewhere.
 
What brand are you using?

Only use new Motorcraft/Autolite or Rebuld MOTORCRAFT only... all others will fail within months or even days. Also the battery needs to be full during alternator changes.
 
Also check the pigtail to the alt.
You can buy the pigtail from most local auto stores
Ditto on what maxmk8 said about which alt. to buy.
Some like PA-Performance I never used one but heard good reviews.
 
I know the connections are good, I just did a major tune-up (AutoLite Double platinum Plugs, 10mm wires, Wix air filter, etc.) I also did a compression test, checked all vacuum lines, and replaced ALL battery cables. I don't think it's a real big deal, since I have a lifetime replacement from O'Reillys on the Alt. It's just annoying to have to spend 30 mins taking it off, and replacing it. Last time I replaced it, it was a bad regulator. My cruise control, and A/C paneln would only work when I was stopped. Soon as I hit the gas, A/C went off, and I didn't have cruise control (no big loss). I've got a Chilton Book for 88-00 Lincoln cars, if anyone's interested in a pdf of it let me know.
 
I would be sure that your complete system gets analyzed (they should have a unit to roll out to the car). I have found a number of times that the battery condition at times will cause a problem with alternator life as mentioned above. It's a wonder that the store manager has insisted on doing so sooner. That's retail management for you.
 
$322 for a rebuilt unit is a complete rip off... You can buy a ford unit cheaper than that... and have it mailed to you. That said unfortunatly you're stuck with your current unit but I would try to get my money back and put it towards another alternator.
 
Alt. Demon

Alt. Demon

You can add to the list a new battery today, and glue to put my rear view mirror back on, which fell off early today. I'm just waiting on the starter to go out now, lol. Anyways, does anyone know of a good interior guy in Texas that can put my moon roof cover back on, the fabric is starting to come off of one of the corners.
 
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