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  #1  
Old 11-11-2012, 12:34 AM
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Wackyneer Wackyneer is offline
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Is My Alternator Going Bad?

Last night I noticed that (headlights on) when I was sitting at a traffic light,the voltage dropped from ~13 well in to the red zone. When I would start driving again, the voltage would climb back up to ~13. I also noticed a sharp drop when operating the power windows.
I'm guessing that the alternator isn't adding enough juice at idle. I should probably check the electrical connections for the alternator first and go from there. The battery is less than a year old with <1,000 miles on it.
Thoughts???
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Was it an omen that my '88 GW broke down 2 miles after the purchase and the tow truck broke down bringing it to my house?
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  #2  
Old 11-11-2012, 06:13 AM
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jeepfan93 jeepfan93 is offline
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Yea if you're not running a crazy stereo, lights or electric fans, sounds like it's time. I put a reman on my dad's 07 Denali, 2 months later put another in. Got it form Car Quest. I went to Advanced and got a new, not reman, for my F150 a few days later, same manufacturer.
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  #3  
Old 11-11-2012, 10:51 AM
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Carnuck Carnuck is offline
 
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KISS. (keep it simple suckah!) How old/worn is the belt? When they lose 1/4 of their width the belt drops to the bottom of the groove and the flat bottom can't grab well.
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  #4  
Old 11-11-2012, 12:15 PM
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Wackyneer Wackyneer is offline
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All beltswere replacedwhen I bought it. There are <1000 miles on the belts.
I should point out that I have had to tighten the dual belts twice due to squealing. For some reason, they keep losing tension. I'm afraid that if I torque the belts any tighter, I'll bust the bolt. I'm now thinking Loctite.
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'88 GW 360 V8, Almost stock (locking hubs and electric fuel pump)
Was it an omen that my '88 GW broke down 2 miles after the purchase and the tow truck broke down bringing it to my house?
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  #5  
Old 11-11-2012, 12:23 PM
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WHSII WHSII is offline
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the battery should also be tested, if it is going south, it will draw more current and when loading the system, it will show your symptoms.

Just my thoughts...
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Dad's J10, Honcho, 1980 Sport Side
Build http://www.ifsja.org/forums/vb/showthread.php?t=118144

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  #6  
Old 11-11-2012, 04:23 PM
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Rich88 Rich88 is offline
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Quote:
Originally Posted by Wackyneer
Last night I noticed that (headlights on) when I was sitting at a traffic light,the voltage dropped from ~13 well in to the red zone. When I would start driving again, the voltage would climb back up to ~13. I also noticed a sharp drop when operating the power windows.
I'm guessing that the alternator isn't adding enough juice at idle. I should probably check the electrical connections for the alternator first and go from there. The battery is less than a year old with <1,000 miles on it.
Thoughts???

Besides loose belt, next thing is a diode or two could have crapped out. One way to check is put a voltmeter across the battery and put it on AC. If a diode is bad it will detect the ripple as AC. More than .5V AC means Alt ain't no good no more.

Context for the electrically challenged: An alternator really makes AC (alternating current) like what's in your house. Hence the name "alternator". But built-in diodes are used to rectify it do DC. So if diodes go bad, you'll be getting DC with an AC "ripple" and all that much less DC current available to keep battery charged.
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88 GW 360-.030 over/2150/727/229/Posi, e-pump, AC (broke), tow package, Monroe Air Shocks, TFI, CTO-Free, AIR-free, oil & tranny coolers, dried knuckle blood all over, GM 350 TBI in a box, waiting...
"You're an FSJ'r when the parts guys memorize your name, phone & credit card#."
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  #7  
Old 11-12-2012, 06:28 AM
leadsled01 leadsled01 is offline
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If you do need to replace the alternator, don't buy a Power MAster.... When they stop working they will NOT warranty it and you will be stuck with a bad $200 alternator. I know this from experiance, times two!!!!
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  #8  
Old 11-13-2012, 12:54 PM
Joe Guilbeau Joe Guilbeau is offline
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Location: San Antonio, Texas
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Test Procedures

