Alternator voltage, Need help -
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Unread 07-10-2011, 08:21 AM   #1
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rhbflyfish's Avatar
1984 CJ7 
Join Date: Jan 2007
Location: Sanibel Island, Florida
Posts: 65
Alternator voltage, Need help

I have an 84 CJ7 with a AMC 360. The Jeep and Motor were rebuilt in 2007. It has a dual battery system and a MSD 6A ignition with MSD billet distributor.
The Jeep has been running fine until last weekend when it failed to start due to low batteries. After charging the batteries, I ran an alternator test and it failed. I took the alternator to the Zone where it was benched and failed. I purchased a rebuilt 78 amp alternator installed it and it still was not generating more than 12.5 volts and failed the alternator test on my tester . I returned the alternator where it was bench tested and passed. I than replaced the starter solenoid, removed and cleaned every terminal connector, battery terminal and ground wire. I returned that alternator and purchased a different brand and same result it will not pass the alternator test. I than ran a test directly from the alternator output stud and ground stud and still only have 12.5 volts, on the bench it read max 14.8 and averaged 13.5. I have double checked the belts and pulleys.
What am I missing? Is the ignition pulling that much voltage to cause this? I do not mind purchasing a heavy duty alternator; quadratec 100/70 amp, if that is the fix. PS. on another note in all the start/restart process the key broke off in the ignition switch, I would appreciate direction to the link with photos for the NON TILT WHEEL switch replacement instruction.

Thanks for the help

85 CJ7 w/AMC 304, Edelbrock RPM with Holley 4bbl, MSD off road /T150 ,Hedmans with cat back flow masters,4" body lift, 32 swampers, Body Armor rear bumper, nerf bars

84 CJ7 w/AMC 360, Bored over, Crane cam, RPM, Performer 4bbl, MSD 6A, MSD Pro Billet, Hooker straight thrus,T177, 2.5 Suspension,33" BFG's on MT', chrome running bars, Warn 9.5ti, Body armor front and rear bumpers
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