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High Pitch squeal. Related to alternator

 
Old 05-14-2019, 11:35 PM
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UmX
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Default High Pitch squeal. Related to alternator

I am copy pasting this from the z06 group on facebook. I cant link the video to here..

So I have a 06 z51. When I start the car the alternator is not charging the car and makes a loud as squeal noise. It did it on my old alternator and a new one I just bought. When I unplugged the harness going into the alternator the noise stopped and when I plugged it back in it started squealing again. I removed all devices that required power. Fans amps and so forth. If I let it run for a few mins it will start to charge again and then stop the start again. As long as the alternator is charging there is no noise only when it's not charging does it squeal. So I am looking for help. I also replaced the belt with a brand new one..
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Old 05-15-2019, 10:36 AM
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I had this same problem on an '07 base plus the power steering was weak. The harmonic balancer/crankshaft pulley had a severe wobble and the bolt had come loose. The belt and pulleys stopped turning at idle. Check it with the hood up and see if the belt and pulleys are moving.

Last edited by gtmalone; 05-15-2019 at 10:43 AM.
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Old 05-15-2019, 11:24 AM
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I actually have a secondary drive kit installed on the system and all pulleys spinning. It will squeal when I start the car bc the alternator is putting out no voltage I checked with a volt meter. After a few mins if it start charging and then stop squealing


Originally Posted by gtmalone View Post
I had this same problem on an '07 base plus the power steering was weak. The harmonic balancer/crankshaft pulley had a severe wobble and the bolt had come loose. The belt and pulleys stopped turning at idle. Check it with the hood up and see if the belt and pulleys are moving.
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Old 05-15-2019, 06:05 PM
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Originally Posted by UmX View Post
I actually have a secondary drive kit installed on the system and all pulleys spinning. It will squeal when I start the car bc the alternator is putting out no voltage I checked with a volt meter. After a few mins if it start charging and then stop squealing
That sounds like a short in the alt or the charging circuit. A short or near-short would cause an extraordinary load on the alt and make it difficult to turn. Do you have any overheated electrical smell?
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Old 05-15-2019, 06:54 PM
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Originally Posted by gtmalone View Post
That sounds like a short in the alt or the charging circuit. A short or near-short would cause an extraordinary load on the alt and make it difficult to turn. Do you have any overheated electrical smell?

the harness that was going to the alternator was kinda melted just from heat so i bought a new pigtail and wire a new one in and still did it..

i dont think it has anythign to do with the alt bc i dropped in a brand new alt and it still did it..

only thing i can think of is trace the 3 wires in the harness but idk where they go im guessing computers in the fender.

Last edited by UmX; 05-15-2019 at 06:55 PM.
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Old 05-16-2019, 04:06 PM
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I would trace the large cable on the back of the alt. It probably works it's way down to the starter to connect to the + batt cable (keep me honest here - I haven't looked under there to check). It may have rubbed on something or got hot and melted the insulation.

Keep us posted.
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Old 05-16-2019, 04:43 PM
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I have my alternator ran to battery then to starter. It's been this way for a long time with no issues. I ran a new 4ga wire from battery to alternator last fall worked perfect.
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Old 05-16-2019, 04:54 PM
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Originally Posted by UmX View Post
the harness that was going to the alternator was kinda melted just from heat so i bought a new pigtail and wire a new one in and still did it..

i dont think it has anythign to do with the alt bc i dropped in a brand new alt and it still did it..

only thing i can think of is trace the 3 wires in the harness but idk where they go im guessing computers in the fender.
I very much doubt that underhood temps are going to melt your wiring harness. Sure sounds like a short to ground in the harness. I would

1) Disconnect the battery
2) Use an ohm meter and check each wire in the harness's resistance to ground.

You might want to hunt around on the forum and get a wiring diagram so that you know where the wires terminate, and whether or not you should see an open circuit to ground.
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Old 05-16-2019, 04:57 PM
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Old 05-16-2019, 05:00 PM
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idk where C and b go to

idk what a generator turn on signal is im guessing ignition, and or field duty cycle signal
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Old 05-16-2019, 06:46 PM
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D - Rd/wh is reading 11.8 volts
C - was reading .10volts
B: was reading 5.0volts this was when the car was charging and i unplugged the harness and muti metered it..

I noticed when its squealing
C was .04v
B was .18v .

I have no idea what this stuff is supposed to be. normally
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Old 05-16-2019, 08:10 PM
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Have you looked at the starter solenoid to check for melting?
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Old 05-16-2019, 08:59 PM
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Originally Posted by ruxvette View Post
Have you looked at the starter solenoid to check for melting?
\

starter looks fine and cranks and fires up no issues..

checked grey wire from pcm to alternator and had zero resistance ohm wise, orange wire had 5v at pcm when car was started and running and rd/wh remained battery voltage

Last edited by UmX; 05-16-2019 at 09:01 PM.
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Old 05-17-2019, 05:47 PM
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1. Tried 3 alternators

2. New tensioner

3. New belt ( smaller)

4. New alt harness

5. New battery

6. Traced lines from pcm to alt

7. Unhooked radio, amp power, and grounds

8. Added 2nd ground to battery and alternator

9. Added 2nd power to alternator.

10. Burned car to ground ,


- touching alt cable to battery side

- watching grey wire in alt harness
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Old 05-17-2019, 06:02 PM
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Originally Posted by UmX View Post
...watching grey wire in alt harness
I have no idea what the problem is but my dog took off for the next county when the second video started...
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Old 05-17-2019, 06:15 PM
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Originally Posted by ruxvette View Post
I have no idea what the problem is but my dog took off for the next county when the second video started...

lol
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