Scroll down to the flow chart troubleshooting diagram for a quick guide

http://www.pirate4x4.com/tech/billavista/Wiring/Part2/pdf's/diagnostic-manual.pdf
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Joe Guilbeau<br />1983 Cherokee Laredo WT (SJ-17), 360/229/727/D44/D60 4.10 Gearing, 8-lug hubs, Edelbrock Performer w/EGR Intake, Mallory Unilite Series 47 Photo-Optic Infrared Trigger Vacuum Distributor, Mallory Surge Protector, Mallory Promaster Coil, Holley Pro-Jection TBI 502-Analog, FlowKooler High Output Water Pump, Staggered 4-Core Custom Industrial Radiator, HD Fan Clutch, Dual Electric Fans, CS130 Delco 105-Amp Alternator, Oil Bypass Mods at Rear of Block and Distributor Oiling, Superlift 4\" Suspension, Rancho RS5000\'s, Hi-Tech 31\" Re-Treads, Aero 33 Gal Tank w/Skid Plate, Custom Rear \"Longhorn\" Bumper
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  #9  
Old 11-13-2012, 12:58 PM
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serehill serehill is offline
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Hmm

Linky brokey
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80 Cherokee
360 ci 727 with
Comp cams 270 h
NP208
Edlebrock performer intake
Holley 4180
Msd total multi spark.
4" rusty's springs
Member, FSJ Prissy Restoration Association

If you can't make it better why waste your time. No use repeating the orignal mistakes. I'm to old to push it that's why.
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  #10  
Old 11-13-2012, 01:00 PM
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RWrightPhotog RWrightPhotog is offline
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I bought an Autozone reman alternator, no problems for about 4 months... was only like 30 to 40.
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1982 Jeep Wagoneer Limited 360
1979 Jeep Cherokee 4-Door 258
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  #11  
Old 11-13-2012, 07:29 PM
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Rich88 Rich88 is offline
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Quote:
Originally Posted by Joe Guilbeau
Scroll down to the flow chart troubleshooting diagram for a quick guide

http://www.pirate4x4.com/tech/billavista/Wiring/Part2/pdf's/diagnostic-manual.pdf

You realize you're busting a lot of myths, opinions and "experience" now.

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Jeepasaurus (Wagonus Grandi quadropedus)
88 GW 360-.030 over/2150/727/229/Posi, e-pump, AC (broke), tow package, Monroe Air Shocks, TFI, CTO-Free, AIR-free, oil & tranny coolers, dried knuckle blood all over, GM 350 TBI in a box, waiting...
"You're an FSJ'r when the parts guys memorize your name, phone & credit card#."
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  #12  
Old 11-13-2012, 08:45 PM
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serehill serehill is offline
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hmmm

Quote:
Originally Posted by Rich88
You realize you're busting a lot of myths, opinions and "experience" now.



Not really
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80 Cherokee
360 ci 727 with
Comp cams 270 h
NP208
Edlebrock performer intake
Holley 4180
Msd total multi spark.
4" rusty's springs
Member, FSJ Prissy Restoration Association

If you can't make it better why waste your time. No use repeating the orignal mistakes. I'm to old to push it that's why.
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  #13  
Old 11-14-2012, 02:18 PM
Joe Guilbeau Joe Guilbeau is offline
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Join Date: Apr 17, 2002
Location: San Antonio, Texas
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Quote:
Originally Posted by Rich88
You realize you're busting a lot of myths, opinions and "experience" now.


Like Dragnet...Just the Facts
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Joe Guilbeau<br />1983 Cherokee Laredo WT (SJ-17), 360/229/727/D44/D60 4.10 Gearing, 8-lug hubs, Edelbrock Performer w/EGR Intake, Mallory Unilite Series 47 Photo-Optic Infrared Trigger Vacuum Distributor, Mallory Surge Protector, Mallory Promaster Coil, Holley Pro-Jection TBI 502-Analog, FlowKooler High Output Water Pump, Staggered 4-Core Custom Industrial Radiator, HD Fan Clutch, Dual Electric Fans, CS130 Delco 105-Amp Alternator, Oil Bypass Mods at Rear of Block and Distributor Oiling, Superlift 4\" Suspension, Rancho RS5000\'s, Hi-Tech 31\" Re-Treads, Aero 33 Gal Tank w/Skid Plate, Custom Rear \"Longhorn\" Bumper
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  #14  
Old 11-14-2012, 09:29 PM
Rich88's Avatar
Rich88 Rich88 is offline
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Quote:
Originally Posted by serehill
Not really

I hope you know I wasn't referring to you. If not, let it be written.

Otherwise Joe's posts ought to be stickies.
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Jeepasaurus (Wagonus Grandi quadropedus)
88 GW 360-.030 over/2150/727/229/Posi, e-pump, AC (broke), tow package, Monroe Air Shocks, TFI, CTO-Free, AIR-free, oil & tranny coolers, dried knuckle blood all over, GM 350 TBI in a box, waiting...
"You're an FSJ'r when the parts guys memorize your name, phone & credit card#."
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