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Unread 04-21-2014, 05:21 PM   #1
CadCaman
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Alternator Wiring Issue

Guys, I am getting a sever squealing from my alternator at start-up that lasts about 5 seconds and then it is gone. The voltage meter on the dash reads about 12 for those 5 seconds then jumps to 14.5 immediately when the squealing stops.

You might just say "check your belt" or "alternator bearings". However when I unhook a single wire from the alternator (the wire that is fed from the starter solenoid to the post on the back of the alternator and then to the two-wire hook-up on the side of the alternator) the squealing stops. It is not coincidence because I made the condition repeat and cease 5 times by removing the wire from the alternator.

Can anyone help me with this dilemma?

Thanks for reading guys,

Jeff

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Unread 04-21-2014, 05:40 PM   #2
LumpyGrits
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Pull the belt and see how ALL the pulleys feel when you spin them buy hand.
Something is cause'n the belt to slip-somewhere.
How old is this belt and how deep does it ride in the 'V" of the pulley?
LG
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Unread 04-21-2014, 08:20 PM   #3
Mike Romain
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When you unplug the alternator, you take the load off it and the belt stops slipping. To test, I take a cold off engine and see if I can hand slip the alternator pulley. If I can, it will for sure slip under the load needed to top up the battery from the last starter draw. It takes several HP to spin the alternator under load.
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Unread 04-21-2014, 08:26 PM   #4
CadCaman
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That makes sense (no resistance). I am going to take the belt off and see if the alternator spins freely. I suspect it will. I know I have the belt tight enough. Could I be using the wrong style of belt? Is there such a thing as different belts? I am getting frustrated.

Thanks for the help.

Jeff
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Unread 04-21-2014, 09:20 PM   #5
firegod33
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There are differences in belts, quality, length, and width. You may want to try spending the extra couple bucks on the Goodyear Gatorback belt.
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Unread 04-21-2014, 09:56 PM   #6
RedNeckCorvette
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I had a water pump freeze in a 258 once, at start up the belt slipped and cut a groove in the pulley. Had to change the pulley.
Red Neck
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Unread 04-22-2014, 04:12 AM   #7
Mike Romain
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Quote:
Originally Posted by CadCaman View Post
That makes sense (no resistance). I am going to take the belt off and see if the alternator spins freely. I suspect it will. I know I have the belt tight enough. Could I be using the wrong style of belt? Is there such a thing as different belts? I am getting frustrated.

Thanks for the help.

Jeff
You really need to do the pulley slip test or you are just looking for trouble that doesn't exist.

When I do the pulley slip test and I know the belt is tight enough, and it still slips, it just means the belt has gotten polished up from mud usually in my case. I then need a new belt. Mud=liquid sandpaper.

If the pulley test fails, and the pulley does grab hard, next I check my battery cable ends for corrosion. Every time my cable ends need cleaning, the alternator will slip like that because of the real high load after a start. Alternator has to work double time to try and pass current across corroded cable ends. Don't forget the cables have 2 ends and both get corroded.
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86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
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Unread 04-22-2014, 04:46 AM   #8
86cj74.2L
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Tighten your belt. It requires HP to spin the ALT when its charging the battery and providing power for the accessories.
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Unread 04-22-2014, 08:24 AM   #9
ThisGuyUKnow
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Quote:
Originally Posted by Mike Romain View Post
When you unplug the alternator, you take the load off it and the belt stops slipping. To test, I take a cold off engine and see if I can hand slip the alternator pulley. If I can, it will for sure slip under the load needed to top up the battery from the last starter draw. It takes several HP to spin the alternator under load.
x2 when you unplug everything from the alternator it doesnt sense that the car is on or that volatage is required so the pulley will just turn freely with no resistance like a ac clutch pulley when it isnt activated.

The test you did actually indicates the opposite of your conclusion, it makes it seem like the belt is slipping under load.
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Unread 04-22-2014, 08:36 AM   #10
CadCaman
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I believe you are correct. I am going to get it all checked out tonight.

Thanks for your help.

Jeff
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Unread 04-22-2014, 08:43 AM   #11
BHawkmeck
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What has happened to me before sounds like what is going on with yours. Even though you change the belt it still might squeal. Check ALL the pulleys on the engine. After all these years they do get worn down to the point that only the edges of the belt are touching the pulleys.
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Unread 04-22-2014, 08:46 AM   #12
CadCaman
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I will check that.

Thanks
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Unread 04-22-2014, 09:46 AM   #13
86cj74.2L
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If you do not know how to tension the belt properly ask.

In this age of automatic belt tensioners................
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Unread 04-22-2014, 10:07 AM   #14
CadCaman
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OK how do you tension the belt correctly? I have been taking a prybar and jamming it between the alternator and the block and then prying it tight while tightening the 3/8" bolt on the adjuster bracket (curved and slotted piece).

I am guessing that isn't right.

Thanks,

Jeff
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Unread 04-22-2014, 10:29 AM   #15
texasdave
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New belt 125-155 foot lbs. Used belt 90-115 foot lbs using a belt tensioner tool J-23600. Or You can push on it mid way and you should have at least 1/2 inch of deflection.
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