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post #1 of (permalink) Old 01-08-2001, 10:36 PM
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brand new 258 Alternator voltage drops at idle

I have been having electrical problems in my '83 258 CJ-7 recently. i thought i had bad alternators, but i am thinking the problem is elsewhere. 2 days ago, i put in a Duralast 94 amp lifetime warranty alternator, b/c my 140 amp Powermaster kicked the bucket. now this new one is starting to act the same way. at idle, with 3 electricals on,( ie: headlights, heat, driving lights) the voltage drops way down to 12, sometimes below, depending on how long i let it idle. then the alternator squeals loudly till it charges back up. At first i thought the Powermasters had bad voltage regulators, but this is the 4th alternator that is doing this. where else could the problem be? need i replace the whole wiring harness? that requires alot of cash that I dont have. i have a voltometer, are there any particular wires i should specifically look at?
Thanks alot,
1983 CJ7, 258 I6

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post #2 of (permalink) Old 01-09-2001, 02:41 AM
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Re: brand new 258 Alternator voltage drops at idle

A couple of straight forward things: Clean all alt. and bat. connections. Look for ground wires/cables/braided straps going from engine to frame, body to frame, battery to body, and battery to engine. Make sure these are clean and secure. I like to use a dielectric grease after cleaning to help ward off future corrosion. Belt squeals while alt. charging? Then it may be slipping while just trying to maintain battery. Tighten it. For "V" belts the old 1/2" of play is sometimes just not tight enough. How about a new belt that isn't dry rotted/checked? Idle too low? Sometimes an alternator just won't put out enough at low speeds. Take out your handy dandy pocket protected mini screw driver and have at it. Good Luck.

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post #3 of (permalink) Old 01-09-2001, 08:44 AM
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Re: brand new 258 Alternator voltage drops at idle

Stupid question, by i just want to make sure: What you mean by "have at it", you mean to boost up the idle, right? How do i check the amperage an electrical accessory is drawing?

Additional info I thought might be useful:
890 CA Exide Battery >1 yr old
New 4 guage battery and starter cables
New heater blower motor
All old 1983 wiring

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